When are face masks good for your health, and when are they useless?

Noted cardiologist, professor and Lifestyle columnist doctor Rafael Castillo said that the basic principle is that face masks must prevent transmission of the coronavirus from one who has the virus but may not realize it because he/she is asymptomatic.

“Face masks protect healthy people from inhaling the virus from an infected person. So every time one will be inevitably within three feet (or 1 m) of other people, it’s best to wear them,” he said.

But what if you’re jogging or exercising outside? Is it safe to still wear a mask, or are we unknowingly putting ourselves at risk because of the labored breathing?

“If we’re wearing tight-fitting masks preventing an effective exchange of air, we might experience light-headedness, especially if we’re engaging in some activities that increase our oxygen requirement. When we’re not close to anyone, we may take it off for a few minutes,” Castillo said.

When we engage in moderate to strenuous physical activity like exercise, the body requires more oxygen from the ambient air, and we produce carbon dioxide, which is the waste product of cellular respiration or metabolism, he added.

“So if we don’t remove our face mask while engaging in moderate to strenuous exercise, we may not breathe in enough oxygen, and as a double whammy, we rebreathe the carbon dioxide which our body was trying to get rid of.”

In the article “How does running with a mask impact your performance?” posted by Runner’s World last month, it said that a mask is necessary if you’re running in a populated area where you’re likely to encounter other people. Wearing a face covering, however, is not enough. “One still needs to keep at least six feet of distance between yourself and others while running.”

Castillo explained that when we’re running, our blood delivers oxygenated air to cells and picks up carbon dioxide from the cells. “We release the carbon dioxide as we exhale. We sweat during exercise and soak our face masks, which makes them less porous and prevents the necessary exchange in gases (oxygen and carbon dioxide).”

Castillo pointed out that N95 masks are not prescribed for everyone, only for healthcare workers with a high risk of exposure. “For reusable masks, we now have a lot of good-quality cloth masks we can wash and reuse.”

So for runners and anyone who’s missed the great outdoors, look before you lift . . . those face masks. And be sure to properly replace them so they cover your nose and mouth. —Raoul J. Chee Kee