As adults, most of us are familiar with the immediate effects of sleep deprivation – be it due to work requirements or hours of late night binge watching – including fatigue, slower reaction times and in more severe cases, reduction of cognitive ability to a state comparable with intoxication. We are also generally aware of some of the deeper consequences of sleep deprivation, such as a compromised immune system, and an increase in the risk of cardiovascular issues in the long run. But could sleep deprivation be directly linked to the increase in global obesity levels? If so, how are sleep and body weight connected? And could too much sleep have the same effects on our weight as too little sleep?
To begin with, there does appear to be a strong connection between sleep and the risk of obesity. Studies have been conducted around the world on as many as 68,000 people in one test, which spanned over the course of more than a decade, and the results, although observational, paint a pretty clear picture. To put it briefly, chances of obesity in children who did not get enough sleep was 89%, and 55% in adults who experienced chronic sleep deprivation.
Rather than sleep deprivation itself, it is the consequent changes within our body that result in a much higher tendency to gain weight. Sleep deprivation can alter the hormones in our body that control hunger, increasing our appetite as well as our satiation point (we don’t feel full as easily). By not getting enough sleep, we make ourselves prone to more hunger, and with an increased amount of wakeful hours that accompany sleep deprivation, it becomes all the more easier to eat more and more.
Sleep deprivation also lowers our metabolism rate. In a study conducted on fifteen men, a mere six nights of sleep deprivation were enough to lower their metabolism by 20% (they were allowed four hours of sleep on each of those six nights). A lower metabolism leads to increased chances of weight gain. Moreover, the fatigue that follows sleep deprivation means we probably won’t be as physically active during the day as we would have been with enough sleep (and this doesn’t do us any favours in the weight management department).
There is also a tendency towards craving foods with a higher content of fat and carbohydrates when we are sleep deprived, and this could be linked to insulin resistance, which can develop in our cells if we don’t get enough sleep.
Insulin is a hormone that regulates the amount of sugar (glucose) in our blood, playing a pivotal role in making sure that our blood doesn’t have too little or too much sugar, and that enough sugar is transported to our cells to be used as energy. When cells become insulin resistant, this results in an excess of sugar in the blood, which in turn triggers the body to produce more insulin. If you don’t get enough sleep for six consecutive nights, your body’s ability to lower blood sugar levels decreases by 40%.
This increased level of insulin is what makes you hungrier, and your body tells you to store more calories (because your cells are deprived of sugar). This rather dangerous cycle could spiral into a rapid increase in weight gain leading to diabetes, all because we didn’t get enough sleep.
The good news is that the effects of sleep debt can be reduced over time, if we make sure to get at least seven hours of sleep every night. On the other hand, too much sleep could also be linked to obesity. However, studies reveal that this might be a result of reverse causation, in that people already had obesity-related conditions (sleep apnoea, obstructive lung disease, depression, etc.) which then triggered excessive sleep, as opposed to the other way around.
At the end of the day, even though a few sleep-deprived nights won’t do any lasting damage, continuing this practice in the long term can lead to some rather disastrous effects. A minimum of seven hours of sleep is what most adults need in order to keep the body functioning at its best. It is important to note that if you have been sleeping for less than seven hours regularly over a long period of time, you might feel like you have adjusted to it because you don’t experience any of the symptoms of sleep deprivation. However, you should know that those negative effects are still happening; what changes is your body’s perception of tiredness, which evens out with chronic sleep deprivation.
When it comes to a good night’s rest, balance and routine are important. Try to go to sleep and wake up at the same time every day. In addition to getting the recommended seven hours of sleep, make sure the quality of your sleep is good as well, as this is just as important as how many hours of sleep you have. Sleep is crucial for repairing and maintaining our body, and getting enough of it will do us wonders in the long run.
ASAP Science. “How Much Sleep Do You Actually Need?” YouTube. July 27th, 2014. Web. <https://www.youtube.com/watch?v=SVQlcxiQlzI> as seen on July 26th, 2020.
Pullen, Caroline. “7 Ways Sleep Can Help You Lose Weight” Healthline. June 6th, 2017. Web. <https://www.healthline.com/nutrition/sleep-and-weight-loss#section> as seen on July 26th, 2020.
“Waking Up to Sleep’s Role in Weight Control”. Harvard School of Public Health. Web.<https://www.hsph.harvard.edu/obesity-prevention-source/obesity-causes/sleep-and-obesity/ > as seen on July 26th, 2020.