MASK -EXERCISING- MAST : RESEARCH

Wearing a mask during exercise reduces the risk that we infect someone with the novel coronavirus if we unwittingly carry the disease.

But wearing a mask also affects how the exercise affects us, according to scientists who have begun to look into the effects of covering your face while working out.

Their research and insights, some of them based on self-experimentation, raise practical questions about whether some types of masks maybe better than others for exercise, how often masks should be changed during prolonged exercise and how much we should expect our heart rates to soar if we attempt to interval-train while wearing a mask.

If you wear a mask before running or cycling at your usual pace, your heart rate will be more elevated than before. ''You should anticipate that it will be about eight to 10 beats higher per minute'' when you wear a mask than when you do not,'' Dr. Bryant said.

This exaggerated rise in heart rate will be most pronounced during intense efforts, he said, such as hill repeats or intervals.

Some people also could experience lightheadedness during familiar workouts while masked, said Len Kravitz, a professor of exercise science at the University of New Mexico.

He is in the early stages of planning a a large study of masks and exercise with funding from A.C.E. that will begin when pandemic restrictions allow, he said.

But he has already conducted an informal experiment with two students, both experienced athletes. One ran, masked, without breathing difficulties, he said. the other wearing the same type of cloth mask, felt dizzy after a few minutes of exertion.

Thankful, such discomforts can most likely be minimized by judicious mask choice and fitting., said Christa Janse van Rensburg, a professor of exercise science at the University of Pretoria in South Africa, who wrote the commentary about masks with her graduate student, Jessica Hamuy Blanco.

Avoid paper surgical masks altogether during the exercise, she said, since they rapidly become wet when we breathe into them vigorously and lose some of their ability to block exiting germs.

Cotton cloth masks likewise dampen easily. Cloth masks made from breathable, synthetic materials should lessen moisture buildup. Choose, models, though, that ''have two layers of fabric or less,'' she said, to avoid facial overheating and any bunching of the cloth that might constrict breathing.

Some exercisers may prefer neck gaiters, which can be pulled over the mouth and nose but remain open at the bottom, increasing air flow. ''This can be good from a comfort point of view,'' Dr. Jansevan Rensburg said, ''but perhaps with the trade-off of less-effective infection control.'' Look for gaiters in summer weight fabrics.

Plan, too, to carry extras of your preferred mask if you will be exercising for more than about 30 minutes, Dr. Bryant said. Even breathable fabrics become drenched at that point and should be replaced.

Try bot to touch the front of the used mask, since any viral particles you came into contact with could have accumulated there, he said, and after removal, pack or dispose of it carefully.

Some athletic clothing companies, including Under Armour, Koral and Zensah, have begun to make masks for use during exercise.

But do not be deterred in the interim from wearing a mask if you will be exercising around other people., Dr. Bryant said. Wearing a mask can be particularly important if you are exercising indoors at a gym, where air circulation is less likely to dissipate the virus.

''I know some people find them unpleasant'' while running or cycling ''and there are controversies'' about whether they should be mandatory, Dr. Bryant said.

''But I look on masks as an opportunity to be a good citizen and show that you care about the well being of others,'' he said, even as you bolster your own well-being with a workout.

The Honor and Serving of the latest Global Operational research on Masks and Daily Routines, continues. The World Students Society thanks author Gretchen Reynolds.