Have you ever truly thought about how magnificently your body is “made”? Your body system is designed to work in harmony and to heal while you sleep. Imagine that!
“Sleep services all aspects of our body in one way or another: molecular, energy balance, as well as intellectual function, alertness and mood,” says Dr. Merrill Mitler, a sleep expert and neuroscientist at the National Institutes of Health.
Today we’re going to look at how our bodies heal during sleep, and at what point healing and rejuvenation, or restoration of our bodies occur.
Two Types of Sleep (REM, NREM)
As we learned in one of my recent articles, “Sleep Patterns for Adults – What’s Normal?“, there are two types of sleep, REM and NREM. Rapid-eye-movement sleep and non-rapid-eye-movement sleep. Healing and body restoration happens in both types of sleep.
There is one stage of REM sleep, while there are three stages, stage 1, stage 2, stage 3, or three levels of NREM sleep, as you see in the diagram to the right, “Sleep Stages – REM, NREM”.
Several cycles of these stages will occupy our sleep period, which is our seven to eight hours of sleep, as seen in the diagram below, “Stages of a Normal Sleep Cycle.”
During REM sleep, our brain is almost as active as it is when we are awake, however, our closed eyes are in a rapid-eye-movement state. In this phase of sleep, breathing can become fast and irregular, and our blood pressure increases as we transition from NREM to REM sleep when we’re preparing to awaken.
Rapid-eye-movement (REM) sleep occurs in cycles of about 90-120 minutes throughout the night, and accounts for up to 20-25% of total sleep time for adults. REM sleep dominates the latter half of the night, or sleep period, especially the hours before waking.
REM sleep occurrences, the first of which may last only one to five minutes, generally become longer through the night, as seen in the diagram below.
What parts of our bodies are healed or restored during REM sleep?
Our REM sleep supports daytime functions by helping restore energy to the brain and body. REM sleep is the most important stage of sleep for memory, for infants through adulthood, as discussed in my article, “How Do Babies Sleep? 5 Fascinating Facts to Know“, and enhances learning and consolidates new information we’ve learned. REM sleep is also vital for emotional health.
During a typical night, stage 3 of the non-rapid-eye-movement (NREM) sleep, occupies less time in the second cycle than the first cycle and may disappear altogether from later cycles. Note that as the night progresses, sleep cycles do not repeat in stage order as you can see by the diagram directly above.
Our NREM sleep accounts for 40% of total sleep time. During this phase our blood pressure drops and our breathing becomes deeper and slower.
What parts of our bodies are healed or restored during NREM sleep?
Our NREM, Stage 3 sleep, our deepest level of sleep, is essential for muscle recovery and for restoring the body. It is our healing sleep.
Our brain is resting with very little activity, so the blood supply available to our muscles increases, delivering extra amounts of oxygen and nutrients which promote their healing and growth. Muscles and tissues are rejuvenated during this phase of sleep.
Hormones for Optimal Health
When it comes to motives for getting a good night’s sleep, we don’t usually think about our body’s hormones, but the human body secretes and circulates some 50 different hormones, which are released into the bloodstream.
Sleep allows many of our hormones to replenish, so we have the optimal energy, immunity, appetite and coping ability to face the day’s highs and lows.
Hormones for Growth and Repair
When we sleep, our bodies restore and repair various functions and replenish hormones to a healthy level.
During sleep, several of the body’s hormones enter the blood system to circulate throughout the body and activate target cells. These include growth hormones (GH), which are essential for growth and tissue repair.
GH stimulate protein synthesis, which is when cells make proteins, and increase fat breakdown to provide the energy necessary for tissue growth.
At the onset of deep sleep, or stage 3 NREM sleep, our growth hormones, stimulate the growth of essentially all tissues of the body, including bone. Growth hormone functions to regulate body composition, body fluids, muscle, mental function, and possibly heart function.
Sleep During Surgery Recovery
Below are four benefits of a consistent good night’s sleep during recovering from surgery.
