"The study shows that our biologically hardwired seasonal timing affects how we adjust to changes in our daily schedules."

A one-hour adjustment to the clock on the wall may not sound dramatic. But our biological clock begs to differ.

An expert digs into how our circadian system works, its far-reaching influence on health, and how to keep it running smoothly.

New research finds connections between mood and circadian rhythm disruptions in a study using Fitbit data from hundreds of medical interns.

Brain cancer has an internal clock and syncs its daily rhythms to match—and take advantage of—the rhythms of its host.

Recent findings could pave the way for new approaches to treating disorders related to our body clock, researchers report.

"Our findings demonstrate the pivotal role of the circadian clock in enhancing immune checkpoint inhibitor therapy."

A new study finds mood cycles hit their lowest point around 5 in the morning and their highest around 5 in the evening.

"Teens are chronically sleep deprived," says Alison Kole. "And we need to start talking about why that is."

Grizzly bears' circadian rhythm keeps on ticking, even when they are in hibernation, a new study shows.