Surprising Ways Sleep Shapes Our Lives

Bon Jovi sang in one of his songs, "Gonna live while I’m alive. I’ll sleep when I’m dead". But if we take these lyrics to heart and start ignoring sleep while alive, we are dead sooner.

If you are like most people, you often sacrifice sleep whenever there is a time crunch. Sometimes it’s an emergency or an important project, other times it’s just a party you don’t want to miss. But is sleep really so inconsequential that you could sacrifice it without thinking twice? Recently, I have dug deep into this question.?

Consider sleep from the lens of evolutionary biology. Evolution helps species strengthen features that help survival and abandon features that hinder survival. Sleep is as ancient as life itself - a feature that has lasted through millions of years of evolution. On the surface, sleep seems to be a poor trait to retain. After all, a sleeping creature is much more vulnerable to predators and during sleep, the important tasks of looking for food and mates are not getting done. But instead of dropping sleep like a hot potato, evolution has deemed sleep so important that all creatures big and small sleep. Marine mammals sleep while swimming, and seabirds nap while flying, but sleep they must. (Pennisi 2021). This fact alone that evolution has given such importance to sleep should give us a pause when sacrificing sleep.

Why do we sleep? The research around this question is still ongoing but we do know an awful lot about sleep. A truncated list of benefits of sleep is presented below - the full list is much longer. These benefits are not anecdotal, these have been proven by hundreds of rigorous studies over the years. Several sources were used to collect this information, most notably Matthew Walker’s best seller “Why we sleep”.?

Sleep restores the brain's capacity for learning, by filing already made memories and making room for new memories. Studies have shown that an individual who pulls an all-nighter has 40% reduced brain capacity to learn new facts the next day compared to a well-slept individual. During deep sleep, slow electrical waves push fluids around cells in the brain to remove waste products. Without adequate sleep, this removal of waste is disrupted, leading to many brain disorders such as depression, Parkinson's disease and Alzheimer's disease. In short, frequent nights of sleep deficiencies can lead to a dumber and forgetful brain that is also prone to serious brain disorders.

Sleep improves athletic performance and motor skills across many sports, and reduces chances of injury (Milewski et al 2014). Sleep deprivation is known to impact response time. That is why when you play tennis after a poor night’s sleep, you immediately notice that your hand-eye coordination is off its peak.?

When sleep deprived, the brain induces micro sleeps - brief moments of lapse in attention and concentration. Alarmingly, we do not even notice the microsleep periods when we are sleep deprived. That lack of sense of your own impairment makes sleep deprivation very dangerous. More people are killed in accidents due to micro sleeps than due to alcohol consumption. The graph below summarizes study results from AAA Foundation. (“Acute Sleep Deprivation and Risk of Motor Vehicle Crash Involvement” 2016)

When you get behind the wheel of a car with 4 hours or less of sleep the night before, you are 11.5 times more likely to get into a crash compared to someone who has slept 7 hours or more. It has been estimated that there is a car accident somewhere in the United States every 30 seconds due to sleep deprivation.?

Large scale epidemiological studies with millions of people over decades have shown that consistently getting less than 8 hours of sleep shortens your life. Sleep deprivation is linked to almost all the leading causes of death such as heart disease, cancer, diabetes, obesity and dementia just to name a few (Walker 2017).

A popular myth is that instead of 8 hours, just sleeping 5-6 hours per night can still provide all the benefits of sleep. But data suggests otherwise. Even one hour of sleep loss can be consequential. Consider the following - daylight savings time is observed in many parts of the world and after springing forward on daylight saving time and thus 1 hour less sleep, there is an increase in heart attacks and strokes by about 20% the following day. A similar rise is seen in the number of traffic accidents, providing evidence that the brain is sensitive to even small disruptions of sleep.?

Studies also show that with 4 to 6 hours of sleep instead of the recommended 8 hours, you gain weight because of a rise in hunger pangs and increased appetite. In an experiment, it was found that an individual will eat 300 more calories the next day if they had 4 hours of sleep instead of 8 hours. ?

