Marcelo G. Grecco EL GRAN DESPERTAR - DIVULGACIÓN y RESISTENCIA.

The WHO sees the integration of individual companies and communities that produce their own fabric masks as a potential social and economic benefit. Due to the global shortage of surgical masks and personal protective equipment, it sees this as a source of income and points out that the reuse of fabric masks can reduce costs and waste and contribute to sustainability [2]. In addition to the question of certification procedures for such fabric masks, it should also be mentioned that due to the extensive mask obligation, textile (artificial) substances in the form of micro- and nanoparticles, some of which cannot be degraded in the body, are chronically absorbed into the body through inhalation to an unusual extent. In the case of medical masks, disposable polymers such as polypropylene, polyurethane, polyacrylonitrile, polystyrene, polycarbonate, polyethylene and polyester should be mentioned [140]. ENT physicians have already been able to detect such particles in the nasal mucosa of mask wearers with mucosal reactions in the sense of a foreign body reaction with rhinitis [96]. In the case of community masks, other substances from the textile industry are likely to be added to those mentioned above. The body will try to absorb these substances through macrophages and scavenger cells in the respiratory tract and alveoli as part of a foreign body reaction, whereby toxin release and corresponding local and generalized reactions may occur in an unsuccessful attempt to break them down [172]. Extensive respiratory protection in permanent long-term use (24/7), at least from a theoretical point of view, also potentially carries the risk of leading to a mask-related pulmonary [47] or even generalized disorder, as is already known from textile workers chronically exposed to organic dusts in the Third World (byssinosis) [172]. For the general public, from a scientific angle, it is necessary to draw on the long-standing knowledge of respiratory protection in occupational medicine in order to protect children in particular from harm caused by uncertified masks and improper use. The universal undefined and extended mask requirement—without taking into account multiple predispositions and susceptibilities—contradicts the claim of an increasingly important individualized medicine with a focus on the unique characteristics of each individual [173]. A systematic review on the topic of masks is necessary according to the results of our scoping review. The primary studies often showed weaknesses in operationalization, especially in the evaluation of cognitive and neuropsychological parameters. Computerized test procedures will be useful here in the future. Mask research should also set itself the future goal of investigating and defining subgroups for whom respiratory protection use is particularly risky. 5. Limitations Our approach with a focus on negative effects is in line with Villalonga-Olives and Kawachi [12]. With the help of such selective questioning in the sense of dialectics, new insights can be gained that might otherwise have remained hidden. Our literature search focused on adverse negative effects of masks, in particular to point out risks especially for certain patient groups. Therefore, publications presenting only positive effects of masks were not considered in this review. For a compilation of studies with harmless results when using masks, reference must, therefore, be made to reviews with a different research objective, whereby attention must be paid to possible conflicts of interest there. Some of the studies excluded by us lacking negative effects have shown methodological weaknesses (small, non-uniform experimental groups, missing control group even without masks due to corona constraints, etc.) [174]. In other words, if no negative concomitant effects were described in publications, it does not necessarily mean that masks have exclusively positive effects.

De acuerdo con la literatura citada en la Sección 3.5 sobre efectos secundarios psiquiátricos (trastornos de la personalidad con ansiedad y ataques de pánico, claustrofobia, demencia y esquizofrenia), el enmascaramiento solo debe realizarse, si es que se hace, con una cuidadosa consideración de las ventajas y desventajas. Se debe prestar atención a la posible provocación del número y la gravedad de los ataques de pánico [ 77 , 78 , 79 ]. En pacientes con dolores de cabeza, se puede esperar un empeoramiento de los síntomas con el uso prolongado de la mascarilla (ver también la Sección 3.3 ., Efectos secundarios neurológicos) [ 27 , 66 , 67 , 68 ]. Como resultado del aumento de dióxido de carbono (CO 2 ) en sangre cuando se usa la máscara, se produce vasodilatación en el sistema nervioso central y disminuye la pulsación de los vasos sanguíneos [ 27 ]. A este respecto, también es interesante observar experimentos radiológicos que demuestran un aumento del volumen cerebral por debajo del umbral, pero aún dentro de los límites normales de CO 2.aumento de la sangre mediante resonancia magnética estructural. El aumento de dióxido de carbono en sangre se produjo en siete sujetos a través de la reinspiración con una concentración media de dióxido de carbono resultante de 42 mmHg y un rango intercuartílico de 39,44 mmHg, que corresponde solo a un aumento subumbral dados los valores normales de 32-45 mmHg. En el experimento, hubo un aumento significativo en el cerebro medible volumen del parénquima bajo aumento arterial CO 2 niveles ( p <0,02), con una disminución concomitante en espacios CSF ( p <0,04), totalmente de acuerdo con la doctrina Monroe-Kelly, de acuerdo a lo que el volumen total dentro del cráneo siempre permanece igual. Los autores interpretaron el aumento del volumen cerebral como una expresión de un aumento del volumen sanguíneo debido a un CO2 dilatación de los vasos cerebrales inducida por aumento [ 169 ]. Las consecuencias de tales aumentos igualmente por debajo del umbral de dióxido de carbono (CO 2 ) incluso bajo máscaras [ 13 , 15 , 18 , 19 , 22 , 23 , 25 ] no están claras para las personas con cambios patológicos dentro del cráneo (aneurismas, tumores, etc.) con cambios vasculares asociados [ 27 ] y cambios de volumen cerebral [ 169 ] especialmente debido a una exposición más prolongada mientras se usa una máscara, pero podrían ser de gran relevancia debido a los cambios de volumen relacionados con los gases en sangre que tienen lugar. En vista del aumento del volumen del espacio muerto, la acumulación y reinspiración aumentada y a largo plazo de otros componentes del aire respiratorio además del CO 2 tampoco tiene explicación, tanto en niños como en ancianos y enfermos. El aire exhalado contiene más de 250 sustancias, incluidos gases irritantes o tóxicos como óxidos de nitrógeno (NO), sulfuro de hidrógeno (H2S), isopreno y acetona [ 170 ]. En el caso de los óxidos de nitrógeno [ 47 ] y el sulfuro de hidrógeno [ 46 ], los efectos patológicos relacionados con la enfermedad se han descrito en la medicina ambiental incluso con una exposición baja pero crónica [ 46 , 47 , 48]. Entre los compuestos orgánicos volátiles en el aire exhalado, la acetona y el isopreno dominan en términos de cantidad, pero también deben mencionarse alil metil sulfuro, ácido propiónico y etanol (algunos de origen bacteriano) [ 171 ]. Aún no se ha aclarado si estas sustancias también reaccionan químicamente entre sí debajo de las máscaras y en el volumen del espacio muerto creado por las máscaras ( Figura 3 ), y con el tejido de la máscara, y en qué cantidades estos y los posibles productos de reacción se vuelven a respirar. Además de los cambios de gases en sangre descritos anteriormente ( caída de O 2 y CO 2aumento), estos efectos también podrían influir en los efectos indeseables de las mascarillas. Se necesita más investigación aquí y es de particular interés en el caso del uso prolongado y ubicuo de máscaras.

affects the fit of the mask (e.g., increased facial hair, craniofacial deformities, etc.). It is also important to emphasize the possible effects of masks in neurological diseases, as described earlier (Section 3.3). Both masks and face shields caused fear in 46% of children (37 out of 80) in a scientific study. If children are given the choice of whether the doctor examining them should wear a mask they reject this in 49% of the cases. Along with their parents, the children prefer the practitioner to wear a face visor (statistically significant with p < 0.0001) [134]. A recent observational study of tens of thousands of mask-wearing children in Germany helped the investigators objectify complaints of headaches (53%), difficulty concentrating (50%), joylessness (49%), learning difficulties (38%) and fatigue in 37% of the 25,930 children evaluated. Of the children observed, 25% had new onset anxiety and even nightmares [135]. In children, the threat scenarios generated by the environment are further maintained via masks, in some cases, even further intensified, and in this way, existing stress is intensified (presence of subconscious fears) [16,35,136,137]. This can in turn lead to an increase in psychosomatic and stress-related illnesses [74,75]. For example, according to an evaluation, 60% of mask wearers showed stress levels of the highest grade 10 on a scale of 1 to a maximum of 10. Less than 10% of the mask wearers surveyed had a stress level lower than 8 out of a possible 10 [74]. As children are considered a special group, the WHO also issued a separate guideline on the use of masks in children in the community in August 2020, explicitly advising policy makers and national authorities, given the limited evidence, that the benefits of mask use in children must be weighed up against the potential harms associated with mask use. This includes feasibility and discomfort, as well as social and communication concerns [100]. According to experts, masks block the foundation of human communication and the exchange of emotions and not only hinder learning but deprive children of the positive effects of smiling, laughing and emotional mimicry [42]. The effectiveness of masks in children as a viral protection is controversial, and there is a lack of evidence for their widespread use in children; this is also addressed in more detail by the scientists of the German University of Bremen in their thesis paper 2.0 and 3.0 [138]. 3.15. Effects on the Environment According to WHO estimates of a demand of 89 million masks per month, their global production will continue to increase under the Corona pandemic [139]. Due to the composition of, e.g., disposable surgical masks with polymers such as polypropylene, polyurethane, polyacrylonitrile, polystyrene, polycarbonate, polyethylene and polyester [140], an increasing global challenge, also from an environmental point of view, can be expected, especially outside Europe, in the absence of recycling and disposal strategies [139]. The aforementioned single use polymers have been identified as a significant source of plastic and plastic particles for the pollution of all water cycles up to the marine environment [141]. A significant health hazard factor is contributed by mask waste in the form of microplastics after decomposition into the food chain. Likewise, contaminated macroscopic disposable mask waste—especially before microscopic decay—represents a widespread medium for microbes (protozoa, bacteria, viruses, fungi) in terms of invasive pathogens [86,87,88,89,142]. Proper disposal of bio-contaminated everyday mask material is insufficiently regulated even in western countries. 4. Discussion The potential drastic and undesirable effects found in multidisciplinary areas illustrate the general scope of global decisions on masks in general public in the light of combating the pandemic. According to the literature found, there are clear, scientifically recorded adverse effects for the mask wearer, both on a psychological and on a social and physical level.

