The study below was reported in the International Journal of Environmental Research and Public Health (Publication date April 20, 2021) and details the harm caused by mask wearing and adds to a growing body of under-reported, censored and suppressed public health information that contradicts the biomedical narrative that masks are safe and effective and recommended by the CDC.
65 German Studies: Face Masks Cause Mask-Induced Exhaustion Syndrome (MIES)
Int. J. Environ. Res. Public Health 2021, 18(8), 4344; https://doi.org/10.3390/ijerph18084344 , April 20, 2021
See: Face Masks (Lack of Safety and Ineffectiveness Research)
Mask Induced Exhaustion Syndrome (MIES)
Here are the pathophysiological changes and subjective complaints:
1. Increase in blood carbon dioxide
2. Increase in breathing resistance
3. Decrease in blood oxygen saturation
4. Increase in heart rate
5. Decrease in cardiopulmonary capacity
6. Feeling of exhaustion
7. Increase in respiratory rate
8. Difficulty breathing and shortness of breath
11. Feeling of dampness and heat
12. Drowsiness (qualitative neurological deficits)
13. Decrease in empathy perception
14. Impaired skin barrier function with acne, itching and skin lesions
Results from Mask Wearer Studies
This first-of-its-kind literature review on the adverse effects of face masks, titled “Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards?,” reveals there are clear, scientifically demonstrable adverse effects for mask wearers, both on psychological, social and physical levels.
For complete abstract download this.
Many countries introduced the requirement to wear masks in public spaces for containing SARS-CoV-2 making it commonplace in 2020. Up until now, there has been no comprehensive investigation as to the adverse health effects masks can cause. The aim was to find, test, evaluate and compile scientifically proven related side effects of wearing masks. For a quantitative evaluation, 44 mostly experimental studies were referenced, and for a substantive evaluation, 65 publications were found.
The literature revealed relevant adverse effects of masks in numerous disciplines. In this paper, we refer to the psychological and physical deterioration as well as multiple symptoms described because of their consistent, recurrent and uniform presentation from different disciplines as a Mask-Induced Exhaustion Syndrome (MIES). We objectified evaluation evidenced changes in respiratory physiology of mask wearers with significant correlation of O2 drop and fatigue (p < 0.05), a clustered co-occurrence of respiratory impairment and O2 drop (67%), N95 mask and CO2 rise (82%), N95 mask and O2 drop (72%), N95 mask and headache (60%), respiratory impairment and temperature rise (88%), but also temperature rise and moisture (100%) under the masks. Extended mask-wearing by the general population could lead to relevant effects and consequences in many medical fields.
1. Masks in everyday use risk self-contamination by the wearer both inside and outside, including via contaminated hands [5,16,88]. 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.
2. Serious infection-causing bacteria and fungi should be mentioned here [86,88,89], but also viruses .
3. Masks worn 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 .
4. History shows that influenza pandemics of 1918-1919, 1957-58, 1968, 2002, in SARS 2004-2005 and 2009, masks DID NOT fight against viral infections [67,144].
5. 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 .
6. The mask is nothing more than a symbol of the wearers fear of infection – reinforced by the collective fear mongering, which is constantly nurtured by mainstream media .
7. The mask represents psychological support for the general population as a false sense of security to reduce anxiety. 
8. The WHO’s recommendation of the mask is about giving 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. .
By Kai Kisielinski, Paul Giboni, and et al. Via MDPI