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Sleep can help restore your energy levels and aid in healing both physical and cognitive damage. Using a portable sound machine can make a big difference in how much sleep you get each night.
There are four sleep stages, and each plays a crucial role in allowing you to wake up feeling refreshed. Although all the sleep stages are necessary, deep sleep is especially important for brain health and function. So, how much deep sleep do you need to truly feel rested and healthy?
As an adult, you need between 7 and 9 hours of sleep each night. While you sleep, your body goes through different stages of the sleep cycle. Deep sleep is the stage where you need to feel refreshed when you wake up in the morning. Unlike rapid eye movement (REM) sleep, deep sleep is when your body and brain waves slow down.
Sleep is categorized into two classifications: REM and non-REM sleep. You start the night in non-REM sleep, followed by a brief period of REM sleep. This cycle continues throughout the night, about every 90 minutes.
Stage 1 of non-REM sleep goes on for several minutes as you transition from being awake to being asleep.
During stage 1, your body functions, such as heartbeat and eye movements, begin to slow down. Your muscles also tend to relax with only occasional twitches, and your brain waves begin to slow down from their wakeful state.
Stage 2 comprises about 50 percent of the total sleep cycle. This is where you may fall into more than any other throughout the night.
During stage 2, your body’s systems continue to relax and slow. Your body temperature drops, and your eye movement stops. In this stage, your brain waves are slow, but you still have some short bursts of activity.
Stages 3 and 4 are periods where you experience deep sleep.
During these stages, your breathing and heartbeat are at their slowest as your muscles relax. Your brain waves also become the slowest they will be while you’re sleeping. In this stage, it is difficult for you to wake up even with loud noises.
Deep sleep is also often referred to as “slow wave sleep” (SWS). The first stage of deep sleep lasts for about 45-90 minutes. In the first half of the night, it lasts for longer periods and becomes shorter with each sleep cycle.
The first stage of REM sleep, or stage 5, occurs for about 90 minutes after moving through non-REM stages.
During stage 5, your eyes move rapidly from side to side, and you experience dreaming as your brain activity increases to a more wakeful state. In this stage, your heart rate also increases to near its wakeful state, and your breathing becomes faster and may be irregular at times. Your limbs may also become paralyzed.
Why Deep Sleep Is So Crucial for Your Health
Having quality deep sleep is essential for your overall well-being. During this stage, your brain is recovering from all the activity it went through during the day. For children and teenagers who are still developing, deep sleep is important since there’s an increase in growth hormone secretion during this stage of sleep.
During deep sleep, glucose metabolism in the brain increases, supporting short-term and long-term memory and overall learning. It is also the stage where your pituitary gland secretes vital hormones, such as human growth hormone. Benefits of deep sleep include:
Cell regeneration
Energy restoration
Increasing blood supply to muscles
Promoting growth and repair of tissues and bones
Strengthening your immune system
One of the most significant functions of deep sleep is the consolidation of new memories. This is typically referred to as sleep-dependent memory processing. People with insomnia or some other sleep disorder suffer a disability of this function.
As you grow older, the amount of deep sleep you get reduces, which makes it all the more important to have enough sleep through the night. Some of the most important body and brain functions occur during deep sleep. Not getting enough sleep can lead to the development of conditions such as:
Heart disease
Obesity
Diabetes
Hypertension
According to studies, you spend about 13 to 23 percent of your time asleep in deep sleep. You spend roughly 75 percent of your rest in non-REM sleep and the other 25 percent in REM sleep.
You should get enough deep sleep to allow your body and brain to repair themselves. This will help you feel restored. The amount of deep sleep you have will relate to how much overall sleep you get. Sleeping 7 hours or more is recommended for most adults, which will usually give your body plenty of time in the deeper states of sleep.
If your body does not get enough sleep, it will compensate the next time it can get sleep by quickly moving through the cycles to reach the deepest levels of sleep more quickly and stay there longer. If you regularly do not get enough deep sleep, it may affect your brain.