- Feeling of exhaustion [15,19,21,29,31,32,33,34,35,69] (Figure 2: Column 14). - Increase in respiratory rate [15,21,23,34] (Figure 2: Column 9). - Difficulty breathing and shortness of breath [15,19,21,23,25,29,31,34,35,71,85,101,133] (Figure 2: Column 13). - Headache [19,27,37,66,67,68,83] (Figure 2: Column 17). - Dizziness [23,29] (Figure 2: Column 16). - Feeling of dampness and heat [15,16,22,29,31,35,85,133] (Figure 2: Column 7). - Drowsiness (qualitative neurological deficits) [19,29,32,36,37] (Figure 2: Column 15). - Decrease in empathy perception [99] (Figure 2: Column 19). - Impaired skin barrier function with acne, itching and skin lesions [37,72,73] (Figure 2: Column 20–22). It can be deduced from the results that the effects described in healthy people are all more pronounced in sick people, since their compensatory mechanisms, depending on the severity of the illness, are reduced or even exhausted. Some existing studies on and with patients with measurable pathological effects of the masks support this assumption [19,23,25,34]. In most scientific studies, the exposure time to masks in the context of the measurements/investigations was significantly less (in relation to the total wearing and duration of use) than is expected of the general public under the current pandemic regulations and ordinances. The exposure time limits are little observed or knowingly disregarded in many areas today as already mentioned in Section 3.11 on occupational medicine. The above facts allow the conclusion that the described negative effects of masks, especially in some of our patients and the very elderly, may well be more severe and adverse with prolonged use than presented in some mask studies. From a doctor’s viewpoint, it may also be difficult to advise children and adults who, due to social pressure (to wear a mask) and the desire to feel they belong, suppress their own needs and concerns until the effects of masks have a noticeable negative impact on their health [76]. Nevertheless, the use of masks should be stopped immediately at the latest when shortness of breath, dizziness or vertigo occur [23,25]. From this aspect, it seems sensible for decision makers and authorities to provide information, to define instruction obligations and offer appropriate training for employers, teachers and other persons who have a supervisory or caregiving duty. Knowledge about first aid measures could also be refreshed and expanded accordingly in this regard. Elderly, high-risk patients with lung disease, cardiac patients, pregnant women or stroke patients are advised to consult a physician to discuss the safety of an N95 mask as their lung volume or cardiopulmonary performance may be reduced [23]. A correlation between age and the occurrence of the aforementioned symptoms while wearing a mask has been statistically proven [19]. Patients with reduced cardiopulmonary function are at increased risk of developing serious respiratory failure with mask use according to the referenced literature [34]. Without the possibility of continuous medical monitoring, it can be concluded that they should not wear masks without close monitoring. The American Asthma and Allergy Society has already advised caution in the use of masks with regard to the COVID-19 pandemic for people with moderate and severe lung disease [165]. Since the severely overweight, sleep apnea patients and overlap-COPD sufferers are known to be prone to hypercapnia, they also represent a risk group for serious adverse health effects under extensive mask use [163]. This is because the potential of masks to produce additional CO2 retention may not only have a disruptive effect on the blood gases and respiratory physiology of sufferers, but may also lead to further serious adverse health effects in the long term. Interestingly, in an animal experiment an increase in CO2 with hypercapnia leads to contraction of smooth airway muscles with constriction of bronchi [166].

HIF is a transcription factor that regulates cellular oxygen supply and activates signaling pathways relevant to adaptive responses. e.g., HIF inhibits stem cells, promotes tumor cell growth and inflammatory processes [160]. Based on the hypoxia- and hypercapnia-promoting effects of masks, which have been comprehensively described for the first time in our study, potential disruptive influences down to the intracellular level (HIF-a) can be assumed, especially through the prolonged and excessive use of masks. Thus, in addition to the vegetative chronic stress reaction in mask wearers, which is channeled via brain centers, there is also likely to be an adverse influence on metabolism at the cellular level. With the prospect of continued mask use in everyday life, this also opens up an interesting field of research for the future. The fact that prolonged exposure to latently elevated CO2 levels and unfavorable breathing air compositions has disease-promoting effects was recognized early on. As early as 1983, the WHO described “Sick Building Syndrome” (SBS) as a condition in which people living indoors experienced acute disease-relevant effects that increased with time of their stay, without specific causes or diseases [161,162]. The syndrome affects people who spend most of their time indoors, often with subliminally elevated CO2 levels, and are prone to symptoms such as increased heart rate, rise in blood pressure, headaches, fatigue and difficulty concentrating [38,162]. Some of the complaints described in the mask studies we found (Figure 2) are surprisingly similar to those of Sick Building Syndrome [161]. Temperature, carbon dioxide content of the air, headaches, dizziness, drowsiness and itching also play a role in Sick Building Syndrome. On the one hand, masks could themselves be responsible for effects such as those described for Sick Building Syndrome when used for a longer period of time. On the other hand, they could additionally intensify these effects when worn in air-conditioned buildings, especially when masks are mandatory indoors. Nevertheless, there was a tendency towards higher systolic blood pressure values in mask wearers in some studies [21,31,34], but statistical significance was only found in two studies [25,35]. However, we found more relevant and significant evidence of heart rate increase, headache, fatigue and concentration problems associated with mask wearers (Figure 2) indicating the clinical relevance of wearing masks. According to the scientific results and findings, masks have measurably harmful effects not only on healthy people, but also on sick people and their relevance is likely to increase with the duration of use [69]. Further research is needed here to shed light on the long-term consequences of widespread mask use with subthreshold hypoxia and hypercapnia in the general population, also regarding possible exacerbating effects on cardiorespiratory lifestyle diseases such as hypertension, sleep apnea and metabolic syndrome. The already often elevated blood carbon dioxide (CO2) levels in overweight people, sleep apnea patients and patients with overlap-COPD could possibly increase even further with everyday masks. Not only a high body mass index (BMI) but also sleep apnea are associated with hypercapnia during the day in these patients (even without masks) [19,163]. For such patients, hypercapnia means an increase in the risk of serious diseases with increased morbidity, which could then be further increased by excessive mask use [18,38]. The hypercapnia-induced effects of sympathetic stress activation are even cycle phase-dependent in women. Controlled by a progesterone mechanism, the sympathetic reaction, measured by increased blood pressure in the luteal phase, is considerably stronger [164]. This may also result in different sensitivities for healthy and sick women to undesirable effects masks have, which are related to an increase in carbon dioxide (CO2).

