The effects of wearing facemasks on oxygenation and ventilation at rest and during physical activity.

BACKGROUND: Facemasks are recommended to reduce the spread of SARS-CoV-2, but concern about inadequate gas exchange is an often cited reason for non-compliance. RESEARCH QUESTION: Among adult volunteers, do either cloth masks or surgical masks impair oxygenation or ventilation either at rest or during physical activity? STUDY DESIGN AND METHODS: With IRB approval and informed consent, we measured heart rate (HR), transcutaneous carbon dioxide (CO2) tension and oxygen levels (SpO2) at the conclusion of six 10-minute phases: sitting quietly and walking briskly without a mask, sitting quietly and walking briskly while wearing a cloth mask, and sitting quietly and walking briskly while wearing a surgical mask. Brisk walking required at least a 10bpm increase in heart rate. Occurrences of hypoxemia (decrease in SpO2 of ≥3% from baseline to a value of ≤94%) and hypercarbia (increase in CO2 tension of ≥5 mmHg from baseline to a value of ≥46 mmHg) in individual subjects were collected. Wilcoxon signed-rank was used for pairwise comparisons among values for the whole cohort (e.g. walking without a mask versus walking with a cloth mask). RESULTS: Among 50 adult volunteers (median age 33 years; 32% with a co-morbidity), there were no episodes of hypoxemia or hypercarbia (0%; 95% confidence interval 0-1.9%). In paired comparisons, there were no statistically significant differences in either CO2 or SpO2 between baseline measurements without a mask and those while wearing either kind of mask mask, both at rest and after walking briskly for ten minutes. INTERPRETATION: The risk of pathologic gas exchange impairment with cloth masks and surgical masks is near-zero in the general adult population.

Temporal dynamics of resting EEG networks are associated with prosociality.

As prosociality is key to facing many of our societies' global challenges (such as fighting a global pandemic), we need to better understand why some individuals are more prosocial than others. The present study takes a neural trait approach, examining whether the temporal dynamics of resting EEG networks are associated with inter-individual differences in prosociality. In two experimental sessions, we collected 55 healthy males' resting EEG, their self-reported prosocial concern and values, and their incentivized prosocial behavior across different reward domains (money, time) and social contexts (collective, individual). By means of EEG microstate analysis we identified the temporal coverage of four canonical resting networks (microstates A, B, C, and D) and their mutual communication in order to examine their association with an aggregated index of prosociality. Participants with a higher coverage of microstate A and more transitions from microstate C to A were more prosocial. Our study demonstrates that temporal dynamics of intrinsic brain networks can be linked to complex social behavior. On the basis of previous findings on links of microstate A with sensory processing, our findings suggest that participants with a tendency to engage in bottom-up processing during rest behave more prosocially than others.

The Physiological Impact of Masking Is Insignificant and Should Not Preclude Routine Use During Daily Activities, Exercise, and Rehabilitation.

PURPOSE: Masking has been employed as a strategy for reducing transmission of a variety of communicable diseases. With the outbreak of SARS-CoV-2, many countries have implemented mandatory public masking. However, the perceived impact of mask use on pulmonary function has been a deterrent to public compliance with recommendations. COVID-19 has shed light on the impact that comorbid cardiac and pulmonary conditions may have on disease severity. This knowledge has led to increased primary and secondary prevention efforts for which exercise and rehabilitation are central. The importance of safe methods of exercise while mitigating risk of viral transmission is paramount to global recovery from the pandemic and prevention of future outbreaks. METHODS: We constructed a focused literature review of the impact of various masks on pulmonary function at rest and with exercise. This was then incorporated into recommendations for the integration of masks with exercise and rehabilitation in the COVID-19 era. RESULTS: While there is a paucity of evidence, we identified the physiological effects of masking at rest and during exercise to be negligible. The perceived impact appears to be far greater than the measured impact, and increased frequency of mask use leads to a physiological and psychological adaptive response. CONCLUSIONS: Masking during daily activities, exercise, and rehabilitation is safe in both healthy individuals and those with underlying cardiopulmonary disease. Rehabilitation participants should be reassured that the benefits of masking during COVID-19 far outweigh the risks, and increased frequency of mask use invokes adaptive responses that make long-term masking tolerable.