Sleep your way thin?
Yes my friends, I’m afraid it’s true… lack of sleep can pack on the pounds! In 2004 a couple of researchers were analyzing the NHANES database, and noticed that sleep deprivation was an independent risk factor for obesity. Since that observation, more studies have confirmed that sleep debt is associated with weight gain. It’s not completely clear how this works – but one writer summarizes:
“Sleep causes changes in the brain, leading to abnormal secretion of hormones which can result in several body disturbances that include excessive daytime sleepiness, mood changes such as depression or anxiety, altered hunger and eating patterns, and ultimately further sleep disturbances. It’s a vicious cycle!… Throw out the diet bars, and fluff up the pillows.”
I bet my sleep expert colleague, Dr. Steve Poceta, has some further thoughts on this. Let’s ask him!
This post originally appeared on Dr. Val’s blog at RevolutionHealth.com.
You are so right—almost all studies suggest a relationship between less sleep time and increased weight. Most of these studies look at large numbers of people and make correlations between reported sleep times and weight or obesity. Some of these studies from the mid-western US have confounding factors such as socio-economic status, which at the low end is itself a predictor of obesity. Think of the single mom working 1 or 2 jobs and eating fast food every night, sleeping form midnight to 5 am. Also, think of the busy office worker who is yawning after lunch—what does he or she do? Go get a candy bar, walk around, and wake up. In almost every real life example, it seems that sleepiness, sleep deprivation, and eating go hand in hand. It is also probably true that narcoleptic patients (who are very sleepy) are also overweight. However, there are also very active, energetic, less-sleep types who are thin, so the connection is not 100 %.
In the brain, the regulation of appetite is in the hypothalamus. It turns out that a basic sleep chemical is also in the hypothalamus along with a variety of other functions. Hyopcretin deficiency is the accepted caused of narcolepsy, either because of a receptor defect or damage to the nerve cells that produce hypocretin in the hypothalamus. The other name for hypocretin was “orexin”, a word coined by some of the scientists who discovered this neuropeptide which seems to affect appetite. So, appetite and sleep are linked at the hip via this pathway, although the whole story is not figured out, and my version is over simplified. Leptin levels may also affect this relationship.
In many cases of science, it is hard to determine cause and effect. Will sleeping more and being less sleepy in the day help you lose weight? I think so, but the studies have not been done. Will dieting and losing weight help you sleep more? Again, we don’t know for sure.
But the observation is there: Overweight people tend to sleep less / people who tend to sleep less are more likely to be overweight. Now we need intervention studies to understand cause and effect.
For most of us fairly normal people however, the course is clear: Sleep enough to feel rested the next day—about 7 to 8 hours. Keep you weight down so that your body mass index is under 25. You’ll be on the cutting edge of health trends.
By the way, I forgot to mention that there are studies in rats proving that sleep deprivation causes weight gain. I won’t tell you how, but rats can be totally deprived of sleep. After several days their metabolism slows, they gain weight, eat more, get sick in various ways, and die. This type of sleep deprivation does not occur in “normal sleep disorders” even if they are severe.