This effect could explain the observed pulmonary decompensations of patients with lung disease under masks (Section 3.2) [23,34]. Patients with renal insufficiency requiring dialysis are, according to the literature available, further candidates for a possible exemption from the mask requirement [34]. According to the criteria of the Centers for Disease Control and Prevention, GA, USA (CDC), sick and helpless people who cannot remove a mask on their own should be exempted from the mask requirement [82]. Since it can be assumed that children react even more sensitively to masks, the literature suggests that masks are a contraindication for children with epilepsies (hyperventilation as a trigger for seizures) [63]. In the field of pediatrics, special attention should also be paid to the mask symptoms described under psychological, psychiatric and sociological effects with possible triggering of panic attacks by CO2 rebreathing in the case of predisposition and also reinforcement of claustrophobic fears [77,78,79,167]. The mask-related disturbance of verbal [43,45,71] and non-verbal communication and, thus, of social interaction is particularly serious for children. Masks restrict social interaction and block positive perceptions (smiling and laughing) and emotional mimicry [42]. The proven mask-induced mild to moderate cognitive impairment with impaired thinking, decreased attention and dizziness [19,23,29,32,36,37,39,40,41,69], as well as the psychological and neurological effects [135], should be additionally taken into account when masks are compulsory at school and in the vicinity of both public and non-public transport, also regarding the possibility of an increased risk of accidents (see also occupational health side effects and hazards) [19,29,32,36,37]. The exclusion criteria mentioned in pediatric studies on masks (see pediatric impairments, Section 3.14) [26,133] should also apply to an exclusion of these children from the general mask obligation in accordance with the scientific findings for the protection of the sick children concerned. The long-term sociological, psychological and educational consequences of a comprehensive masking requirement extended to schools are also unpredictable with regard to the psychological and physical development of healthy children [42,135]. Interestingly, according to the Corona Thesis Paper of the University of Bremen children “are infected less often, they become ill less often, the lethality is close to zero, and they also pass on the infection less often”, according to the Thesis Paper 2.0 of the German University of Bremen on page 6 [138]. Studies conducted under real-life conditions with outcome endpoints showing hardly any infections, hardly any morbidity, hardly any mortality and only low contagiousness in children are clearly in the majority, according to Thesis Paper 3.0 of the German University of Bremen [138]. A recent German observational study (5600 reporting pediatricians) also showed a surprisingly low incidence of COVID-19 disease in children [168]. The infection of adults with SARS-CoV-2 by children has been considered in only one suspected case, but could not be proven with certainty, since the parents also had numerous contacts and exposure factors for viral infections due to their occupation. In this case, the circulating headlines in the public media that children contribute more to the incidence of infection are to be regarded as anecdotal. In pregnant women, the use of masks during exertion or at rest over long periods of time is to be regarded as critical as little research has been done on this [20]. If there is clear scientific evidence of increased dead space ventilation with possible accumulation of CO2 in the mother’s blood, the use of masks by pregnant women for more than 1 h, as well as under physical stress, should be avoided in order to protect the unborn child [20,22]. The hypercapnia-promoting masks could act as a confounder of the fetal/maternal CO2 gradient in this case (Section 3.6) [20,22,28].

It should not go unmentioned that very recent data suggest that the detection of SARS-CoV-2 infection does not seem to be directly related to popular mask use. The groups examined in a retrospective comparative study (infected with SARS-CoV-2 and not infected) did not differ in their habit of using masks: approximately 70% of the subjects in both groups always wore masks and another 14.4% of them frequently [143]. In a Danish prospective study on mask-wearing carried out on about 6000 participants and published in 2020, scientists found no statistically significant difference in the rates of SARS-CoV-2 infection when comparing the group of 3030 mask wearers with the 2994 mask-less participants in the study (p = 0.38) [132]. Indeed, in the case of viral infections, masks appear to be not only less effective than expected, but also not free of undesirable biological, chemical, physical and psychological side effects [67]. Accordingly, some experts claim that well-intentioned unprofessionalism can be quite dangerous [6]. The dermatological colleagues were the first to describe common adverse effects of mask-wearing in larger collectives. Simple, direct physical, chemical and biological effects of the masks with increases in temperature, humidity and mechanical irritation caused acne in up to 60% of wearers [37,71,72,73,85]. Other significantly documented consequences were eczema, skin damage and overall impaired skin barrier function [37,72,73]. These direct effects of mask use are an important pointer to further detrimental effects affecting other organ systems. En nuestro trabajo, hemos identificado numerosos efectos adversos científicamente validados y estadísticamente significativos de las mascarillas en varios campos de la medicina, especialmente con respecto a una influencia disruptiva en el proceso altamente complejo de la respiración y efectos negativos en la fisiología respiratoria y el metabolismo de los gases del cuerpo. (ver Figura 2 y Figura 3 ). La fisiología respiratoria y el intercambio de gases juegan un papel clave en el mantenimiento de un equilibrio saludable en el cuerpo humano [ 136 , 153 ]. Según los estudios que encontramos, un volumen de espacio muerto que casi se duplica con el uso de una máscara y una resistencia respiratoria más del doble ( Figura 3 ) [ 59 , 60 , 61] conducen a una nueva inhalación de dióxido de carbono con cada ciclo respiratorio [ 16 , 17 , 18 , 39 , 83 ] con, principalmente en personas sanas, un subumbral pero, en personas enfermas, un aumento parcialmente patológico en la presión parcial de dióxido de carbono (PaCO 2 ) en la sangre [ 25 , 34 , 58 ]. Según los estudios primarios encontrados, estos cambios contribuyen de forma refleja a un aumento de la frecuencia y profundidad respiratorias [ 21 , 23 , 34 , 36 ] con un aumento correspondiente en el trabajo de los músculos respiratorios a través de mecanismos de retroalimentación fisiológica [31 , 36 ]. Por lo tanto, no es, como se asumió inicialmente, un entrenamiento puramente positivo mediante el uso de máscaras. Esto a menudo aumenta la caída subliminal de la saturación de oxígeno SpO 2 en la sangre [ 23 , 28 , 29 , 30 , 32 ], que ya se reduce por el aumento del volumen del espacio muerto y el aumento de la resistencia respiratoria [ 18 , 31 ]. El posible descenso medible global resultante en la saturación de oxígeno O 2 de la sangre por un lado [ 18 , 23 , 28 , 29 , 30 , 32 ] y el aumento de dióxido de carbono (CO 2 ) por el otro [ 13 , 15 , 19 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ] contribuyen a una mayor respuesta al estrés noradrenérgico, con un aumento de la frecuencia cardíaca [ 29 , 30 ,35 ] y aumento de la frecuencia respiratoria [ 15 , 21 , 23 , 34 ], en algunos casos también a un aumento significativo de la presión arterial [ 25 , 35 ].

In our review, negative physical and psychological changes caused by masks could be objectified even in younger and healthy individuals. The physical and chemical parameters did not exceed the normal values in most cases but were statistically significantly measurable (p < 0.05) tending towards pathological ranges. They were accompanied by physical impairments (see Figure 2). It is well known that subthreshold stimuli are capable of causing pathological changes when exposed to them for a long time: not only a single high dose of a disturbance, but also a chronically persistent, subthreshold exposure to it often leads to illness [38,46,47,48,50,51,52,53,54]. The scientifically repeatedly measurable physical and chemical mask effects were often accompanied by typical subjective complaints and pathophysiological phenomena. The fact that these frequently occur simultaneously and together indicates a syndrome under masks. Figure 2 sums up the significant mask-dependent physiological, psychological, somatic and general pathological changes and their frequent occurrence together is striking. Within the framework of the quantitative evaluation of the experimental studies, we were actually able to prove a statistically significant correlation of the observed side effects of fatigue and oxygen depletion under mask use with p < 0.05. In addition, we found a frequent, simultaneous and joint occurrence of further undesirable effects in the scientific studies (Figure 2). Statistically significant associations of such co-occurring, adverse effects have already been described in primary studies [21,29]. We detected a combined occurrence of the physical parameter temperature rise under the mask with the symptom respiratory impairment in seven of the nine studies concerned (88%). We found a similar result for the decrease in oxygen saturation under mask and the symptom respiratory impairment with a simultaneous detection in six of the eight studies concerned (67%). We detected a combined occurrence of carbon dioxide rise under N95 mask use in nine of the 11 scientific papers (82%). We found a similar result for oxygen drop under N95 mask use with simultaneous co-occurrence in eight of 11 primary papers (72%). The use of N95 masks was also associated with headache in six of the 10 primary studies concerned (60%). A combined occurrence of the physical parameters temperature rise and humidity under masks was even found 100% within six of the six studies with significant measurements of these parameters (Figure 2). Since the symptoms were described in combination in mask wearers and were not observed in isolation in the majority of cases, we refer to them as general Mask-Induced Exhaustion Syndrome (MIES) because of the consistent presentation in numerous papers from different disciplines. These include the following, predominantly statistically significantly (p < 0.05) proven pathophysiological changes and subjective complaints, which often occur in combination as described above (see also Section 3.1 to Section 3.11, Figure 2, Figure 3 and Figure 4):  Figura 4. Efectos desfavorables de la máscara como componentes del síndrome de agotamiento inducido por máscara (MIES). Los efectos químicos, físicos y biológicos, así como las consecuencias del sistema orgánico mencionadas, están todos documentados con resultados estadísticamente significativos en la literatura científica encontrada ( Figura 2 ). El término somnolencia se utiliza aquí para resumir cualquier déficit neurológico cualitativo descrito en la literatura científica examinada. - Increase in dead space volume [22,24,58,59] (Figure 3, Section 3.1 and Section 3.2). - Increase in breathing resistance [31,35,61,118] (Figure 3, Figure 2: Column 8). - Increase in blood carbon dioxide [13,15,19,21,22,23,24,25,26,27,28] (Figure 2: Column 5). - Decrease in blood oxygen saturation [18,19,21,23,28,29,30,31,32,33,34] (Figure 2: Column 4). - Increase in heart rate [15,19,23,29,30,35] (Figure 2: Column 12). - Decrease in cardiopulmonary capacity [31] (Section 3.2).

