As discussed in another Savoir-Sport sheet (S894: http://www.insquebec.org/formation/savoir-sport/?requestedFiche=S894), as soon as the use of an antiviral protective mask is recommended or becomes mandatory in order to reduce the risk of infection, you might wonder what the physiological impacts are during exercise, for example during periods of high-intensity physical exercise. The body adapts to the airflow being limited when wearing the face mask mainly through compensatory stimulation of certain elements (e.g. respiratory rate). But, during prolonged or repeated maximal-exertion activities, respiratory function is already under heavy stress, which could limit the compensatory effects.

Up until of June 2020, no research team had measured the effect of wearing a mask at maximal intensities (close to VO2max). But in July 2020, Fikenzer et al. attempted to fill this gap by assessing the cardiopulmonary function of healthy individuals wearing surgical masks or FFP2/N95 masks during an incremental test to exhaustion.

It showed that at maximal intensity, ventilation and performance are reduced by a surgical mask ( 8.8% and 4.5%, respectively) and are significantly affected by the FFP2/N95 mask ( 12.6% and 13.1%, respectively). The same is true for general discomfort, which is increased by 2.4 points out of 10 with the surgical mask and by 4.2 points with the FFP2/N95 mask. These results are therefore particularly interesting, because they show that when respiration is concerned, it is not possible to fully compensate for the airflow limitation if the intensity is high.

It remains to be seen whether the same conclusions could be reached with athletes. In addition, the Fikenzer et al. study does not account for changes in cardiopulmonary function at each stage of the test, for example in regard to O2 saturation (but many physiologists argue that an appropriate facial covering will not affect blood oxygenation more than the exercise itself). This study also does not indicate whether there are health risks associated with high-intensity exercise when wearing a mask.

In short, during high-intensity aerobic activities with a mask, a healthy subject does not fully compensate for the airflow restriction, resulting in reduced performance at maximal aerobic intensity, and it is not known whether this type of limitation presents health risks.

It should be noted that to be “appropriate”, a face covering or face mask must be permeable to gases while restricting the passage of droplets. The challenge is to find or design face masks and coverings that are as comfortable as possible.

More research will also be needed to: 1) determine the percentage of maximal aerobic power at which the body is no longer able to compensate; 2) verify whether the inability to compensate is associated with health risks; and 3) find out how the impact of wearing a mask varies according to the level of performance of the subjects.