We all know that exercise is good for us, but why, exactly? What does exercise really do for us, for our bodies, for our minds, for our social lives? Physicians at The Methodist Hospital in Houston propose their Top 10 list of reasons to exercise this holiday season.

1. Exercise helps keep your arteries flexible and malleable, which prevents heart disease and heart attacks.

WASHINGTON, Dec. 20 - Despite promising discoveries and multibillion-dollar investments, cancer research is quietly undergoing a crisis. Federal drug regulators will soon announce several initiatives that they hope will help salvage the field.