Healthy subjects wearing masks for Hypoxia

There is some evidence that the use of surgical masks can induce mild hypoxia with a low level of activity (e.g. performing surgery). There is no evidence that this decrease in oxygenation is clinically significant. The degree of hypoxia associated with surgical mask use, N-95 mask use or the combination at rest and with exertion is unclear and warrants further investigation, particularly given the current widespread use of both due to the COVID-19 pandemic. Our working hypothesis is that there is a decrement in oxygenation with the use of any mask that is higher with an N-95 than a surgical mask and higher still when wearing both and that this decrement is more pronounced with exertion than at rest.