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  • Writer's pictureTatiana Phillips

The Night Shift: How Your Body Repairs Itself While You Sleep

A woman sleeping. Her brown hair is spread out over the bed. Her face is partially covered by her blanket.

Everyone needs a good night’s rest. But if you are one of the 36% of Americans who don’t get a good night’s sleep, you may want to read further. How your body repairs itself while you sleep is crucial for maintaining proper health. 

Without proper sleep, your body is at a higher risk of developing heart disease, stroke, diabetes, dementia, mood disorders, and obesity. There are various reasons why one might not sleep well or stay asleep for very long; however, regardless of the cause, understanding how your body repairs itself while you sleep may change your habits. Each night, our sleep cycles from light sleep to deep sleep. Every stage of that cycle is crucial for your health.

A chart of sleep cycles through the night. It spans from 10 pm to 6 am. It shows six cycles between those hours with lightest sleep, light sleep, deep sleep and REM sleep.

Deep Sleep: Cellular Repair

The first few hours of sleep is when your body repairs cells. The cells that repair while you sleep are needed to regenerate tissues, including muscle and bone. Everybody needs tissues to regenerate to process food, heal internal organs, repair any wear and tear on our joints and muscles, and grow new cells for any we have lost.

Deep Sleep: Brain Detoxification

At the same time as cellular repair, your brain processes everything it consumes from the day. While your brain consumes information, it produces toxins. “The waste removal system of the central nervous system – called the glymphatic system – needs you to do your part to detox your brain. It gets the majority of its brain-cleaning duties done during our sleeping hours. When we don’t sleep well, it can’t keep up. Too much cellular waste can pile up, including excess amyloid proteins—the primary protein associated with an Alzheimer’s diagnosis. Our cerebral spinal fluid acts as a flushing system for brain detoxification each night, says Dr. Alberto R. Ramos. This fluid essentially takes out the garbage at night.” When your brain processes the pieces it no longer needs, it creates space between the neurons, allowing your brain to lose those pieces.

REM Sleep: Memory Consolidation

Rapid eye movement, or REM cycles, comes after deep sleep, which lasts a few hours. REM cycles are when the body is immobile, but the brain remains active. This part of the sleep cycle is when you may experience wild dreams or nightmares. During this phase, our brains are overly active in processing information, consolidating memories, and transferring information from short-term to long-term memory. “If you cut your sleep hours short, most of what you've deprived yourself of is REM sleep," said Dr. Michael Grandner, director of the Sleep and Health Research Program and an associate professor in the Department of Psychiatry at the University of Arizona College of Medicine in Tucson. “That can interfere with learning, memory, and mood, which are all regulated during this stage of sleep. Studies show people deprived of REM sleep have trouble remembering things they learned before falling asleep. The last stage of sleep is when more mental recovery and healing occur, Grandner said. But it's also when the body finishes the physical recovery work begun during deep sleep.”

Your sleep cycle continues through each phase between REM and light sleep, but the time you spend in the REM stage and deep sleep shifts. Throughout your sleep cycle, you spend less time in the deeper stages of sleep. When your sleep cycle is disrupted, it throws off the rhythm you need to rebuild and recover. 

Additional Ways Your Body Repairs Itself While You Sleep

Your body not only processes the wear and tear you experience daily but also promotes immune system support, hormone regulation, and the repair of free radical damage. Those key elements are needed to help you maintain a healthy weight, protect you from colds and viruses, and process stress.

Immune System Support

If you have ever wondered why after you spend time traveling, whether, on a road trip or a flight, you sometimes might come home feeling run down, it is because your body lacks the rest it needs. The same can be said of days when you spend more time at work than home. “Lack of sleep can affect your immune system. Studies show that people who don't get quality or enough sleep are more likely to get sick after exposure to a virus, such as the common cold. Lack of sleep can also affect how fast you recover if you get sick.”

Hormone Regulation

Our sleep patterns affect hormone regulation in such a monumental way that too little or too much sleep can create dramatic health issues. Missing sleep can lead to reduced immunity, more frequent infections, illnesses, appetite spikes, higher calorie consumption, and weight gain. Too much sleep can lead to grogginess, daytime fatigue, reduced metabolism, impaired focus, and disrupted sleep cycles. That is why it is essential to try to go to bed at the same time every night and wake up every day at the same time.

Free Radicals

There needs to be a little bit of a science lesson to understand the effects of sleep and free radicals. Our bodies contain atoms that have atom layers (to make a shell) that need a certain amount of electrons within those layers. If an atom doesn’t have a full shell, it might bond with another atom to fill that void. Those atoms combined are what we call free radicals. Because the shells lack electrons, they make the atoms unstable. Unstable atoms are what cause aging (wrinkles) and diseases. The decreasing free radicals occur when we sleep due to the antioxidants that form during our sleep cycle. When there is an imbalance of antioxidants and free radicals, this can cause damage to the organs and tissues in your body, leading to diseases such as diabetes, hypertension (high blood pressure), heart disease, cancer, and even Parkinson’s and Alzheimer's. 

When we sleep, we don’t just allow our minds and bodies the rest we crave; we enable our bodies to process and repair in ways that may not be noticeable after one or two days of poor sleep. Our brains may be foggy, or our appetite may change. But we can see the effects of a poor night’s sleep over some time. What happens internally may take a more considerable toll on our overall health. From cellular repair and brain detoxification to immune system support and free radicals, our bodies work incredibly hard to keep us functioning throughout the day and to try to keep us as healthy as possible. How your body repairs itself while you sleep is vital to a long-lasting, healthy life. So, the next time you decide to stay up later than usual or push through when you’re tired, think about the long-term effects of poor sleep. A good night’s rest may mean less health concerns later on.

If you are struggling with healthy sleep, we have a few tips you can use today.

An infographic with tips to improve your sleep. Each tip has an icon graphic to accompany.


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