Stress hormones in the blood have a big influence on the brain's circadian rhythm, according to research in rats.

Our biological clock helps guide our immune system's response to invaders like viruses and cancer, new research with mice indicates.

A new intervention helps teens get more sleep every night. The secret? Earlier bed times and bright flashes of light just before waking.

The right timing and the right temperature makes a bath before bedtime a great way to fall asleep faster and get better sleep.

"What is completely fascinating is that this process evolved in some animals, like hamsters and voles, and not in others, like sheep or humans."

The benefits of morning exercise and evening workouts differ, research in mice shows. But that doesn't necessarily mean one is better.

A siesta might be wise in hot weather, but a newly discovered fruit fly gene called "daywake" prevents naps in cool weather.

Past research has linked shift work and preterm birth. New research on daily schedules in the first trimester clarifies that connection.

Data from Spotify users in 51 countries offer researchers a new way to evaluate how people are feeling—and how they use music to manage their emotions.

"...the time at which teens generally fall asleep is biologically determined—but the time at which they wake up is socially determined."