However, understanding your sleep stages and cycles is extremely important, as it can give you an in depth insight into how ...

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. Lara Vukelich Lara Vukelich is a freelance writer in ...

Officially called the slow-wave sleep cycle, this is the third stage of a human 90-minute sleep cycle, lasting around 20 to 40 minutes. It's said to be the most restful stage, where brain waves ...

It is difficult to wake someone in Stage 4 of a sleep cycle, which is why you might feel more groggy if you wake up during this stage. The fifth stage, REM sleep, is when most dreaming occurs.

Slow-wave sleep is the third stage of a human 90-minute sleep cycle, lasting about 20–40 minutes. It's the most restful stage ...

Slow-wave sleep is the third stage of a human 90-minute sleep cycle, lasting about 20–40 minutes. It's the most restful stage, where brain waves and heart rate slow and blood pressure drops.