Why do I get sleepy?
Like all animals, our bodies follow a 24-hour schedule known as a circadian rhythm, sort of an internal alarm clock that keeps time by tracking light and darkness.
Why do I get sleepy?
Like all animals, our bodies follow a 24-hour schedule known as a circadian rhythm, sort of an internal alarm clock that keeps time by tracking light and darkness. Our brains can detect light even when we’re snoozing (through the thin skin of our eyelids). Sunrise in the morning triggers your circadian rhythm’s “day mode.” Your brain triggers the release of chemicals called hormones that raise our body temperature and make you feel more alert. Sunset switches your body to night mode. Your body temperature starts to fall and your brain triggers the release of a hormone called melatonin that makes you feel sleepy.
Why do we need to sleep, anyway?
Although no one has ever died from a lack of sleep, we all need to hit the hay. (One man perished after staying awake for 11 days, but doctors suspect other factors played a role in his death.)
A good night’s sleep is just as important as a healthy diet. Your waking hours are crammed with activities and tasks that give your noggin a real workout. Researchers have found that all that processing causes chemicals to clutter your brain. While you snooze, your brain goes into housekeeping mode, flushing the toxins, organizing memories, and preparing itself for a busy day of deep thinking.
Sleep clears your head—literally! Your immune system works at peak efficiency when you sleep, too, which is why doctors prescribe rest as the only surefire cure for the common cold.
Text adapted from the Nat Geo Kids book Why Not?, by Chrispin Boyer, yawning boy photograph by picturepartners / Shutterstock