Are you struggling to turn off your mind at night? Tossing and turning and calculating just how many hours of rest you can get if you can just find a way to drift off to dreamland. Are you unhappy with your weight? Trying diet after diet without seeing the results you want on the scale? According to Aaron Roberts, MD, PPG – Sleep Medicine, these two things might be more connected than you think.
We often joke around about getting enough “beauty sleep”, but did you know that the amount of sleep you get each night could be causing you to gain weight? Epidemiological studies have shown that the prevalence of obesity has roughly doubled since 1980. Coinciding with the obesity epidemic, we’ve also seen a trend of sleep less. The National Sleep Foundation recommends 7-9 hours of sleep per night for adults, and even more for children depending on their age. A whopping 40 percent of adults in the U.S. report getting less than that.
The Nurses’ Health Study followed roughly 60,000 women for 16 years, asking them about their sleep habits, weight, diet, and other aspects of their lifestyle. When the study started, the women were healthy and none were classified as obese. Sixteen years later, women who slept 5 hours or less per night had a 15 percent higher risk of becoming obese compared to women who slept 7 hours per night. Short sleepers also had 30 percent higher risk of gaining 30 pounds over the course of the study, compared to those who got 7 hours of sleep per night.
A recent article published in PLOS ONE adds to the growing body of evidence linking sleep deprivation to metabolic disorders such as obesity. In the study, 1,615 adults in the United Kingdom were surveyed regarding their sleep duration and then objective data was collected measuring different health markers including body mass index (BMI) and waist circumference. Those who slept an average of 6 hours or less per night had a waist circumference of 1.2 inches larger than those who slept an average of 9 hours. Shorter sleep was also associated with an increased BMI and lower levels of the good cholesterol, HDL.
When you are sleep deprived, your body produces more ghrelin (hunger hormone) and less leptin and peptide YY (satiety hormones). This equals weight gain. Your body also ramps up production of a lipid known as endocannabinoid, which elicits a response in your brain similar to how marijuana causes “the munchies”. Furthermore, research shows "impulse control” and the ability to practice “delayed gratification” are lowered with sleep deprivation, making people susceptible to poor food choices.
Surprisingly, the recent study in PLOS ONE did not find a link between obtaining less sleep and eating a poor-quality diet. Past studies have proposed that lack of sleep can cause individuals to crave fatty foods with high-sugar content in addition to providing more opportunity to eat food. These new findings place even more of an emphasis on the relationship between sleep deprivation and negative alterations in metabolism. The researchers think a lack of sleep lowers your basal metabolic rate (BMR). As you gain more fat and lose muscle, your BMR lowers even more creating a vicious cycle.
There are a few caveats to keep in mind about the study. It relied on self-reporting instead of a more objective measure of sleep quantity such as actigraphy, and numbers were reported as averages rather than specific amounts. It also did not follow participants over time and should be viewed as a snapshot in time. Lastly, correlation does not imply causation, but when the results are taken into account with all the previous studies the scale tips in favor for sleep deprivation being linked with obesity.
People who sleep less than the recommended amount per night tend to weigh more and have bigger waistlines. Luckily, obtaining more sleep is a modifiable behavior, but it starts with practicing good sleep habits. If you think you might have a sleep disorder such as obstructive sleep apnea causing you to get less than the recommended amount, then you should schedule an appointment with your primary care physician for further evaluation. Diet and exercise may be the cornerstones of weight management, but ironically one of the most important factors protecting you from weight gain might also be the most sedentary activity – sleep.