sleep

A new study finds that too little sleep boosts a signal in the body that may drive a stronger desire to eat. It's the latest evidence linking sleep deprivation to overeating and increased body weight.

Americans aren't getting enough sleep in general. But if you live in Minnesota or South Dakota you have a better chance of getting enough shuteye. And people in Hawaii are most sleep-deprived.

Late-night coffee, tea or cola does more than keep you up, scientists say. The amount of caffeine in a double espresso can delay the internal clock in cells throughout your body by about 40 minutes.

During sleep, the brain locks in existing memories and can even form new ones. Scientists say they are starting to understand how that happens. A midnight snack may interfere.