With that being said, deep sleep tends to decrease with age. If you’re under 30 years old, you may get two hours of deep sleep each night. If you’re over 65, you may only get a half hour of deep sleep or none at all each night.
If you always wake up feeling less than refreshed or groggy, there’s a chance that you’re not getting enough deep sleep. Not having enough deep sleep can lead to unwelcome symptoms such as:
Irritability
Daytime fatigue
Inability to focus
Increased hunger
Being short-tempered
Regularly experiencing these issues despite getting enough hours of sleep could be a sign that your sleep quality is lacking.
To measure sleep quality, a medical device such as an electroencephalograph (EEG) is used due to its accuracy. You can also measure your deep sleep with a polysomnography (PSG) test, also referred to as a sleep test, which measures brain activity with an EEG. During PSG, you’ll sleep at a lab while hooked up to monitors that measure:
Oxygen levels
Breathing rate
Body movements
Heart rate
Brain waves
In an EEG test, electrodes are placed on your scalp to measure electrical activity in your brain.
It can show you your delta brain wave activity, which is the defining aspect of deep sleep. It also allows you to go right to the source and obtain the raw data.
Most sleep trackers use heart rate and breathing as a surrogate for estimating sleep. Therefore, most trackers only make an approximation as to how much you’re actually sleeping. To obtain exact data on your sleep habits, an EEG device is recommended.
Wearable devices are also available on the market to track your body’s movement during your sleep. While these devices may help identify sleep patterns, they may not be a reliable indicator of how much deep sleep you’re getting.
The best way you can increase your amount of deep sleep is to give yourself adequate total sleep time. In addition to this, here are some ways to get more deep sleep.
Studies show that regular exercise can improve and increase the quality of your sleep deep. People who work out during the day tend to fall asleep faster than those who don’t exercise at all.
And contrary to popular belief, the timing of your workout isn’t as important as you think. If the only time you have to exercise is in the evening, it can still help you get a good sleep. Just make sure you avoid strenuous workouts right before you go to bed.
Having a healthy diet can provide you with lots of benefits, including getting quality sleep at night. Eating more sugars and fats and less fiber can disrupt your sleep.
It is recommended to consume more foods rich in fiber. Eating more fiber can result in more time spent in the stage of deep sleep. During the day, make an effort to add more fiber to your diet in addition to other foods that promote good sleep.
Caffeine can make it harder for you to fall and stay asleep, and it can also reduce the amount of deep sleep you get. It’s important to avoid caffeine at least 7 hours before you sleep to have a good night’s sleep. Instead, only drink water or tea. Chamomile or warm milk can also help induce sleep.
Being stressed from your work can make it difficult to turn your mind off and enjoy sleep. Having a bedtime routine can help your body relax and cure any looming sleep anxiety.
Your bedtime routine can include meditation, journaling, or reading books. It should be anywhere from 30 to 60 minutes, and the key is to keep your habit consistent. This will train your mind to associate the routine with sleep and make you productive the next day.
The bed where you lie your head at night should be sleep-friendly. When sleeping, your bedroom should not have bright lights, loud noises, or a cooler temperature. The perfect temperature for sleep is between 60 and 67 degrees Fahrenheit.
On your bedside table, use only low, amber light bulbs and avoid using electronic devices at least an hour before sleep. It’s also important to make sure that you have a comfortable mattress that supports you when you sleep.
If you struggle to sleep at night, try listening to some white or pink noise. Sound plays an important role in your ability to fall and stay asleep. These sounds will block any sound that may be keeping you from falling and staying asleep.
If you want to increase your deep sleep, pink noise is calming nature sounds like waves crashing on a beach or rainfall. This noise can increase deep sleep and improve memory in adults.
Deep sleep is one of the most crucial stages of sleep. From replenishing your energy to balancing your hormones, it plays a vital role in recovering your body.
While the exact amount varies by age and health, most adults need around 1.5 to 2 hours of deep sleep each night—which comes naturally when you consistently get 7–9 hours of quality sleep.
Understanding how much deep sleep you need and taking steps to protect it is key to restoring your energy and improving your well-being.
