WWe’ve said it before and we’ll say it again: sleep is paramount in the quest for well-being. While exercising can help you live longer, accumulated poor-quality sleep can have a seriously detrimental effect on your mental and physical state. With that being said, do you know what the cornerstone of poor sleep quality is? It’s not lack of dreams. Rather, the overall quality of your sleep is largely determined by how much deep sleep you get. To find out how much deep sleep you need, we chatted with some of the industry’s leading sleep experts to dig deeper. Later, learn what deep sleep is, how it benefits your health, and why it should be your number one priority moving forward.
What is deep sleep?
To understand deep sleep, you must first recognize the phases of the sleep cycle, as well as the stages of sleep. According to Sleepless in NOLA sleep consultant Nilong Vyas, MD, a medical review expert for the Sleep Foundation, the sleep cycle consists of two phases: REM (rapid eye movement) and NREM (non-rapid eye movement). “NREM sleep is further divided into three stages of sleep,” he explains. The three stages of sleep are N1 (light sleep), N2 (medium sleep), and N3 (deep sleep). “The human body goes through cycles of four to five sleep stages every 90 minutes during the night,” says Dr. Vyas. “N1 is the lightest sleep, N2 is the deepest and plays the most important role in memory consolidation, and N3 is the deepest in NREM sleep.”
Why is deep sleep so important?
While each stage of sleep plays a role in overall health and well-being, deep sleep is the most important because it is responsible for strengthening the immune system, repairing tissue, and releasing growth hormone. All things considered, that’s when the body heals itself, says Dr. Vyas.
So maybe you’ve been feeling down and can’t seem to muster any energy; deep sleep will help; maybe you had a super long day that started with an amazing workout and you felt utterly exhausted by the end; deep sleep will help; maybe you are going through a breakup or other stressful life event; deep sleep will help you.
But here’s the thing: Not only does it have an immediate impact on a person’s well-being, but it’s cumulative, meaning it can offer benefits that last a lifetime, or at the very least. extend your life
“During deep sleep, the brain’s ‘waste management system’ goes in and removes certain proteins that, if not removed, are thought to lead to Alzheimer’s disease and cognitive decline,” says sleep expert and clinical psychologist Michael Breus, PhD, also known as The Sleep Doctor.
Which is better: REM or deep sleep?
Although REM sleep is a different phase of the sleep cycle, it is considered the fourth and final stage of the sleep cycle. Since rapid eye movement is tied to sleep, many people mistakenly assume that it must be a very deep form of sleep in which the subconscious has the uninterrupted ability to fly. Actually, Dr. Vyas says that REM sleep is actually considered less restful.
However, that doesn’t mean REM sleep isn’t important. “REM and deep sleep are completely different, and both are needed for different reasons,” says Dr. Breus. “As an example, during REM sleep is when you move information from your short-term memory to your long-term memory, and when you process emotions; deep sleep is needed for more physical areas.” However, it also plays a role in long-term memory.
How much deep sleep do you need each night?
TL;DR: It depends. The amount of sleep you need depends on your age, gender, medical condition, fitness level, and environment, says Dr. Breus. “As a general guideline, we recommend seven to nine hours of good-quality sleep, but this can vary widely,” he adds. (Not sure where you stand? Check out our story on sleep calculators.)
If you’re over 65, Abhinav Singh, MD, FAASM, medical director of the Indiana Sleep Center and a medical review expert for the Sleep Foundation, says that usually seven to eight hours will suffice.
No matter your age, if we break it down by stage, Dr. Singh says that 20 to 25 percent of your total sleep should be deep sleep, while another 20 to 25 percent should be REM.
What happens if you don’t get enough sleep?
Considering the vital role it plays in our overall well-being, Dr. Breus reveals that not getting enough sleep is officially considered sleep deprivation. “Sleep deprivation affects every organ system and every disease state, literally all you do, you do better with a good night’s sleep,” he says.
More specifically, Dr. Breus notes that a lack of sound sleep can lead to marked physical and cognitive impairment, including slower reaction time, lower testosterone levels, memory problems, riskier decisions, trouble concentrating, and further. And then there’s the emotional impact of sleep deprivation. When you don’t get enough, you will become more anxious and may experience deeper depression. Together, all of these side effects make one thing abundantly clear: deep sleep should be your priority, each and every night.
When does deep sleep occur?
While a complete sleep cycle lasts about 90 minutes and is made up of the four stages of sleep (N1, N2, deep sleep, and REM sleep), the amount of time you spend in each stage changes throughout the night. According to The Sleep Foundation, you typically sleep the deepest during the first half of the night. Then, in subsequent sleep cycles, you spend less time in N1, N2, and N3 stages, and more time in REM sleep.
What happens if you wake up during deep sleep?
Since stage N3 is the deepest stage of sleep, it makes sense that it would be the hardest to overcome. According to Dr. Breus, the deep sleep stage is the hardest to wake up. If someone wakes up during this stage, he says it’s not uncommon to feel especially groggy. “This experience is what is known as sleep inertia,” he reveals on his website. He likens it to Isaac Newton’s Law of Inertia and points out that unless a pressure force is at play to entice someone to wake up, it’s totally normal to want to stay asleep, or even go back to sleep in the process. This is a sign that you are in a deep sleep stage and you need it to feel rested.
However, if you continually wake up each morning wishing you could get some more sleep, it might be time to reassess your sleep routine and hygiene, as certain habits can make falling asleep and staying asleep much easier. For example, eating a snack that contains foods that help you sleep, taking over-the-counter sleep aids (such as Olly Sleep Gummies, $13), wearing breathable cotton pajamas (such as Printfresh Bagheera Sleep Shirt, $118), sleeping on soft, moisture-wicking sheets humidity (like the Purple SoftStretch Sheet Set, $189), and waking up to an alarm clock at dawn (like the Hatch Restore 2, $200) can make a world of difference in the quality of your sleep.
If after adjusting your sleep routine you still find falling asleep and staying asleep challenging, or if you experience poor sleep quality in general, you may want to see a doctor to discuss prescription sleeping pills. and the best steps to take in general.
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