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

Have you ever considered that how you sleep could actually shorten your life? For most people, the answer is a resounding "no ...

When is the best time to take nap? A sleep doctor reveals the optimal time of day to take a nap in order to feel rested and ...

Lower satisfaction with one's sleep quality has been linked to higher blood pressure, stiffer arteries, coronary heart disease and blood pressure that doesn't decrease during the night.