En individuos propensos al pánico, la activación simpática noradrenérgica inductora de estrés puede estar mediada en parte directamente a través del mecanismo del dióxido de carbono (CO 2 ) en el locus coeruleus en el tronco encefálico [ 39 , 78 , 79 , 153 ], pero también de la forma habitual a través de neuronas quimio-sensibles del núcleo solitario en la médula [ 136 , 154 ]. El núcleo solitario [ 136 ] se encuentra en la parte más profunda del tronco encefálico, una puerta de entrada al control neuronal respiratorio y circulatorio [ 154 ]. Una disminución del nivel de oxígeno (O 2 ) en sangre provoca la activación del eje simpático a través de quimiorreceptores en las carótidas [155 , 156 ]. Incluso los cambios por debajo del umbral de los gases en sangre, como los que se producen al llevar una máscara, provocan reacciones en estos centros de control del sistema nervioso central. Por tanto, las máscaras desencadenan reacciones directas en importantes centros de control del cerebro afectado a través de los más mínimos cambios de oxígeno y dióxido de carbono en la sangre del usuario [ 136 , 154 , 155 ]. Se ha demostrado científicamente un vínculo entre las alteraciones de la respiración y las enfermedades cardiorrespiratorias como la hipertensión, la apnea del sueño y el síndrome metabólico [ 56 , 57 ]. Curiosamente, la disminución de los niveles de oxígeno / O 2 en sangre y también el aumento de los niveles de dióxido de carbono / CO 2 en sangre se consideran los principales desencadenantes de la respuesta al estrés simpático [ 38 , 136 ]. Las mencionadas neuronas quimiosensibles del núcleo solitario en la médula se consideran los principales centros de control responsables [ 136 , 154 , 155]. Los efectos clínicos del uso prolongado de mascarillas serían, por tanto, una posible intensificación de las reacciones de estrés crónico e influencias negativas sobre el metabolismo que conducen a un síndrome metabólico. Los estudios de máscaras que encontramos muestran que tales cambios de gases respiratorios relevantes para la enfermedad (O 2 y CO 2 ) [ 38 , 136 ] ya se logran usando una máscara [ 13 , 15 , 18 , 19 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30, 31 , 32 , 33 , 34 ]. Se conoce científicamente una conexión entre la hipoxia, las reacciones simpáticas y la liberación de leptina [ 136 ]. Additionally important is the connection of breathing with the influence on other bodily functions [56,57], including the psyche with the generation of positive emotions and drive [153]. The latest findings from neuro-psychobiological research indicate that respiration is not only a function regulated by physical variables to control them (feedback mechanism), but rather independently influences higher-level brain centers and, thus, also helps to shape psychological and other bodily functions and reactions [153,157,158]. Since masks impede the wearer’s breathing and accelerate it, they work completely against the principles of health-promoting breathing [56,57] used in holistic medicine and yoga. According to recent research, undisturbed breathing is essential for happiness and healthy drive [157,159], but masks work against this. The result of significant changes in blood gases in the direction of hypoxia (drop in oxygen saturation) and hypercapnia (increase in carbon dioxide concentration) through masks, thus, has the potential to have a clinically relevant influence on the human organism even without exceeding normal limits. According to the latest scientific findings, blood-gas shifts towards hypoxia and hypercapnia not only have an influence on the described immediate, psychological and physiological reactions on a macroscopic and microscopic level, but additionally on gene expression and metabolism on a molecular cellular level in many different body cells. Through this, the drastic disruptive intervention of masks in the physiology of the body also becomes clear down to the cellular level, e.g., in the activation of hypoxia-induced factor (HIF) through both hypercapnia and hypoxia-like effects [160].

Neither higher level institutions such as the WHO or the European Centre for Disease Prevention and Control (ECDC) nor national ones, such as the Centers for Disease Control and Prevention, GA, USA (CDC) or the German RKI, substantiate with sound scientific data a positive effect of masks in the public (in terms of a reduced rate of spread of COVID-19 in the population) [2,4,5]. Contrary to the scientifically established standard of evidence-based medicine, national and international health authorities have issued their theoretical assessments on the masks in public places, even though the compulsory wearing of masks gives a deceptive feeling of safety [5,112,143]. From an infection epidemiological point of view, masks in everyday use offer the risk of self-contamination by the wearer from both inside and outside, including via contaminated hands [5,16,88]. In addition, masks are soaked by exhaled air, which potentially accumulates infectious agents from the nasopharynx and also from the ambient air on the outside and inside of the mask. In particular, serious infection-causing bacteria and fungi should be mentioned here [86,88,89], but also viruses [87]. The unusual increase in the detection of rhinoviruses in the sentinel studies of the German RKI from 2020 [90] could be an indication of this phenomenon. Clarification through further investigations would therefore be desirable. Masks, when used by the general public, are considered by scientists to pose a risk of infection because the standardized hygiene rules of hospitals cannot be followed by the general public [5]. On top of that, mask wearers (surgical, N95, fabric masks) exhale relatively smaller particles (size 0.3 to 0.5 μm) than mask-less people and the louder speech under masks further amplifies this increased fine aerosol production by the mask wearer (nebulizer effect) [98]. The history of modern times shows that already in the influenza pandemics of 1918–1919, 1957–58, 1968, 2002, in SARS 2004–2005 as well as with the influenza in 2009, masks in everyday use could not achieve the hoped-for success in the fight against viral infection scenarios [67,144]. The experiences led to scientific studies describing as early as 2009 that masks do not show any significant effect with regard to viruses in an everyday scenario [129,145]. Even later, scientists and institutions rated the masks as unsuitable to protect the user safely from viral respiratory infections [137,146,147]. Even in hospital use, surgical masks lack strong evidence of protection against viruses [67]. Originally born out of the useful knowledge of protecting wounds from surgeons’ breath and predominantly bacterial droplet contamination [144,148,149], the mask has been visibly misused with largely incorrect popular everyday use, particularly in Asia in recent years [150]. Significantly, the sociologist Beck described the mask as a cosmetic of risk as early as 1992 [151]. Unfortunately, the mask is inherent in a vicious circle: strictly speaking, it only protects symbolically and at the same time represents the fear of infection. This phenomenon is reinforced by the collective fear mongering, which is constantly nurtured by main stream media [137]. Nowadays, the mask represents a kind of psychological support for the general population during the virus pandemic, promising them additional anxiety-reduced freedom of movement. The recommendation to use masks in the sense of “source control” not out of self-protection but out of “altruism” [152] is also very popular with the regulators as well as the population of many countries. The WHO’s recommendation of the mask in the current pandemic is not only a purely infectiological approach, but is also clear on the possible advantages for healthy people in the general public. In particular, a reduced potential stigmatization of mask wearers, the feeling of a contribution made to preventing the spread of the virus, as well as the reminder to adhere to other measures are mentioned [2].

