A doctor based in Dublin, Ireland, has debunked the idea that a face mask lowers oxygen levels. In fact, he's shown that even wearing several has no effect.

An intensive care unit doctor in England ran about 22 miles in a mask to show people that face coverings won’t hinder their oxygen levels.

JUST DIET, MAKING THE DIFFERENCE, AND SLEEP APNEA HAPPENS WHEN SOMEONE STOPS BREATHING FOR SHORT TIMES AS THEY SLEEP, AND THE ...

A new study about mask wearing during the coronavirus pandemic found that masks don’t cause a person’s oxygen levels to drop.