Side effects of lack of sleep sometimes go unnoticed, and yet they are prevalent.
Working evening and night shifts disrupt your natural biorhythm. They are recognized as also being responsible for several types of cancer by the World Health Organization (WHO).
As a general rule, the side effects of lack of sleep often go unnoticed. However, sleep deprivation can have some serious health implications, including diabetes, lower immunity, higher cancer risk, Alzheimer’s disease, heart problems, food cravings, elevated cortisol levels and ultimately, death.
If you are sleep-deprived, put on your pajama pants and read no further. Turn off the lights, close the curtains, and good night!
That’s probably the best thing you can do for your lifestyle. However, everyone else, who is nicely rested, read on to discover the severe implications of sleep deprivation for our health.
Table of Contents
- 1 Side effects of lack of sleep: Introduction
- 2 Impact of sleep deprivation on our health
- 3 Why we need sleep
- 4 How much sleep do we need
- 5 The basics of sleep
- 6 Side effects of lack of sleep: Conclusion
Side effects of lack of sleep: Introduction
You would think that most car accidents occur because of driving under the influence of alcohol or drugs. But most happen because of dormant driving and are usually even more serious.
When you have consumed alcohol, your ability to react may have slowed down, but you can still respond to something.
There is no responsiveness if you are taking a micro-sleep (that’s a mini-sleep) behind the wheel.
It’s like having a limp puppet behind the wheel. Nothing happens and the consequences are all the greater.
Source: Tefft, Prevalence of motor vehicle crashes involving drowsy drivers, United States, 1999–2008, Accident Analysis & Prevention, 2012
Impact of sleep deprivation on our health
Not getting enough sleep is no laughing matter, as the below health implications of a lack of sleep will illustrate.
Sleep deprivation contributes to the explosion of diabetes worldwide
Blood sugar, insulin, and other hormones related to energy metabolism operate on a 24-hour rhythm that is easily disrupted by working a night shift.
Most people think you can only raise blood sugar by overeating sugar or starch or by not burning it enough.
Research shows that your sugar levels after a meal depend not only on the quality of that meal but also on its timing.
For example, two identical meals produce a very different response in blood sugar if you eat one in the morning and the other in the evening.
Eating late at night is detrimental and produces much higher sugar spikes. Eating during the day is the best thing there is. Then our metabolism is set to its maximum to digest food.
In contrast, our metabolism is much slower at night, and therefore we burn slower. This has to do with our natural sleep hormone, melatonin.
If we take proper account of our biorhythms, that is, no excess light or artificial light just before bedtime, our bodies will start to produce melatonin two to three hours before bedtime.
Melatonin binds with receptors in the pancreas and signals that it is time to sleep and no insulin is needed. Therefore, natural insulin production is put at a deficient level.
Suppose you binge eat late in the evening or at night. In that case, your sugar levels will remain elevated because there is no insulin to store sugars quickly and efficiently. So your body is not set up to eat late.
Healthy volunteers were exposed to one week of only four, five, or six hours of sleep. Purely due to less sleep, their muscles could only absorb half the average amount of glucose.
If the muscles don’t absorb glucose, the blood glucose level rises, and you put someone on the verge of diabetes. Simply and solely by sleeping less. How is this possible?
For a good balance in your blood sugar, you need a good release of insulin and cells that are sensitive to insulin‘s message and absorb glucose properly.
Too little sleep causes things to go wrong on both sides of that balance. For example, beta cells in the pancreas no longer respond to the glucose spike. Thus, less insulin is released.
This wouldn’t matter so much if the body cells were susceptible to the message of that little bit of insulin, and you could still clear some of that blood glucose.
Unfortunately, this is not happening either. Instead, the cells stop sucking up glucose from the bloodstream. Then, on both sides of your blood glucose balance, you’re screwed.
Sleep deprivation means you don’t have enough insulin, and what is left doesn’t work well. The sugar gate of the cells remains closed, and glucose accumulates in the bloodstream.
This is actually mind-boggling. Thus, sleep deprivation directly affects our body cells and the functioning of those cells (explaining why good sleep hygiene is essential).
It is now recognized that chronic sleep deprivation contributes substantially to the global explosion in diabetes.
It is often invisible, but actually very easy to do something about, as long as you are able to recognize the problem in yourself.
- Feychting, et al., Reduced Cancer Incidence among the Blind, Epidemiology, 1998
- Spiegel, et al., Impact of sleep debt on metabolic and endocrine function, The Lancet, 1999
Lower immunity, higher risk of cancer
In a 2013 study, healthy volunteers were limited to six hours of sleep per night. This is pretty much what most of us consider normal nowadays.
They looked at the change in gene profile compared to a control group that slept eight hours.
They saw that over 700 genes showed disrupted activity in the group with only 6 hours of sleep.
