Deep sleep, also known as slow-wave sleep, is all our bodies need to function correctly. It is associated with the deepest stage of sleep, where the brain waves are slowest. This sleep period is also known as slow-wave sleep as it produces waves of relatively high amplitude and a frequency of less than 1 Hz. It is the third stage of the non-rapid eye movement sleep cycle; the other being rapid eye movement.
Every adult needs at least 7 to 9 hours of sleep, but the quality of sleep is also equally important. While you sleep, your body goes through different stages of sleep. You need to complete the cycle to wake up fresh in the morning. There are various processes that your body goes through, depending upon what stage of sleep you’re in. With good quality sleep, you feel less tired when you wake up. It is the stage where breathing and heart rate goes down, but your ability to fight germs and form memories goes up. A lack of restorative sleep increases your chances of infection, thinking and memory problems, and other health issues.
Stages of Sleep:
The sleep cycle is divided into two phases:
Every night, you start with non-Rem sleep, followed by a brief period of REM sleep. Each cycle continues about every 90 minutes and lasts throughout the night.
Stage 1: It lasts for only several minutes as the body shifts from awake to asleep. All the body functions like heartbeat, respiration, and eye movements begin to slow down. All your body muscles relax with lapses of convulsions. Likewise, your brain waves slow down as compared to when you are awake.
Stage 2: This stage counts for more than 50% of the total sleep cycle. It is the stage you fall into more than any other throughout the night. All your body’s systems continue to slow and relax. The core temperature of the body falls in this stage. Moreover, eye movements stop, brain waves slow down further, but it might have short bursts of activity.
Stage 3 and 4: This is the stage where you experience deep sleep. At this stage, heartbeat and breathing become the slowest. Your brain waves become the slowest, and all body muscles relax. It’s challenging to awake someone even with loud noises at this stage. It is also referred to as “slow-wave sleep” (SWS) or delta sleep. The first stage of deep sleep lasts from 45 to 90 minutes. It lasts for more extended periods in the first half of the night and becomes shorter with each sleep cycle.
It is stage 5 that occurs about 90 minutes, which means moving through non-Rem stages. In this stage, your eyes move rapidly from side to side. You might be dreaming in a wakeful manner. Your heart rate starts increasing in this phase, and breathing becomes faster, even irregular at times. It is where you feel paralyzed for a while.
How Much Deep Sleep Do You Need?
You spend almost 75% of your night in non-REM sleep and the rest 25% in the REM sleep cycle. Of this, around 13 to 23% of total sleep is deep sleep. The duration of deep sleep decreases with age. If you are under age 30, you may get two hours of deep sleep each night. But if you are above 65, you’ll be lucky enough to get a half-hour of deep sleep each night, or none at all. If not getting any doesn’t indicate a sleep disorder. However, younger people need more because it promotes growth and development in them.
How Will You Know You’re Getting Enough Deep Sleep?
If you wake up and feel exhausted, this is the first sign you’re not getting enough deep sleep. There are some wearable devices available in the market that measure sleep by tracking your body’s movements. It may not be that reliable as it is a relatively new technology. If the outcomes are worse, you may visit your physician. He can ask you to take a test called polysomnography (PSG). During this test, you’ll sleep at the lab while being monitored. The monitors will measure the following:
- Breathing rate
- Oxygen levels
- Body movements
- Heart rate
- Brain waves
Your physician can monitor your report to determine whether you reach the stage of deep sleep throughout the night or not.
Benefits of Getting Deep Sleep:
Glucose is the brain’s food, and glucose metabolism increases during deep sleep, which means that it is the most favorable time for the brain to process its food. If a person gets deep sound sleep, his brain supports his short-term and long-term memory and overall learning. It is also in the phase of deep sleep when the brain secretes its essential hormones, like human growth hormone (HGH), that leads to the growth and development of the human body.
Other benefits of deep sleep include:
- Energy restoration
- Cell regeneration
- Increasing blood supply to muscles
- Promoting growth and repair of tissues and bones
- Strengthening the immune system
What Happens When You Don’t Get Enough of It?
Deep sleep is part of your sleep cycle when the brain processes all the information it receives during the daytime. If you don’t get enough of it, that means your brain is unable to store the word in your memory that you received all day long.
The deep sleep stage is associated with some strange disorders like:
- Night terrors
- Sleep eating
You are more likely to feel sick, depressed, and gain weight when deep sleep is impaired. If you find any of your siblings in such a state, don’t be afraid or humiliate them. Contact your physician at once as these poor conditions of sleep can further lead to:
If healthy sleep is not achieved, chronic sleep loss can lead to irritability, mood swings, and several mental disorders such as depression. It can also be as lethal as increasing the risk of various forms of cancer.
How is Deep Sleep Connected With your Brain?
Your brain has a pattern of waves that change during this sleep cycle. They are called delta waves. Delta waves get slower and bigger during your sleep time. They’re an essential part of how you learn and store memories in your brain.
When you sleep, blood flow to your brain decreases. It isn’t bad, as you might guess; instead, it leaves more room for cerebrospinal fluid (CSF) to flow in and out. That’s the liquid that cushions your brain and spinal cord and protects it from any damage. CSF deems to pitch a ride on your delta waves. It helps clear out the trash from your brain cells compared to what it does when you are awake. Deep sleep also removes beta-amyloid, a protein that is linked to Alzheimer’s disease.
Deep Sleep and Your Immune System:
You might have noticed that you get tired when you’re sick. According to experts, deep sleep stimulates your immune system. That is why you get more deep sleep when you have an infection than when you’re healthy. If you rest, you may get better fast. Also, deep sleep can:
- Strengthen your immune system daily,
- Drop the level of chemicals that cause inflammation
- Help vaccines work in your body.
How Can You Get Better Sleep?
- Heat may promote more slow-wave sleep that is essential for good and deep sleep. For example, taking a hot bath before going to bed or spending time in a sauna may improve sleep quality.
- It is also believed that a low-carbohydrate diet or taking certain antidepressants may also promote deep sleep. However, more research is needed in this section.
- Set your schedule or a fixed time to go to sleep and wake up each day.
- Work out daily. It’s always a good time to take a start, about 20 to 30 minutes is a good start; avoid working out before bedtime.
- Wisely choose your drinks. Avoid caffeine, alcohol, and nicotine-containing beverages, especially before bedtime. You can drink water or other decaffeinated drinks but not even too much of that.
- Create a routine that will relax your mind from the daily busy routine, such as reading a book or taking a bath.
- Avoid bright lights or loud noises in your bedroom. Too much electronic media can ruin your bedtime routine and makes it harder for you to fall asleep. Keep the gadgets away from your sleeping area, not to interrupt your sleep.
- Don’t lay foul in your bed, tossing and turning. Instead, get up and do a little activity like reading or making your cupboard and go back to sleep when you feel like being tired again.
- Consider replacing your pillows or mattress if you’ve had them for over a year and it didn’t comfort you anymore.
- Do not exceed your daytime sleep or nap time by more than 30 minutes. It is enough to restore your energy for the rest of the day.
Therefore, of all the sleep cycle stages, slow-wave sleep (deep sleep) is a crucial part of your cognitive functioning. It plays a significant role in memory consolidation and brain restoration. Because of its importance for your overall health, you must increase your amount of deep sleep by allowing yourself to have enough total sleep time each night. Additionally, exercise and a healthy diet are a couple of different methods you can try to increase your slow-wave sleep.
Until Next Time,
Team Doctor ASKY!