Not only do they absorb nanoparticles such as viruses [6], but they also follow the airflow when inhaling and exhaling, causing them to be carried further. In addition, a physical decay process has been described for aerosol droplets at increasing temperatures, as also occurs under a mask [15,44,85]. This process can lead to a decrease in size of the fine water droplets up to the diameter of a virus [121,122]. The masks filter larger aerosol droplets but cannot retain viruses themselves and such smaller, potentially virus-containing aerosol droplets of less than 0.2 μm and hence cannot stop the spread of virus [123]. Similarly, in an in vivo comparative studies of N95 and surgical masks, there were no significant differences in influenza virus infection rates [124,125]. Although this contrasts with encouraging in vitro laboratory results with virus-free aerosols under non-natural conditions, even with fabric masks [126], it should be noted that under natural in-vivo conditions, the promising filtration functions of fabric masks based on electrostatic effects also rapidly diminish under increasing humidity [127]. A Swiss textile lab test of various masks available on the market to the general public recently confirmed that most mask types filter aerosols insufficiently. For all but one of the eight reusable fabric mask types tested, the filtration efficacy according to EN149 was always less than 70% for particles of 1 μm in size. For disposable masks, only half of all eight mask types tested were efficient enough at filtering to retain 70% of particles 1 μm in size [128]. Un estudio experimental reciente incluso demostró que todas las personas que usan mascarillas (quirúrgicas, N95, mascarillas de tela) liberan en el aire partículas significativa y proporcionalmente más pequeñas de un tamaño de 0,3 a 0,5 μm que las personas sin mascarilla, tanto al respirar, hablar y toser [ 98 ]. Según esto, las máscaras actúan como nebulizadores y contribuyen a la producción de aerosoles muy finos. Sin embargo, las partículas más pequeñas se propagan más rápido y más lejos que las grandes por razones físicas. De particular interés en este estudio de referencia experimental fue el hallazgo de que un sujeto de prueba que usaba una máscara de tela de una sola capa también podía liberar un total de 384% más de partículas (de varios tamaños) al respirar que una persona sin [ 98 ]. No son solo las debilidades funcionales mencionadas anteriormente de las propias máscaras las que conducen a problemas, sino también su uso. Esto aumenta el riesgo de una falsa sensación de seguridad. De acuerdo con la literatura, tanto los trabajadores de la salud como los legos cometen errores al usar máscaras, ya que el uso de máscaras higiénicamente correcto no es de ninguna manera intuitivo. En general, el 65% de los profesionales sanitarios y hasta el 78% de la población general utilizan mascarillas de forma incorrecta [ 116 ]. Tanto con las máscaras quirúrgicas como con las máscaras N95, el cumplimiento de las reglas de uso se ve afectado y no se sigue adecuadamente debido a la reducción de la capacidad de uso con molestias por el calor e irritación de la piel [ 29 , 35 , 116 , 129]. Esto se ve agravado por la acumulación de dióxido de carbono debido al espacio muerto (especialmente debajo de las máscaras N95) con los dolores de cabeza resultantes descritos [ 19 , 27 , 37 , 66 , 67 , 68 , 83 ]. Aumento de la frecuencia cardíaca, picazón y sensación de humedad [ 15 , 29 , 30 , 35 , 71] también conducen a una reducción de la seguridad y la calidad durante el uso (véanse también los efectos secundarios y los peligros sociales y de salud ocupacional). Por ello, las mascarillas (cotidianas) se consideran incluso un riesgo generalizado de contagio en la población general, lo que no se acerca a imitar las estrictas normas de higiene de los hospitales y consultorios médicos: la supuesta seguridad, por tanto, se convierte en un riesgo de seguridad en sí mismo. [ 5 ].

These include the professional masks of the surgical mask type and N95/KN95 (FFP2 equivalent) that are commonly used in everyday life, but also the community fabric masks that were initially used. In the case of N95, the N stands for National Institute for Occupational Safety and Health of the United States (NIOSH), and 95 indicates the 95 per cent filtering capacity for fine particles up to at least 0.3 μm [82]. A major risk of mask use in the general public is the creation of a false sense of security with regard to protection against viral infections, especially in the sense of a falsely assumed strong self-protection. Disregarding infection risks may not only neglect aspects of source control, but also result in other disadvantages. Although there are quite a few professional positive accounts of the widespread use of masks in the general populace [111], most of the serious and evident scientific reports conclude that the general obligation to wear masks conveys a false sense of security [4,5]. However, this leads to a neglect of those measures that, according to the WHO, have a higher level of effectiveness than mask-wearing: social distancing and hand hygiene [2,112]. Researchers were able to provide statistically significant evidence of a false sense of security and more risky behavior when wearing masks in an experimental setting [112]. Decision makers in many countries informed their citizens early on in the pandemic in March 2020 that people without symptoms should not use a medical mask, as this created a false sense of security [113]. The recommendation was ultimately changed in many countries. At least Germany pointed out that wearers of certain types of masks such as the common fabric masks (community masks) cannot rely on them to protect them or others from transmission of SARS-CoV-2 [114]. However, scientists not only complain about the lack of evidence for fabric masks in the scope of a pandemic [16,110], but also about the high permeability of fabric masks with particles and the potential risk of infection they pose [108,109]. Ordinary fabric masks with a 97% penetration for particle dimensions of ≥0.3 μm are in stark contrast to medical-type surgical masks with a 44% penetration. In contrast, the N95 mask has a penetration rate of less than 0.01% for particles ≥ 0.3 μm in the laboratory experiment [108,115]. For the clinical setting in hospitals and outpatient clinics, the WHO guidelines recommend only surgical masks for influenza viruses for the entire patient treatment except for the strongly aerosol-generating measures, for which finer filtering masks of the type N95 are suggested. However, the WHO’s endorsement of specific mask types is not entirely evidence-based due to the lack of high-quality studies in the health sector [108,109,116,117]. In a laboratory experiment (evidence level IIa study), it was demonstrated that both surgical masks and N95 masks have deficits in protection against SARS-CoV-2 and influenza viruses using virus-free aerosols [118]. In this study, the FFP2-equivalent N95 mask performed significantly better in protection (8–12 times more effective) than the surgical mask, but neither mask type established reliable, hypothesis-generated protection against corona and influenza viruses. Both mask types could be penetrated unhindered by aerosol particles with a diameter of 0.08 to 0.2 μm. Both the SARS-CoV-2 pathogens with a size of 0.06 to 0.14 μm [119] and the influenza viruses with 0.08 to 0.12 μm are unfortunately well below the mask pore sizes [118]. The filtering capacity of the N95 mask up to 0.3 μm [82] is usually not achieved by surgical masks and community masks. However, aerosol droplets, which have a diameter of 0.09 to 3 μm in size, are supposed to serve as a transport medium for viruses. These also penetrate the medical masks by 40%. Often, there is also a poor fit between the face and the mask, which further impairs their function and safety [120]. The accumulation of aerosol droplets on the mask is problematic.

A decrease in empathy perception through mask use with disruption of the doctor–patient relationship has already been scientifically proven on the basis of a randomized study (statistically significant, with p = 0.04) [99]. In this study, the Consultation Empathy Care Measury, the Patient Enablement Instrument (PEI) Score and a Satisfaction Rating Scale were assessed in 1030 patients. The 516 doctors, who wore masks throughout, conveyed reduced empathy towards the patients and, thus, nullified the positive health-promoting effects of a dynamic relationship. These results demonstrate a disruption of interpersonal interaction and relationship dynamics caused by masks. The WHO guidance on the use of masks in children in the community, published in August 2020, points out that the benefits of mask use in children must be weighed up against the potential harms, including social and communicational concerns [100]. Fears that widespread pandemic measures will lead to dysfunctional social life with degraded social, cultural and psychological interactions have also been expressed by other experts [6,7,8,42]. 3.11. Social and Occupational Medicine Side Effects and Hazards In addition to mask-specific complaints such as a feeling of heat, dampness, shortness of breath and headache, various physiological phenomena were documented, such as the significant increase in heart and respiratory rate, the impairment of lung function parameters, the decrease in cardiopulmonary capacity (e.g., lower maximum blood lactate response) [15,19,21,23,29,30,31], as well as the changes in oxygen and carbon dioxide both in the end-expiratory and the air under the mask that was measured in the blood of the individuals [13,15,18,19,21,22,23,24,25,27,28,29,30,31,32,33,34]. The significant changes were measurable after only a few minutes of wearing a mask and in some cases reached magnitudes of minus 13% reduced O2 concentration and 30-fold increased CO2 concentration of the inhaled air under masks (p < 0.001) [18]. The changes observed were not only statistically significant, but also clinically relevant; the subjects also showed pathological oxygen saturation after exposure to masks (p < 0.02) [18]. Shortness of breath during light exertion (6 min walking) under surgical masks has been recorded with statistical significance in 44 healthy subjects in a prospective experimental intervention study (p < 0.001) [101]. Here, the complaints were assessed using a subjective, visual analogue scale. In another study from 2011, all tested masks caused a significantly measurable increase in discomfort and a feeling of exhaustion in the 27 subjects during prolonged usage (p < 0.0001) [69]. These symptoms lead to additional stress for the occupational mask wearer and, thus, in relation to the feeling of exhaustion, contribute to the self-perpetuating vicious circle caused by the vegetative sympathetic activation, which further increases the respiratory and heart rate, blood pressure and increased sense of exhaustion [16,20,35,83]. Other studies showed that the psychological and physical effects of the masks can lead to an additional reduction in work performance (measured with the Roberge Subjective Symptoms-during-Work Scale, a Likert scale of 1–5) via increased feelings of fatigue, dissatisfaction and anxiety [58,102,103]. Wearing masks over a longer period of time also led to physiological and psychological impairments in other studies and, thus, reduced work performance [19,36,58,69]. In experiments on respiratory-protective equipment, an increase in the dead space volume by 350 mL leads to a reduction in the possible performance time by approx. −19%, furthermore to a decrease in breathing comfort by −18% (measured via a subjective rating scale) [58]. In addition, the time spent working and the flow of work is interrupted and reduced by putting on and taking off the masks and changing them.

