Old School P.E. is a two-hour exercise program strictly for adults, built around grown-up versions of gym class staples. Participants say getting in shape is a bonus to the main attraction ? a Friday night out with friends, away from the kids.

Research is starting to show that some surprisingly simple positive reinforcements ? quick e-mail messages and short phone calls ? can motivate people to get moving.

Sloppy teaching and growing numbers of overly competitive students are giving yoga lovers serious and scary injuries: slipped disks, torn tendons, even strokes.

Can sex impair athletic performance? And are forced repetitions really necessary? Smart Fitness answers your workout questions.

A new study shows a boost in life expectancy for HIV patients since the advent of antiretroviral drug therapy.

Are cell phones safe to use? Are they linked to cancer? Read experts' opinions.

Researchers have tested gummy bears made with a sugar substitute that wards off cavity-causing bacteria.

Wear, tear, and DNA damage can age you. But aging may also be written into your genes, as it is in worms, scientists report.