How important is light for sleep-wake cycles?

Your brain's "master clock" is sensitive to light, explains Michael Timothy Smith, MA, PhD, director of the Behavioral Sleep Medicine Program at Johns Hopkins University. He discusses how that clock affects your sleep.

The relationship between sleep and heart health may be a two-way street. Here’s what you need to know to improve both.

Constant caffeine, skipped workouts and other perils of the late-night worker.

Too much screen time can harm sleep, mood, and much more.

Are you wondering if this popular supplement is a safe way to get more sleep? Get the facts.

Learn how sleep loss factors into higher anxiety and depression rates—and what to do about it.