De hecho, la retención de CO 2 inducida por el espacio muerto mientras se usa una máscara durante el ejercicio también fue probada experimentalmente. Los efectos de un ejercicio aeróbico corto con máscaras N95 se probaron en 16 voluntarios sanos. Se encontró un aumento significativo de la presión parcial al final de la espiración de dióxido de carbono (PETCO 2 ) con más de 8 mmHg ( p <0,001) [ 24 ]. El aumento de dióxido de carbono (CO 2 ) en sangre en los usuarios de mascarillas bajo carga máxima fue más un 14% de CO 2 para las mascarillas quirúrgicas y más un 23% de CO 2 para las mascarillas N95, un efecto que bien puede tener relevancia clínica en los predinferidos, ancianos y niños, ya que estos valores se acercaron fuertemente al rango patológico [ 24]. En un interesante estudio de resistencia con ocho sujetos de mediana edad (19-66), se determinó el contenido de gas para O 2 y CO 2 debajo de las máscaras antes y después del ejercicio. Incluso en reposo, la disponibilidad de oxígeno debajo de las máscaras fue un 13% menor que sin las máscaras y la concentración de dióxido de carbono (CO 2 ) fue 30 veces mayor. Bajo estrés (prueba de Ruffier), la concentración de oxígeno (% O 2 ) por debajo de la máscara se redujo significativamente en un 3,7% adicional, mientras que la concentración de dióxido de carbono (% CO 2 ) aumentó significativamente en un 20% adicional (estadísticamente significativo con p <0,001 ). En consecuencia, la saturación de oxígeno de la sangre (SpO 2) de las personas de prueba también disminuyó significativamente del 97,6 al 92,1% ( p <0,02) [ 18 ]. La caída del valor de saturación de oxígeno (SpO 2 ) al 92%, claramente por debajo del límite normal del 95%, debe clasificarse como clínicamente relevante y perjudicial para la salud. Estos hechos son una indicación de que el uso de máscaras también desencadena los efectos descritos anteriormente que conducen a la hipoxia e hipercapnia en los deportes. En consecuencia, la OMS y los Centros para el Control y la Prevención de Enfermedades de GA, EE.UU. (CDC) desaconsejan el uso de máscaras durante el ejercicio físico [ 82 , 97 ]. 3.10. Efectos secundarios y peligros sociales y sociológicos Los resultados de un estudio chileno con trabajadores de la salud muestran que las máscaras actúan como un filtro acústico y provocan un habla excesivamente alta. Esto provoca un trastorno de la voz [ 43 ]. El aumento del volumen del habla también contribuye a una mayor producción de aerosoles por parte del usuario de la máscara [ 98 ]. Estos datos experimentales medidos con el medidor de partículas aerodinámicas (APS, TSI, modelo 332, TSI Incorporated, Minnesota, MI, EE. UU.) Son muy relevantes. Además, los usuarios de máscaras no pueden interactuar normalmente en la vida cotidiana debido a la alteración de la claridad del habla [ 45 ], lo que los tienta a acercarse unos a otros. This results in a distorted prioritization in the general public, which counteracts the recommended measures associated with the COVID-19 pandemic. The WHO prioritizes social distancing and hand hygiene with moderate evidence and recommends wearing a mask with weak evidence, especially in situations where individuals are unable to maintain a physical distance of at least 1 m [3]. The disruption of non-verbal communication due to the loss of facial expression recognition under the mask can increase feelings of insecurity, discouragement and numbness as well as isolation, which can be extremely stressful for the mentally and hearing-impaired [16]. Experts point out that masks disrupt the basics of human communication (verbal and nonverbal). The limited facial recognition caused by masks leads to a suppression of emotional signals. Masks, therefore, disrupt social interaction, erasing the positive effect of smiles and laughter but at the same time greatly increasing the likelihood of misunderstandings because negative emotions are also less evident under masks [42].

An additional suitability examination by specialized physicians is also obligatory and stipulated for occupationally used respirators [104]. 3.12. Microbiological Consequences for Wearer and Environment: Foreign/Self-Contamination Masks cause retention of moisture [61]. Poor filtration performance and incorrect use of surgical masks and community masks, as well as their frequent reuse, imply an increased risk of infection [108,109,110]. The warm and humid environment created by and in masks without the presence of protective mechanisms such as antibodies, the complement system, defense cells and pathogen-inhibiting and on a mucous membrane paves the way for unimpeded growth and, thus, an ideal growth and breeding ground for various pathogens such as bacteria and fungi [88] and also allows viruses to accumulate [87]. The warm and humid mask microclimate favors the accumulation of various germs on and underneath the masks [86], and the germ density is measurably proportional to the length of time the mask is worn. After only 2 h of wearing the mask, the pathogen density increases almost tenfold in experimental observation studies [87,89]. From a microbiological and epidemiological point of view, masks in everyday use pose a risk of contamination. This can occur as foreign contamination but also as self-contamination. On the one hand, germs are sucked in or attach themselves to the masks through convection currents. On the other hand, potential infectious agents from the nasopharynx accumulate excessively on both the outside and inside of the mask during breathing [5,88]. This is compounded by contact with contaminated hands. Since masks are constantly penetrated by germ-containing breath and the pathogen reproduction rate is higher outside mucous membranes, potential infectious pathogens accumulate excessively on the outside and inside of masks. On and in the masks, there are quite serious, potentially disease-causing bacteria and fungi such as E. coli (54% of all germs detected), Staphylococcus aureus (25% of all germs detected), Candida (6%), Klebsiella (5%), Enterococci (4%), Pseudomonads (3%), Enterobacter (2%) and Micrococcus (1%) even detectable in large quantities [88]. In another microbiological study, the bacterium Staphylococcus aureus (57% of all bacteria detected) and the fungus Aspergillus (31% of all fungi detected) were found to be the dominant germs on 230 surgical masks examined [86]. After more than six hours of use, the following viruses were found in descending order on 148 masks worn by medical personnel: adenovirus, bocavirus, respiratory syncytial virus and influenza viruses [87]. From this aspect, it is also problematic that moisture distributes these potential pathogens in the form of tiny droplets via capillary action on and in the mask, whereby further proliferation in the sense of self- and foreign contamination by the aerosols can then occur internally and externally with every breath [35]. In this regard, it is also known from the literature that masks are responsible for a proportionally disproportionate production of fine particles in the environment and, surprisingly, much more so than in people without masks [98]. It was shown that all mask-wearing subjects released significantly more smaller particles of size 0.3–0.5 μm into the air than mask-less people, both when breathing, speaking and coughing (fabric, surgical, N95 masks, measured with the Aerodynamic Particle Sizer, APS, TS, model 3329) [98]. The increase in the detection of rhinoviruses in the sentinel studies of the German RKI from 2020 [90] could be a further indication of this phenomenon, as masks were consistently used by the general population in public spaces in that year. 3.13. Epidemiological Consequences The possible side effects and dangers of masks described in this paper are based on studies of different types of masks.