Men who report sleeping little or having poor quality sleep have a 30% lower sperm count than their counterparts who obtain a full night’s sleep. To add insult to injury, these under-slept men also have smaller testicles compared to their well-slept counterparts.?

Studies show that there is a significant relationship between short sleep and damaged telomeres. Telomeres are regions of DNA sequence at the end of chromosomes that protect the ends from becoming frayed or tangled. Scientists believe that damaged telomeres lead to faster aging. The consequence is that less sleep can biologically age you beyond your calendar years.

A study that tracked 5000 Japanese schoolchildren discovered that those kids who were sleeping longer had better grades across the board. Smaller studies have also shown that children who consistently sleep 1 hour more compared to their peers develop higher IQ.?

If sleep is so important in our life and is as crucial as exercise and diet for good health, it's intriguing why sleep gets such little attention compared to exercise and diet.

There are a few reasons:

• Exercise and diet are the domain of the body and sleep is the domain of the brain. All research related to the brain is fairly recent, becoming possible only after MRI scans became commonplace. While a lot about sleep’s importance was said and written for hundreds of years, it was mostly anecdotal. Scientific evidence to support sleep related benefits were scant in the past due to the difficulties of designing experiments related to brain functions.?
• Effects of sleep deprivation require studies that need to be run over many years, sometimes even whole lifetimes. Long term studies are costly. For-profit pharma companies shy away from costly research if there is little possibility of profit at the end of the study.?
• Sleep is harder to commercialize and monetize. What can you sell to a person who is soundly asleep? And that’s why besides comfortable mattresses, dark curtains and calming music etc., there isn’t much that you can sell to a person who wants to benefit from the healing superpowers of sleep.?
• Popular culture equates sleep to laziness. Today's role models and influencers proudly declare that we must operate with as little sleep as possible if we want to accomplish anything worthwhile in life.

While sleep is good for us, getting it through pills or medicines is not. MRI scans show that the sleep induced by sleeping pills is different from the nourishing sleep that we get naturally. Pills also have serious side effects. For a vast majority of people, lifestyle changes are enough to ensure a good night’s sleep. National Institute of Health (nih.gov) is a great resource for?information on how to get natural 8-hours sleep. (NIH, 2011)

Moderation still applies to sleep just like everything else in life. The widely accepted optimal sleep time for adults is about eight hours and children need a little more. As an adult, if you’re sleeping more than nine hours a night and you still don’t feel refreshed, there may be some underlying medical issue.?

While modern culture treats sleep as a disposable commodity and we all have our unique life constraints, it is really up to us to understand sleep's importance and prioritize 8 hours of snooze time daily. Help is not on the way.

References*

Acute Sleep Deprivation and Risk of Motor Vehicle Crash Involvement. (2016). AAA Foundation for Traffic Safety. Retrieved February 26, 2023, from https://aaafoundation.org/acute-sleep-deprivation-risk-motor-vehicle-crash-involvement/

Milewski et al. (2014). Chronic Lack of Sleep is Associated With Increased Sports Injuries in Adolescent Athletes. Journal of Pediatric Orthopaedics, 34(2), 129-133. https://journals.lww.com/pedorthopaedics/Fulltext/2014/03000/Chronic_Lack_of_Sleep_is_Associated_With_Increased.1.aspx

NIH. (2011). Your guide to healthy sleep. https://www.nhlbi.nih.gov/files/docs/public/sleep/healthysleepfs.pdf

Pennisi, E. (2021). The simplest of slumbers. Science.org, 374(6567). https://www.science.org/doi/epdf/10.1126/science.acx9444

Walker, M. (2017). Why We Sleep: Unlocking the Power of Sleep and Dreams. Scribner.

*For brevity, I have not cited those studies where the information is considered common knowledge or is not attributed to a single study.