With about 20,000 genes in total, this means that a change occurred in roughly 3% of the genes.
The genes that were inhibited in their activity were genes related to immunity and resistance.
The more activated genes were related to tumor growth (cancer growth), long-term inflammation, and genes linked to stress and thus cardiovascular disease.
So sleep deprivation also makes you more susceptible for cancer to spread or even getting cancer in the first place.
Source: Möller-Levet, Effects of insufficient sleep on circadian rhythmicity and expression amplitude of the human blood transcriptome, PNAS, 2013
Lack of sleep leads to Alzheimer’s disease
Extensive research was done on the relationship between Alzheimer’s and sleep deprivation. Our brains make a waste called beta-amyloid.
Our nerve cells are flooded with spinal fluid during our sleep to take the amyloid plaques with them in a tidal wave and flush the nerve cells clean.
If we don’t sleep, the amyloid builds up. Research shows that after just one restless night, one has more buildup of amyloid plaques, as evidenced by epidurals from sleep-deprived people.
You can thus find more amyloid in the spinal fluid. If the amyloid plaques continue to build up indefinitely and our brains can’t be flushed clean, we get Alzheimer’s.
Source: Ooms, et al., Effect of 1 Night of Total Sleep Deprivation on Cerebrospinal Fluid β-Amyloid 42 in Healthy Middle-Aged Men: A Randomized Clinical Trial, JAMA Neurology, 2014
Increased risk of cardiovascular disease
Sleep deprivation is partly harmful because it causes overstimulation of the sympathetic nervous system LINK. Your body is then constantly in fight-and-flight mode. Ready to run away.
So with sleep deprivation, you are always in high gear. Compare it to a Lamborghini engine that you put in a small VW Beetle.
At some point, the body can no longer handle the impact of the engine, and the vehicle falls apart. So it is with our bodies.
The constant over-stimulation in our bodies creates a cascade of adverse and unhealthy reactions.
So a sleep-deprived body thunders on without rest and without relief from the brake pedal called sleep. This means that you may suffer from heart palpitations, for example.
More and more uncoordinated blood is rushed through your vessels, putting you at risk for high blood pressure.
The stress hormone cortisol, instead of being nice and low, is dramatically elevated, and this squeezes your vessels. This raises your blood pressure even more.
Added to this is the fact that growth hormone, which usually peaks during your sleep, is barely present.
This is extra unfortunate because, without the healing effects of growth hormone, the smooth lining of your blood vessels does not recover.
All in all, a domino effect resulting in high pressure in damaged vessels. Deep (non-REM) sleep has a calming effect on the sympathetic nervous system.
Deep sleep prevents that constant fight-or-flight response and lowers blood pressure. Thus, sleep deprivation and lack of deep sleep are a nightmare for the cardiovascular system.
Less sleep causes more hunger and less satiety
The less you sleep, the larger your belly size. You gain weight more easily and quickly when you see your bed less often or for a long time.
Invisible forces conspire to fuel your hunger. These invisible forces are our familiar buddies, leptin and ghrelin, the satiety hormones:
- After just one less night of sleep, leptin’s message to stop eating is less audible and you feel less satiated.
- Not only that, but the message to continue eating from our hunger hormone ghrelin actually increases.
So it’s a double-edged sword, more hunger, and less satiety. So you constantly walk around feeling starved.
Also, sleep-deprived people appear to have consistently more cravings for sweet and carbohydrate-rich foods and unhealthy snacks.
A part of the brain (the prefrontal cortex) that allows you to make measured decisions doesn’t work well after sleep deprivation. Instead, you suffer more from impulsive eating.
So it is challenging to reach your ideal weight if your sleep is not one of your top priorities and is one of the direct side effects of lack of sleep.
Why we need sleep
The real underlying reason why we need sleep remains elusive. Of course, we are not eating, caring, working, or reproducing. Instead, we are resting, recovering, and recuperating long and deeply.
Not sleeping can cause you to hallucinate and give you memory problems. Sleep deprivation has essentially the same effect as drinking alcohol.
Not sleeping for more than three nights, not sleeping enough hours per night for an extended period, or poor quality sleep affects your ability to learn and think.
Also, your resilience (or immunity) is lowered. Mood and sleep use the same messengers. When sleep-deprived, you can have the same gloomy feeling as depression.
They are hard to tell apart. It can also continue, and you can start to fluctuate enormously in your mood from ecstatically happy to deeply sad or angry.
Sometimes you may feel that your life is passing you by, and sleep is getting in the way of everything you could be doing.
Many people give up precious sleep hours because there are so many plans and goals to be met.
However, you can’t catch up on sleep easily.
Many long-term sleep-deprived people live in an environment where work and school hours do not match the natural biorhythm (circadian rhythm) of their own bodies.
They don’t make up for the previous night’s sleep deprivation and thus build up a sleep debt that is never repaid.
