3 weeks of bed rest was worse for the body's ability to do physical work than 30 years of aging.

Out of hundreds, if not thousands, of collegiate athletes who had COVID and went through brief quarantine, how many do you think had symptoms that lasted more than 12 weeks? ... 0.06%. 2 people out of 1600.

We found that the heart loses about 1% of its muscle mass a week in bed ... When we monitor people for 12 weeks, the heart just got smaller and smaller and smaller. Now, obviously, it can't get continue to atrophy forever .... How low can you go? And it's about 25%.

The optimal dose, if you will, of physical activity is four to five days a week over a lifetime.