Los médicos otorrinolaringólogos descubrieron recientemente una nueva forma de rinitis irritante debido al uso de la mascarilla N95 en 46 pacientes. Realizaron endoscopias e irrigaciones nasales a los portadores de mascarillas, que posteriormente fueron evaluadas patológicamente. Los problemas clínicos se registraron con cuestionarios estandarizados. Encontraron evidencia estadísticamente significativa de rinitis inducida por máscara y picazón e hinchazón de las membranas mucosas, así como un aumento de los estornudos ( p <0.01). Endoscópicamente, mostró un aumento de la secreción y evidencia de fibras de polipropileno de la máscara inhalada como desencadenante de la irritación de la mucosa [ 96 ]. En un estudio de 221 trabajadores de la salud, los otorrinolaringólogos objetivaron un trastorno de la voz en el 33% de los usuarios de mascarillas. La puntuación VHI-10 de 1 a 10, que mide los trastornos de la voz, fue en promedio 5,72 más alta en estos usuarios de mascarillas (estadísticamente significativa con p <0,001). La máscara no sólo actuó como un filtro acústico, provocando un habla excesivamente alta, sino que también parece desencadenar una coordinación deficiente de las cuerdas vocales porque la máscara compromete los gradientes de presión necesarios para un habla sin perturbaciones [ 43 ]. Los investigadores concluyeron a partir de sus hallazgos que las máscaras podrían representar un riesgo potencial de desencadenar nuevos trastornos de la voz y de exacerbar los existentes. 3.9. Efectos secundarios y peligros de la medicina deportiva De acuerdo con la literatura, no se pueden probar los efectos de mejora del rendimiento de las máscaras con respecto a la optimización cardiovascular y la mejora de la capacidad de absorción de oxígeno. Por ejemplo, en un estudio de referencia experimental (12 sujetos por grupo), la máscara de entrenamiento que supuestamente imita el entrenamiento en altitud (ETM: máscara de entrenamiento en elevación) solo tuvo efectos de entrenamiento en los músculos respiratorios. Sin embargo, los usuarios de mascarilla mostraron valores de saturación de oxígeno significativamente más bajos (SpO 2 %) durante el ejercicio (SpO 2 del 94% para los usuarios de mascarilla versus 96% para los que no usaban mascarilla, p <0,05) [ 33 ], lo que puede explicarse por un aumento de las muertes volumen del espacio y mayor resistencia durante la respiración. Los valores de saturación de oxígeno medidos fueron significativamente más bajos que los valores normales en el grupo de usuarios de máscara, lo que indica una relevancia clínica. El efecto de adaptación probado de los músculos respiratorios en atletas sanos [ 33 ] sugiere claramente que las máscaras tienen un efecto perturbador en la fisiología respiratoria. En otro estudio de intervención sobre el uso de mascarillas en levantadores de pesas, los investigadores documentaron efectos estadísticamente significativos de la atención reducida (registro del cuestionario, escala Likert) y una velocidad máxima de movimiento más lenta detectable por medio de sensores (ambos significativos ap <0,001), lo que llevó a los investigadores a concluyen que el uso de mascarillas en el deporte no está exento de riesgos. Como hallazgo secundario, también detectaron una disminución significativa en la saturación de oxígeno SpO 2 al realizar ejercicios especiales de levantamiento de pesas (“sentadillas hacia atrás”) en el grupo de máscara después de solo 1 minuto de ejercicio en comparación con el grupo sin máscara ( p <0,001 ) [ 32 ]. La probada tendencia de las máscaras a cambiar el parámetro químico saturación de oxígeno SpO 2 en una dirección patológica (valor límite inferior 95%) bien puede tener relevancia clínica en individuos no entrenados o enfermos. La medicina deportiva confirmó un aumento de la retención de dióxido de carbono (CO 2 ), con una elevación de la presión parcial de CO 2 en la sangre con mayores volúmenes de espacio muerto respiratorio [ 14 ].

The reduced work performance has been recorded in the literature found as described above (especially in Section 3.1 and Section 3.2) but has not been quantified further in detail [36,58]. Surgical mask type and N95 protective equipment frequently caused adverse effects in medical personnel such as headaches, breathing difficulties, acne, skin irritation, itching, decreased alertness, decreased mental performance and feelings of dampness and heat [19,29,37,71,85]. Subjective, work performance-reducing, mask-related impairments in users, measured with special survey scores and Likert scales, have also been described in other studies [15,21,27,32,35,43,66,67,68,72,96,99]. In Section 3.7 on dermatology, we already mentioned a paper that demonstrated a significant temperature increase of 1.9 °C on average (to over 34.5 °C) in the mask-covered facial area (p < 0.05) [85]. Due to the relatively larger representation in the sensitive cerebral cortex (homunculus), the temperature sensation in the face is more decisive for the feeling of well-being than other body regions [36,44]. The perception of discomfort when wearing a mask can, thus, be intensified. Interestingly, in our analysis, we found a combined occurrence of the physical variable temperature rise under the mask and the symptom respiratory impairment in seven of eight studies concerned, with a mutual significantly measured occurrence in 88%. We also detected a combined occurrence of significantly measured temperature rise under the mask and significantly measured fatigue in 50% of the relevant primary studies (three of six papers, Figure 2). These clustered associations of temperature rise with symptoms of respiratory impairment and fatigue suggest a clinical relevance of the detected temperature rise under masks. In the worst case scenario, the effects mentioned can reinforce each other and lead to decompensation, especially in the presence of COPD, heart failure and respiratory insufficiency. The sum of the disturbances and discomforts that can be caused by a mask also contributes to distraction (see also psychological impairment). These, in conjunction with a decrease in psycho-motoric skills, reduced responsiveness and overall impaired cognitive performance (all of which are pathophysiological effects of wearing a mask) [19,29,32,39,40,41] can lead to a failure to recognize hazards and, thus, to accidents or avoidable errors at work [19,36,37]. Of particular note here are mask-induced listlessness (p < 0.05), impaired thinking (p < 0.05) and concentration problems (p < 0.02) as measured by a Likert scale (1–5) [29]. Accordingly, occupational health regulations take action against such scenarios. The German Industrial Accident Insurance (DGUV) has precise and extensive regulations for respiratory protective equipment where they document the limitation of wearing time, levels of work intensity and defined instruction obligation [104]. The standards and norms prescribed in many countries regarding different types of masks to protect their workers are also significant from an occupational health point of view [105]. In Germany, for example, there are very strict safety specifications for masks from other international countries. These specify the requirements for the protection of the wearer [106]. All these standards and the accompanying certification procedures were increasingly relaxed with the introduction of mandatory masks for the general public. This meant that non-certified masks such as community masks were also used on a large scale in the work and school sectors for longer periods during the pandemic measures [107]. Most recently, in October 2020, the German Social Accident Insurance (DGUV) recommended the same usage time limits for community masks as for filtering half masks, namely, a maximum of three shifts of 120 min per day with recovery breaks of 30 min in between. In Germany, FFP2 (N95) masks must be worn for 75 min, followed by a 30-minute break.

En un metaanálisis de nivel de evidencia Ia encargado por la OMS, no se pudo demostrar ningún efecto de las mascarillas en el contexto de la prevención de la pandemia del virus de la influenza [ 130 ]. En 14 ensayos controlados aleatorios, no se demostró una reducción en la transmisión de infecciones por influenza confirmadas por laboratorio. Debido al tamaño similar y las vías de distribución de las especies de virus (influenza y Corona, ver arriba), los datos también se pueden transferir al SARS-CoV-2 [ 118 ]. No obstante, una combinación de uso ocasional de mascarillas con un adecuado lavado de manos provocó una ligera reducción de las infecciones por influenza en un estudio [ 131]. Sin embargo, dado que en este estudio no se logró separar la higiene de las manos y las máscaras, el efecto protector puede atribuirse más bien a la higiene de las manos en vista de los datos antes mencionados [ 131 ]. Un gran estudio prospectivo comparativo danés publicado recientemente que comparó a los usuarios de mascarillas con los que no los usaban en términos de sus tasas de infección con el SARS-CoV2 no pudo demostrar diferencias estadísticamente significativas entre los grupos [ 132 ]. 3.14. Efectos secundarios y peligros pediátricos Children are particularly vulnerable and may be more likely to receive inappropriate treatment or additional harm. It can be assumed that the potential adverse mask effects described for adults are all the more valid for children (see Section 3.1 to Section 3.13: physiological internal, neurological, psychological, psychiatric, dermatological, ENT, dental, sociological, occupational and social medical, microbiological and epidemiological impairments and also Figure 2 and Figure 3). Special attention must be paid to the respiration of children, which represents a critical and vulnerable physiological variable due to higher oxygen demand, increased hypoxia susceptibility of the CNS, lower respiratory reserve, smaller airways with a stronger increase in resistance when the lumen is narrowed. The diving reflex caused by stimulating the nose and upper lip can cause respiratory arrest to bradycardia in the event of oxygen deficiency. The masks currently used for children are exclusively adult masks manufactured in smaller geometric dimensions and had neither been specially tested nor approved for this purpose [133]. In an experimental British research study, the masks frequently led to feelings of heat (p < 0.0001) and breathing problems (p < 0.03) in 100 school children between 8 and 11 years of age especially during physical exertion, which is why the protective equipment was taken off by 24% of the children during physical activity [133]. The exclusion criteria for this mask experiment were lung disease, cardiovascular impairment and claustrophobia [133]. Scientists from Singapore were able to demonstrate in their level Ib study published in the renowned journal “nature” that 106 children aged between 7 and 14 years who wore FFP2 masks for only 5 min showed an increase in the inspiratory and expiratory CO2 levels, indicating disturbed respiratory physiology [26]. However, a disturbed respiratory physiology in children can have long-term disease-relevant consequences. Slightly elevated CO2 levels are known to increase heart rate, blood pressure, headache, fatigue and concentration disorders [38]. Accordingly, the following conditions were listed as exclusion criteria for mask use [26]: any cardiopulmonary disease including but not limited to: asthma, bronchitis, cystic fibrosis, congenital heart disease, emphysema; any condition that may be aggravated by physical exertion, including but not limited to: exercise-induced asthma; lower respiratory tract infections (pneumonia, bronchitis within the last 2 weeks), anxiety disorders, diabetes, hypertension or epilepsy/attack disorder; any physical disability due to medical, orthopedic or neuromuscular disease; any acute upper respiratory illness or symptomatic rhinitis (nasal obstruction, runny nose or sneezing); any condition with deformity that

