As we sleep, our brain moves through four stages and two phases: non-rapid eye movement (NREM) and rapid eye movement (REM). The brain has four stages within the NREM phase. Each stage and phase of ...

Stages of sleep explained in clear terms, showing how sleep unfolds through the night and why order, timing, and consistency ...

Two particular phases in your nightly routine seem to play outsize roles in cognitive health. By Mohana Ravindranath A good night’s sleep isn’t just about the number of hours you log. Getting quality ...

Learn facts about sleep, during which the body rests, recuperates and performs essential repairs. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works.

The internet claims waking at the end of a sleep cycle will leave you refreshed, but experts aren’t convinced. By Clarissa Brincat Published Sep 9, 2025 9:00 AM EDT Image: DepositPhotos Get the ...

Sleeping for 7 to 9 hours at night isn't the only way to catch some z's. Here are four alternative sleep cycles -- and they're pretty obscure. Annie Miller Medical Reviewer Annie Miller is a licensed ...

Advanced sleep phase disorder is a rare condition that causes your natural circadian rhythm, or sleep-wake cycle, to occur earlier than typical. As humans, our sleep-wake cycle— also known as our ...

Beth Ann Malow receives funding from the American Academy of Sleep Medicine and previously received funding from Autism Speaks, National Institutes of Health, Department of Defense, and the Patient ...