How Much Deep, Light, and REM Sleep Do You Need?

If there’s one thing that we unknowingly sacrifice in our hectic lives, it’s our sleep. We may sacrifice sleep to meet deadlines, enjoy our favorite media, socialize, or engage in other activities, not realizing how important sleep is to our mental, physical, and emotional health. On the other hand, we may want to get quality sleep but have trouble because of stress, medications, a chronic illness, or other issues.

According to the National Institute of Neurological Disorders and Stroke, quality sleep is as essential to survival as food and water since it impacts nearly every tissue and system in the body. The institute says that a lack of quality sleep can increase the risk of chronic health problems, such as obesity, high blood pressure, type 2 diabetes, cardiovascular disease, and depression. It also affects our mood and makes us cranky when we do not get enough sleep.

So, how much sleep is “enough sleep?” The American Academy of Sleep Medicine and Sleep Research Society recommends healthy adults get seven to nine hours of sleep each night, and this applies to people over 60, too. However, older adults tend to sleep less and have difficulty sleeping as they age. Babies and children need more sleep than adults, according to the U.S. Centers for Disease Control and Prevention (CDC). The CDC recommends 13- to 18-year-olds get 8–10 hours of sleep.

The Stages of Sleep

We may not realize it, but we sleep in stages, and each stage has a purpose. Within these stages are cycles that last between 90 and 120 minutes. What’s more, a typical night’s sleep cycles through three stages of non-rapid Eye Movement (NREM) sleep and one stage of Rapid Eye Movement (REM).

The first part of our sleep begins with NREM, which is divided into three stages:

Light sleep: NREM Stage 1

In light sleep, your eyes are closed, and you’re falling asleep, but it’s easy to wake you up. The transition between being awake and asleep can last for up to 10 minutes. This stage accounts for five percent of total sleep time.

Deeper Sleep: NREM Stage 2

You’re still in light sleep, but it’s deeper than NREM Stage 1 sleep. In NREM Stage 2, your body is preparing to go into deep sleep. Your breathing and heart rate decrease, your body temperature drops, and you may even start grinding your teeth. This can last between 10-25 minutes. NREM Stage 2 accounts for 45 percent of total sleep time.

Deepest Sleep: NREM Stage 3

A variety of activities occur in the body during this stage, which lasts between 105 and 120 minutes. At this point, you experience:

This is also when sleepwalking, night terrors, and bedwetting may occur.
Since this is the deepest stage of sleep, it’s harder to wake up, and once you do, you may feel groggy for 30-60 minutes. NREM Stage 3 makes up about 25 percent of total sleep time.

Older adults usually do not get as much deep sleep because they tend to sleep lightly during this time. They spend more time in NREM Stage 2 sleep. Although older adults tend to get shorter periods of sleep due to their age, studies show that they still require as much sleep as they did when they were younger.

Deep Sleep Disruptors

Although deep sleep is crucial for the body, certain factors can prevent you from getting the amount of deep sleep that you need. For example, you may not get enough deep sleep if you toss and turn in your sleep throughout the night or have a job that requires you to work in shifts, and you sleep during the day. Jet lag or frequently traveling between time zones can also interfere with your deep sleep stage.

Other factors that can cause sleep disturbances include:

Just as you may feel tired due to disruptions in your sleep, you can also feel tired if you get too much sleep.

After NREM sleep, you move into REM sleep.

What Is REM Sleep?

REM sleep typically occurs 90 minutes after you fall asleep, and a lot of activity occurs during this time. For example:

• Your breathing muscles are active, and your breathing may be irregular and erratic.

• Dreams occur because your brain is highly active during REM sleep. However, your skeletal muscles are generally paralyzed during REM sleep to prevent you from acting out your dreams.

• Your brain repairs itself and processes emotional experiences. REM stimulates the area of the brain that regulates learning and memory. For example, in this stage, short-term memories are transferred into long-term memories.

REM also helps you concentrate and regulate your mood.

REM takes up about 25 percent of total sleep time.
After REM sleep, you typically cycle back through the NREM sleep stages before returning to REM sleep. The NREM-REM sleep cycle repeats several times throughout the night.

Are You On The REM Rebound?

When you are deprived of REM sleep, meaning you get less than seven hours of sleep per night, you may spend more time than usual in the REM stage. That’s because your body is on the “REM rebound,” trying to compensate for missed sleep and restore balance to your sleep cycle.

Significant stress and drug withdrawal can also lead to REM rebound.

Other signs that show you are on the REM rebound include:

The good news is that REM rebound sleep usually decreases when you improve your overall sleep.

Having Sleep Problems? Visit Your Doctor

It’s common to experience sleeping problems periodically due to life events or medical conditions. However, if your sleeping problem persists, healthcare professionals recommend that you see your doctor.
Before going to your doctor, it’s recommended that you keep a journal and record your sleeping habits, such as:

Also, tell your doctor if you regularly “oversleep,” which means sleeping longer than usual. Although you may occasionally oversleep as a way of catching up on your sleep, there may be an underlying cause for chronic oversleeping. Your doctor may order tests to make a proper diagnosis for your sleeping problems.

Source Links:

https://www.healthline.com/health/oversleeping#complications
https://www.webmd.com/sleep-disorders/sleep-101
https://www.ninds.nih.gov/health-information/public-education/brain-basics/brain-basics-understanding-sleep