Add Yahoo as a preferred source to see more of our stories on Google. Person wearing a wearable sleep tracker in bed Light sleep is the beginning of your sleep cycle and your body's way of winding ...

A little-known and poorly understood sleep disorder that occurs during the rapid eye movement, or REM, stage of sleep has ...

REM stands for rapid eye movement — a stage in the sleep cycle when your brain is almost as active as when you’re awake. Getting enough REM sleep is crucial, as it helps you store information and ...

Scientists have recently shown that both the quality and the amount of sleep we get may influence our risk of developing Alzheimer’s disease. Now, a study suggests that people who take significantly ...

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 ...

A growing body of research has made it clear that sleep health has a direct impact on your physical health. Among other things, regularly logging enough high-quality sleep is linked to a lower risk of ...

It can be tough to calculate exactly how long you’re in REM, but many health trackers use your heart rate, heart rate variability, and data on your movements to make solid estimations. (Just know that ...