REM stages and one REM stage. Ideally, you repeatedly cycle through each stage. Learn how long each stage lasts.

Oxygen re-saturation during sleep is significantly affected by sleep stage and by cardiovascular and pulmonary comorbidities.

People on TikTok and other social media say they feel more alert when they have had fewer hours of sleep—but sleep scientists warn this is a false sense of energy ...

In nonrapid eye movement (NREM), a state of cardiovascular relaxation ... ocular movements is concentrated in rapid eye movement (REM) sleep. During this phase, fluctuations in arterial pressure ...

Scientists have long noted eerie parallels between psychedelic trips and rapid eye movement (REM) sleep, the stage during which you dream. Some even suggest psychedelics could induce a “waking ...

What if we didn't need sleep to dream? Well, scientists may have found a way to hack those benefits even when you're awake.

If you're on the fence about the best sleep masks, know that there are two types of sleepers in this world: Those who can ...

Sleep deficiency is associated with atrophy of the inferior parietal region of the brain, according to a study published online March 31 in the Journal of Clini ...