Dr. Jeffrey Sankoff

With the recent blood shortage, and donors flocking to help, how does blood donation affect athletic performance? An ER doc explains how to time your blood donation for minimal impact on training and racing.

And it's not just because of the physiological responses inside your body. Dehydration gets inside your head.

"This is not a mild disease."

And what we don't know yet.

Exercise has a hugely beneficial impact on cardiovascular health and mortality rates, but at a certain volume of exercise those benefits start to decrease.