Diet, exercise and sleep are fundamental to our health, but so it our relationship to light. A massive, new study suggests light-driven disruption can take years off our lives.

Scientists think the timing of exercise might matter for performance — and for your overall health. Here's what to know about their latest findings.

Wondering how to prepare for sleep disruption? Should you take melatonin or other sleep aids? Here's answers from researchers and seasoned travelers — including NPR's international correspondents.

Call it "precision waking" — the alleged ability to decide when you want to wake up and then doing so, without an alarm. If you think you can do it, you're not alone, though how is still mysterious.

We mark our days by sunlight, with special receptors in our eyes that respond to light and help reset our body clocks each day. This man can't see, but is still a circadian wiz. Here's how.

Just a night or two of exposure to faint light is enough to raise your pulse and increase insulin resistance — factors that increase the risk of heart disease and diabetes, researchers find.