corteza cerebral sensible (homúnculo) [ 36 ]. Según un cuestionario, las máscaras también causan con frecuencia reacciones de ansiedad y estrés psicovegetativo en los niños, así como en los adultos, con un aumento de las enfermedades psicosomáticas y relacionadas con el estrés y de la autoexperiencia depresiva, menor participación, aislamiento social y disminución de la salud. -cuidado personal [ 74 ]. Más del 50% de los usuarios de mascarillas estudiados tenían al menos sentimientos depresivos leves [ 74 ]. Una cobertura mediática adicional que induce al miedo y a menudo exagerada puede intensificar esto aún más. Un análisis retrospectivo reciente de los medios de comunicación en general en el contexto de la epidemia de ébola de 2014 mostró un contenido de verdad científica de solo el 38% de toda la información publicada públicamente [ 75]. Los investigadores clasificaron un total del 28% de la información como provocativa y polarizante y el 42% como riesgos exagerados. Además, el 72% del contenido de los medios tenía como objetivo suscitar sentimientos negativos relacionados con la salud. El sentimiento de miedo, combinado con la inseguridad y la necesidad humana primordial de pertenecer [ 76 ], provoca una dinámica social que parece en parte infundada desde un punto de vista médico y científico. La máscara, que originalmente tenía un propósito puramente higiénico, se ha transformado en un símbolo de conformidad y pseudo-solidaridad. La OMS, por ejemplo, enumera las ventajas del uso de máscaras por personas sanas en público para incluir una estigmatización potencialmente reducida de los usuarios de máscaras, un sentido de contribución a la prevención de la propagación del virus y un recordatorio para cumplir con otras medidas [ 2 ]. 3.5. Efectos secundarios psiquiátricos y peligros Como se explicó anteriormente, las mascarillas pueden causar un aumento de la reinhalación con una acumulación de dióxido de carbono en el usuario debido al aumento del volumen del espacio muerto [ 16 , 17 , 18 , 20 ] ( Figura 3 ), con un elevado nivel de dióxido de carbono (CO2) en sangre medible a menudo estadísticamente significativo niveles en los pacientes [ 13 , 15 , 17 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ] ( Figura 2). Sin embargo, se sabe que los cambios que conducen a la hipercapnia desencadenan ataques de pánico [ 77 , 78 ]. Esto hace que el aumento significativamente medible de CO 2 causado por el uso de una mascarilla sea clínicamente relevante. Curiosamente, las pruebas de provocación respiratoria mediante la inhalación de CO 2 se utilizan para diferenciar los estados de ansiedad en los trastornos de pánico y la disforia premenstrual de otros cuadros clínicos psiquiátricos. En este caso, las concentraciones absolutas de CO 2 al 5% ya son suficientes para desencadenar reacciones de pánico en 15-16 min [ 77 ]. El contenido normal de aire exhalado de CO 2 es aproximadamente del 4%. Es obvio a partir de estudios experimentales en sujetos enmascarados que podrían ocurrir cambios de concentración en los gases respiratorios en el rango mencionado anteriormente con valores superiores al 4% durante la reinspiración con el uso prolongado de mascarillas [ 18 , 23 ]. La activación del locus coeruleus por el CO 2 se utiliza para generar reacciones de pánico a través de los gases respiratorios [ 78 , 79 ]. Esto se debe a que el locus coeruleus es una parte importante del sistema de neuronas noradrenérgicas vegetativas, un centro de control en el tallo cerebral, que reacciona a un estímulo apropiado y a cambios en las concentraciones de gas en la sangre liberando la hormona del estrés noradrenalina [ 78 ]. De los peligros y efectos secundarios fisiológicos, neurológicos y psicológicos descritos anteriormente ( Sección 3.1 , Sección 3.3 y Sección 3.4 ), se pueden derivar problemas adicionales para el uso de máscaras en casos psiquiátricos. Las personas que se someten a tratamiento para la demencia, la esquizofrenia paranoide, los trastornos de la personalidad con ansiedad y ataques de pánico, pero también los trastornos

de pánico con componentes claustrofóbicos, son difíciles de conciliar con la necesidad de una máscara, porque incluso pequeños aumentos de CO 2 pueden provocar e intensificar los ataques de pánico [ 44 , 77 , 78 , 79 ]. Según un estudio psiquiátrico, los pacientes con demencia moderada a grave no comprenden las medidas de protección del COVID-19 y se les debe persuadir para que usen máscaras constantemente [ 80 ]. Según un estudio comparativo, los pacientes con esquizofrenia tienen una menor aceptación del uso de mascarillas (54,9% de acuerdo) que los pacientes de práctica habitual (61,6%) [ 81 ]. Aún no se ha investigado en detalle hasta qué punto el uso de mascarillas puede provocar una exacerbación de los síntomas de la esquizofrenia. Al usar máscaras, se produjo confusión, problemas de pensamiento, desorientación (registro estandarizado mediante calificación especial y escalas Likert, p <0.05) y en algunos casos una disminución en la velocidad máxima y el tiempo de reacción (medidos con el transductor de posición lineal, p <0.05). observado [ 19 , 32 , 36 , 38 , 39 , 40 , 41 ]. Los psicofármacos reducen las funciones psicomotoras en pacientes psiquiátricos. Esto puede volverse clínicamente relevante, especialmente con respecto a la capacidad de reacción aún más reducida y la susceptibilidad aumentada adicional a accidentes de tales pacientes cuando usan máscaras. Para evitar una anestesia provocada por CO 2 no intencional [ 39 ], los pacientes fijos y sedados médicamente, sin la posibilidad de una monitorización continua, no deben ser enmascarados según los criterios de los Centros para el Control y la Prevención de Enfermedades de EE.UU. (CDC). Esto se debe a la posible retención de CO 2 descrita anteriormente, ya que existe el riesgo de pérdida del conocimiento, aspiración y asfixia [ 16 , 17 , 20 , 38 , 82 , 83 ]. 3.6. Efectos secundarios y peligros ginecológicos Como variable crítica, un nivel bajo de dióxido de carbono en sangre en mujeres embarazadas se mantiene mediante un aumento del volumen minuto respiratorio, estimulado por la progesterona [ 22 ]. Para una mujer embarazada y su feto, existe una necesidad metabólica de un gradiente de dióxido de carbono (CO 2 ) fetal-materno . El nivel de dióxido de carbono en sangre de la madre debe ser siempre más bajo que el del feto para asegurar la difusión de CO 2 de la sangre fetal a la circulación materna a través de la placenta. Por lo tanto, los fenómenos relacionados con la máscara descritos anteriormente ( Sección 3.1 y Sección 3.2 ), como los cambios medibles en la fisiología respiratoria con aumento de la resistencia respiratoria, aumento del volumen del espacio muerto ( Figura 3 ) y la retención de dióxido de carbono (CO 2 ) exhalado, son de gran importancia. importancia. Si el CO 2 se vuelve a respirar cada vez más bajo las mascarillas, esta manifestación podría, incluso con aumentos subliminales de dióxido de carbono, actuar como una variable perturbadora del gradiente de CO 2 fetal-materno aumentando con el tiempo de exposición y, por lo tanto, desarrollar relevancia clínica, también con respecto a una reserva de compensación reducida de las mujeres embarazadas [ 20 , 22 , 28]. En un estudio comparativo, 22 mujeres embarazadas que usaban mascarillas N95 durante 20 min de ejercicio mostraron valores de CO 2 percutáneo significativamente más altos, con valores promedio de PtcCO 2 de 33,3 mmHg en comparación con 31,3 mmHg que en 22 mujeres embarazadas sin mascarillas ( p = 0,04) [ 22 ]. La sensación de calor de las mujeres embarazadas también aumentó significativamente con las máscaras, con p <0,001 [ 22 ]. En consecuencia, en otro estudio de intervención, los investigadores demostraron que respirar a través de una máscara N95 (equivalente a FFP2) impedía el intercambio de gases en 20 mujeres embarazadas en reposo y durante el ejercicio, lo que provocaba un estrés adicional en su sistema metabólico [ 28 ]. Por lo tanto, bajo una máscara N95, 20 mujeres embarazadas mostraron una disminución en la capacidad de absorción de oxígeno VO 2 de