Our natural sleep-wake cycles are determined by our body’s circadian rhythm.

As board-certified sleep specialist Michael J. Breus, Ph.D., explains to mbg, the circadian rhythm is a roughly 24-hour cycle that your body repeats over and over again. “Essentially, it ‘manages’ your sleep, starting and stopping it by sending neurochemical signals that tell each area, organ, or receptor what to produce, what to receive, and what to do,” he explains.

And according to sleep naturopath Katherine Darley, New York State, “each cell also has clock genes that cause the cell to perform more or less of its functions at different times of the day.”

Many of our rhythms are dictated by the suprachiasmatic nucleus (SCN), the body’s “central pacemaker” in the brain’s hypothalamus. Environmental factors such as lighting affect this pacemaker, so you’ll often hear advice to seek bright light during the day and darkness at night to maintain a healthy circadian rhythm.

Synchronizing your body clock with the actual clock and its constant day-night cycles can benefit many aspects of your health, including sleep.