Circadian Rhythm

Your body keeps time. Circadian rhythms—roughly 24-hour cycles that coordinate sleep, hormones, metabolism, and mood—are set primarily by light and fine-tuned by behaviors like...

When your lifestyle runs on one clock and your biology runs on another, fatigue, fogginess, and cranky mornings become the norm. This chronic mismatch...

Your sleep-wake cycle is the daily rhythm that helps you feel alert by day and sleepy at night. Training it means using timed “zeitgebers”...

Circadian rhythm disorders are conditions where your internal 24-hour body clock falls out of sync with your social or work schedule, leading to trouble...

Chronotypes are your built-in timing preferences—being a “morning lark,” “night owl,” or somewhere between—driven by your circadian clock and shaped by genetics, age, and...

When your body clock doesn’t match the clock on the wall, performance, mood, and health suffer. Whether you’re crossing time zones or clocking into...

If you’ve ever wondered why your baby naps in fragments while your school-age child seems wired at 9 p.m., you’re bumping into biology: children’s...

Your sleep schedule isn’t just about willpower or coffee—it’s anchored by circadian genes, the DNA instructions that build your internal 24-hour clock. These genes...

Circadian rhythms are the body’s 24-hour programs for sleep, alertness, body temperature, hormone secretion, and metabolism. They’re coordinated by a master clock in the...

Light is the master time cue for your body’s internal 24-hour rhythm. In simple terms, light resets your circadian clock by signaling special retinal...