- Walker, A sleep prescription for medicine, The Lancet, 2018
- Wittmann, et al., Social Jetlag: Misalignment of Biological and Social Time, Chronobiology International, 2006
How much sleep do we need
Doctors and nurses in hospitals know what it is like to survive a shift without sleep as they often work through the night.
They succeed in doing this because of the adrenaline in their body, which keeps their bodies awake.
But this does not always work out well. For example, research shows that one in five doctors make a medical mistake due to sleep deprivation.
It is known that sleep deprivation is used as a non-visible form of torture. Apparently, deliberately preventing someone from sleeping is very effective in making you a vulnerable target.
Amnesty International has also rightly called out this inhumane form of torture.
An American journalist, Seth Maxon, decided on a whim to experiment with his own sleep when he was eighteen years old.
However, he doesn’t remember how long he ended up not sleeping because he eventually woke up in a psychiatric clinic.
It could be even worse. In 2012, in China, soccer fan Jiang Xiaoshan died after staying awake for 11 days to watch all the European Cup soccer matches.
Also, the Guinness Book of Records took out the record for not sleeping. It turned out to be too dangerous, because sleep deprivation is indeed deadly.
Source: Maxon, How Sleep Deprivation Decays the Mind and Body, The Atlantic: Health, 2013
The basics of sleep
We can go without food for a month, we can go without drink for three days, but we can’t go without sleep.
Sleep is something that almost every living thing does every 24 hours.
Cortisol and sleep
If all goes well, every human being sleeps a third of their life. Our cortisol starts to rise as early as around 2:00 am. The body prepares us for the day ahead.
For example, our cortisol has varying levels throughout the day. In the morning, it should be high to make us bright and alert.
When you go to bed at 10 pm, your cortisol levels are wonderfully low; this is ideal for the tired body that needs to recover properly.
The stages of sleep
Sleep is done in cycles of about 90 minutes. In every cycle of 90 minutes, you go through different stages of sleep.
Deep non-REM sleep cycles (REM stands for Rapid Eye Movement) are most prevalent in the first half of the night.
This deep (non-REM) sleep at the beginning of your sleep is vital for storing everything you learned and did that day. It’s like a save button on your laptop.
If your deep sleep is disrupted or you don’t get enough of it, you have trouble storing new memories.
In contrast, if you lose sleep by waking up early, you actually lose more REM sleep.
This is especially important for processing your emotions. Among young people, lack of REM sleep, i.e., a lack of processing emotions, is the strongest predictor of (attempted) suicide.
Emotional processing and memory functions are enhanced by sleep at different times. So not only is the amount you sleep essential but also at what hours you sleep.
- Walker, Sleep-Dependent Memory Processing, Harvard Review of Psychiatry, 2008
- Seung-Schik Yoo, et al., The human emotional brain without sleep — a prefrontal amygdala disconnect, Current Biology, 2007
- Yu Jin Lee, et al., Insufficient Sleep and Suicidality in Adolescents, Sleep, 2012
We collectively sleep less
Unfortunately, sleep is precisely what the hurried person gives up. In 1942, we slept an average of 7.9 hours a night worldwide. That’s now only 6.31 hours in the U.S. and 6.21 hours in Japan.
After a busy demanding day, we wish to unwind and want some time to ourselves. Perhaps this results in a Netflix binge accompanied by a glass of alcohol.
However, these actually disrupt your sleep pattern.
30% of people suffer from some form of insomnia. Not always because of fewer hours of sleep, but more irregular and restless sleep plays a significant role. As a result, our sleep is more often disturbed.
One factor that can significantly improve the quality of your sleep is a suitable bed frame, especially if you’re a bit heavier.
A firm and comfortable bed frame can make all the difference for a good night’s sleep. Tip: Check out our recommendations for the highest-rated bed frames for a heavy person to really ensure you get all the support you need for an excellent night’s sleep.
Research shows that people who work shifts with night shifts, smoke more, drink coffee and alcohol, are more likely to be overweight and are also more likely to have type 2 diabetes, which are common side effects of lack of sleep.
Side effects of lack of sleep: Conclusion
Sleep deprivation has severe consequences on our health:
- Contributes to diabetes
- Lowers our immunity and resistance
- Increases our risk of getting cancer and promotes the spread of cancer
- Leads to Alzheimer’s disease
- Causes more hunger and less satiety
- Can eventually cause death
In short, the quality of our sleep depends on four essential factors:
- Sleep quantity: the number of hours
- Sleep depth: during the night, we alternate between deep and shallow sleep
- Sleep regularity: ideally, no night shifts and going to bed at set times
- Continuity of sleep: sleeping without waking up all the time
Thus, to avoid the side effects of lack of sleep and their negative health consequences, focus on the above sleep factors and prioritize your sleep to live a healthier and longer life!