- Promotes hormones for tissue growth
When we close your eyes and fall asleep, our brains can attend to other issues within our body. If there are areas that need to heal, the brain can trigger the release of hormones that encourage tissue growth to repair blood vessels. This helps wounds to heal faster, but also restores sore or damaged muscles.
While we sleep, our bodies can make more white blood cells that can attack viruses and bacteria that can hinder the healing process.
Our immune systems rely on adequate sleep to be able to fight harmful substances. When we don’t get enough sleep, our immune system is not able to properly protect the body from infection.
- Gives the body a break
When we sleep, there are fewer demands made on our heart. Our blood pressures will drop and our hearts will be able to take a break. Sleep also causes the body to release hormones that can slow breathing, and relax other muscles in the body. This process can reduce inflammation and assist with healing.
- Provides an energy boost
When we sleep, the demand for calories is decreased, so our bodies are able to replenish and be ready for action when we awake. Interestingly, when we sleep, the level of the hormones that make us feel hungry or full fluctuates. If we don’t get enough sleep, our hunger hormone levels, known as ghrelin, go up and our “full” hormone levels, or leptin, go down. So poor sleep patterns can lead to overeating and eventual obesity. It is best to let our bodies keep everything in proper alignment with a good night’s sleep.
- Helps with a positive attitude
When we are awake, there are many demands on our bodies and our brains. These demands decrease dramatically when we go to sleep. Our bodies and minds can focus on restorative tasks and get a break.
When we awake after a good night’s sleep, hormone levels, energy levels and stress levels have all been adjusted for a more positive start to the day. During sleep, the body is refreshed and more prepared to face the challenges of a new day instead of feeling defeated and stressed. This positive mood can also boost recovery outcomes.
Sleep During Injury Recovery
You’ve probably also heard how sleep is important for injury recovery. People often fail to think about the importance of sleep as part of an injury recovery process.
Because our muscles and tissues go through a repair and rejuvenation process as we sleep, if we’re not getting a consistently sufficient amounts of sleep each night, it’s going to be harder for our bodies to bounce back from an injury.
The amount of sleep needed per night varies from person to person, but in general, most adults should aim to sleep somewhere between seven and nine hours each night.
- Increased blood flow to Injury
One of the reasons why sleep is so important to proper injury recovery is because as we fall into the deeper stages of sleep, our muscles will receive an increase in blood flow, which brings along oxygen and nutrients that help recover and repair muscles and regenerate cells.
As we read earlier in this article, hormones play an important role in injury recovery too. When the body enters its deep sleep stage, non-rapid-eye-movement (NREM) sleep, the pituitary gland releases growth hormones that stimulate muscle repair and growth. When the body doesn’t get enough sleep, the secretion of this growth hormone declines, and it can become harder for your body to recover from injuries.
The hormone prolactin, which helps regulate inflammation, is also released while sleeping. If we don’t get enough sleep, we’re more likely to experience inflammation in the body, which can make injury recovery more difficult, while also putting us at risk of further injury.
We can see from this article just how amazing that during sleep, our brains tell our hormones to secrete the necessary chemicals to the “needy” cells of our bodies for healing. And how neat that even during the lightest stage of sleep, our REM, rapid-eye-movement sleep, our bodies are healing and being rejuvenated.
What I’ve learned from doing research for writing this post: I’ve really enjoyed my research for writing this article about how we heal while we sleep. I didn’t realize how much our bodies undergo daily healing during sleep, whether it’s the day-to-day rejuvenation of our bodies, or the healing of injuries or of surgery.
Thank you for joining me, and I invite you back again to continue to grow with me in this topic of sleep. Together, as I add more and more research to my site, we will be better equipped to make good sleep choices and decisions that will increase our well-being and our quality of life.
As I close, I welcome your thoughts, your needs, or your suggestions regarding sleep as you read my articles. Please leave a note in the comment areas, as I would love to hear from you.
‘Happy Deep Sleep’, and “see” you again soon! Bye for now.