The Remarkable Effects of Sleep

Sleep seems like such a simple thing but the effects of sleep are critical. Yet we cannot thrive or survive without it. Just one night of poor sleep has consequences that most of us are unaware of. Discover the incredible impact of sleep on our physical and mental well-being. Find out what happens to the systems in the body when sleep is withheld.

In our fast-paced, productivity-driven society, sleep frequently takes a backseat to other demands. Many of us underestimate the importance of quality sleep and often overlook its impact on our health. A common misconception in industralised societies is that sleep is a luxury rather than a necessity.

The truth is that adequate, quality sleep is a cornerstone of good health. It directly affects both our physical and mental well-being. Science has shown that there is no part of your body or vital functions that is not affected by sleep. Brain, heart, immune system, metabolism, inflammation, digestion, mood… you name it. Sleep impacts your energy levels, stress levels, your likelihood of developing chronic illnesses, and even your likelihood of crashing your car.

We discussed the effects of sleep on productivity (specifically cognitive processes such as learning, memory, problem-solving, and creativity) in another article. This time, we will look at sleep’s numerous effects on physical and mental health and well-being.

“A good laugh and a long sleep are the best cures.”

Sleep is far from a state of passive stillness. There is a whole lot of activity going on to repair and restore many parts of your body while you lie blissfully unconscious. For example, the repair of muscle injuries occurs during sleep. And we now know that sleep removes toxins in your brain that build up while you’re awake.

Throughout your body, organs, and systems are impacted by sleep or lack thereof. Very simply, they are enhanced when you get sufficient sleep and impaired otherwise. Let’s take a peek at what happens across your body as you slumber… and when you don’t.

Effects of Sleep on our immune system

Your immune system is an amazing and incredibly complex thing. It defends against germs and harmful substances, heals wounds, and protects you from illness. When it doesn’t function well or goes crazy (as with a severe allergic reaction), it can kill you. Sleep and the immune system are closely connected. If you don’t get enough sleep, your immune system doesn’t function as well. This means you’re more likely to get sick, among other things. Studies have shown that those who chronically get less than seven hours of sleep a night are three times more likely to get sick from the common cold. This is compared to those who routinely get eight or more hours of sleep.

Sleep can also affect the effectiveness of vaccines. Studies have shown that when people don’t sleep the night after receiving a vaccine, the body’s immune response is weaker. In some cases, even requiring a second dose of the vaccine.

Moreover, lack of sleep can throw your immune system off balance, such as by overreacting. In one study, it was found that sleep deprivation made individuals with peanut allergies more likely to have an allergy attack. Deprivation lowers the reaction threshold to peanut exposure which triggers an allergic reaction by 45 percent.

Sleep on inflammation

Zooming into a specific function of the immune system, we encounter inflammation. Inflammation is our body’s natural response in defense against injury or illness. It’s an effective defense, but it is meant to be temporary. Unfortunately, most of us experience persistent, low-grade, unhealthy inflammation thanks to aspects of our modern lifestyle such as stress, poor diet, pollution, and of course, poor sleep.

It’s been shown that too little as well as too much sleep can raise levels of inflammation in the body. Worse still, just one night of poor sleep can make your inflammation levels spike. Moreover, the effects are long-lasting, and trying to catch up on sleep will not reverse these negative effects.

Persistent inflammation takes a toll on the body, causing accelerated aging and leading to chronic conditions such as heart disease, diabetes, obesity, cancer, stroke, even Alzheimer’s, and depression.

Effects of Sleep on brain health

We mentioned earlier that waste is removed from the brain during sleep. So what happens when the waste removal process is incomplete or deficient? A growing body of evidence is showing strong links between disturbed sleep, sleep disorders, and adverse brain health, ranging from cognitive performance to stroke to neurodegenerative diseases (NDD). One study, published in 2023, looked at the health records of more than one million individuals from the UK, Wales, and Finland. The researchers found that sleep disorders such as sleep apnoea were linked to the risk of Alzheimer’s disease, dementia, Parkinson’s disease, and other NDDs. Moreover, it was discovered that poor sleep can even undo the benefits of “good genes” that lowered an individual’s risk for developing NDDs. An American study found that compared to sleeping 7-8 hours a night, sleeping fewer than 5 hours per night made a person twice as likely to develop dementia.

