All the scolds nagging about masks should keep this fact in mind:

“People with breathing problems (ironically) are discouraged from wearing a mask without getting a doctor's recommendation. In one statement, CA Dept. of Public Health writes, "Wearing a mask may actually be harmful to some people with heart or lung disease because it can make the lungs work harder to breathe." A doctor will look at the patient's condition, ability to draw in air, and guide them on how to make it fit right if recommended.”