Light sleep is the beginning of your sleep cycle and your body's way of winding down. Breathing, heart rate and muscle changes prepare your body for the deeper sleep to come. Light sleep is broken ...

If you’ve ever wondered whether deep sleep or REM sleep is “more important,” think of it like comparing cardio to weight training. Both are essential. Both overlap in benefits when done intensely.

(CNN) — Need another reason to prioritize your sleep? Not spending enough time in the two deep stages of sleep — slow-wave and rapid eye movement, or REM, sleep — may hasten the deterioration of parts ...

Need another reason to prioritize your sleep? Not spending enough time in the two deep stages of sleep — slow-wave and rapid eye movement, or REM, sleep — may hasten the deterioration of parts of the ...

We talked to sleep doctors about the tell-tale signs of not getting enough deep sleep and what to do about it. What is deep sleep? There are two primary sleep phases: rapid eye movement (REM) and ...

ATLANTA — Need another reason to prioritize your sleep? Not spending enough time in the two deep stages of sleep — slow-wave and rapid eye movement, or REM, sleep — may hasten the deterioration of ...

Sign up for CNN’s Sleep, But Better newsletter series. Our seven-part guide has helpful hints to achieve better sleep. Need another reason to prioritize your sleep ...