“I’ll sleep when I’m dead.” Have you ever heard that phrase uttered in a movie or by a friend with a fast lifestyle? Maybe you’ve even said it yourself? Deep sleep is for wimps, a waste of time—that’s the opinion of many people.

Well, anyone who truly believes may go to sleep sooner than they think—without sleep, death is certain. In fact, the longest anyone has been able to voluntarily stay awake is 11 days, when a 17-year-old student managed to do so for a high-school science project in 1965. By day 11, he was practically a vegetable before finally going to sleep

While research hasn’t definitively found the maximum amount of time a human can stay awake without dying, a 1999 study on rats found that going two weeks without sleep is fatal. Sleep is critical for all mammals; if it weren’t, why would anyone ever close their eyes and take their brain offline for hours at a time? Especially animals that are subject to predators. There must be something very important about sleep.

And it’s more than just taking a catnap after a heavy lunch or catching a few zzz’s after a night of cramming for a presentation. To truly make every day productive, your body needs deep sleep.

Deep sleep means that your body completes four to five stages of sleep every night:

  • Stage 1 is when you are just drifting off to sleep. It is the lightest stage of sleep, also known as alpha sleep. In Stage 1, a person can be awakened fairly easily.
  • Stage 2 is the next deeper stage of sleep. In Stage 2, eye movements and brain waves begin to slow down.
  • Stage 3 is when brain waves slow to what are known as “delta waves” and it becomes harder to wake up. In Stage 3, you may sleep through noises, but if you are wakened, you’ll likely be groggy.
  • Stage 4 is the often referred to as the deepest level of sleep, also known as rapid eye movement or REM sleep. If you’ve ever seen someone’s eyelids moving while they slept, it’s likely because they were in REM. But while the eyes dart around under the eyelids in REM, the rest of the muscles of the body are essentially paralyzed.

Dreams mostly occur in REM sleep. If you’re wakened during REM or at the end of a REM cycle, you might be able to remember dreams in vivid detail.

It takes about an hour-and-a-half to go from Stage 1 through Stage 4 (one sleep cycle), and then another cycle begins. The average adult should go through about four or five cycles a night.

When someone is suffering from sleep apnea, however, the sleep cycles are repeatedly disrupted, usually during Stage 3, meaning the REM stage may not happen at all. Sleep apnea is a disorder in which a person experiences very shallow breathing or repeated stops in their breathing during sleep. Sometimes, that happens hundreds of times a night. This will result in a disruption in their sleep.

Sleep apnea occurs in Stage 3 of the sleep cycle, just before a person is ready to enter Stage 4, or REM. Since REM is the deepest stage of sleep, and is when the body’s cells regenerate, then disrupted REM can leave you feeling unrested. No matter  how much time you spend in bed, without entering REM sleep, you won’t have the energy to function well during the day. Over time, sleep apnea can cause even greater problems than being tired, irritable, lethargic, and depressed—it can lead to chronic, even deadly diseases. It is important to know without REM sleep, the brain does not clean itself from all the toxins accumulated during awake time. This may be a causative factor in Alzheimer’s.

Maybe you know someone that snores, stops breathing, and then jerks awake during sleep? That’s not normal—it’s a sign of a sleep-disordered breathing problem. But there are treatments to end those sleep disruptions. Visit for more information. We’re here to help you get a good night’s sleep.