It is during sleep that our brains have the chance to flush away waste that accumulates during waking hours. Included in the waste are amyloid-beta proteins and tau proteins, both of which have been linked to brain damage in Alzheimer’s and other neurological diseases. Just one night of poor sleep caused an increase in amyloid-beta, while one week of the same led to an increase in tau, (a brain protein that has been linked to brain damage in Alzheimer’s and other neurological diseases).

When poor sleep causes a buildup of beta-amyloid protein in the brain, inflammation develops and starts to impair deep, slow-wave sleep. This makes it harder to sleep which then causes more accumulation of waste and more inflammation. A vicious cycle soon sets in.

Effects of Sleep on mental health

It probably comes as no surprise that otherwise healthy people can experience increased anxiety and distress levels following poor sleep. We’ve all had that miserable feeling where we’re exhausted, groggy, and in a bad mood after a night of lousy sleep. Imagine when that is repeated night after night, month after month. Just like neurodegenerative disorders, mental health and sleep have a circular relationship. Sleep issues can worsen mental health conditions, and mental health problems can lead to poor sleep.

Most people who have a mental health condition have some form of sleep disorder. It applies the other way around too. For example, people with insomnia are twice as likely to develop depression as people who don’t have sleep disorders. Disturbances in sleep patterns are present in 80 percent of people with schizophrenia.

Sleep has demonstrated links to depression, anxiety, bipolar disorder, and other conditions. For those with bipolar disorder, sleep deprivation tends to exacerbate symptoms. Those with insomnia are roughly ten times as likely to have major depressive disorder as those without sleep problems. In patients with schizophrenia, severe disturbance of sleep has been observed to occur before episodes of psychosis. Insomnia also doubles the risk of a person developing anxiety disorders.

Effects of Sleep on Metabolism

If you’re aiming to lose weight, in addition to diet and exercise, you should focus on one more area: sleep. Once again, the connection between sleep and weight works in both directions. Good quality sleep aids in weight loss while lack of sleep or poor sleep contributes to weight gain.  Sleep is intricately connected to various hormonal and metabolic processes in the body, and influences weight, appetite, insulin, and more. Studies that followed groups of people over many years found that short sleep duration or sleep deprivation increased the risk of developing type II diabetes. Chronic sleep loss also puts one at increased risk of obesity, and this applies to children, adolescents, and adults alike.

In addition, when we don’t get enough sleep, we tend to eat more and make fewer healthy food choices. Our bodies tend to store fat rather than burn it. When you are short of sleep, the hormone that makes you feel hungry – ghrelin – is increased, while the hormone that makes you feel full (and stop eating) – leptin – is decreased. This makes you hungrier than usual and more likely to overeat.

Good night, sleep tight

Thinking about the many benefits of sleep and the alarming consequences of insufficient and poor sleep, one wonders why modern, enlightened humans like us knowingly choose to deprive ourselves. Adults require seven to nine hours of sleep every night. If nature dictates that we should spend one-third of our lives asleep, it stands to reason that it must be pretty darn important; as important as food and water.

Science has shown us that sleep is a cornerstone of good health. So why should we mess with our own well-being by shortchanging ourselves of sleep? For most of us, sleep is a modifiable risk factor that can keep illness at bay. Let’s not forget that good sleep also just makes us feel great like we can tackle whatever the day throws at us. So if you have problems with sleep, don’t delay seeking medical help. If you’re otherwise healthy but wish to carve out more time for yourself and your sleep, talk to us. As psychologists and coaches, we can guide you toward optimising your health and performance while helping you tackle shortcomings or self-sabotaging behaviours.

Get in touch with us today.