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| Hungry Hypothalamus
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| Studies suggest there may be a relationship between the number of hours you sleep and obesity—giving new implications to the term heavy sleeper.
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If you find yourself yawning through those early-morning meetings at the office and nodding off right after supper, you’re not alone. It’s generally acknowledged by most experts that we’re sleeping less than we did a few generations ago.
Are we getting fatter as a result?
“One could speculate that sleep deprivation is one of the leading
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causes of the obesity epidemic, since the amount of sleep we get has steadily declined over the last 30 to 50 years. One of the seminars in the national sleep meetings two years ago was entitled ‘Is sleep deprivation the cause of the obesity epidemic?’ You could correctly question whether there is a chicken/egg discussion, i.e.—are heavy people less likely to get enough sleep? I think the basic science argues in favor of the opposite, but we are still quite early in the research to say much more,” notes Dr. Philip Eichling, MPH Fellow, American Academy of Sleep Medicine, clinical associate professor of medicine, Sleep Disorders Center, University of Arizona College of Medicine and the medical director at Canyon Ranch in Tucson.
A recent long-term Columbia University study involving an estimated 18,000 participants, suggests a strong link between sleep and weight gain.
“There have been a few good epidemiologic studies in the last year showing the correlation between sleep and obesity in the population. In a study from the group at Columbia (indications are) that people who got five hours of sleep were 75 per cent more likely to be obese than the seven-hour people. There seems to be no difference between seven and eight hours however, so I often say that one should aim for seven hours as a treatment goal for weight management. There have been at least four population studies showing this correlation that I know of in the last two years,” says Dr. Eichling.
Additionally he points to “good science,” from the University of Chicago, which suggests that sleep deprivation can increase the risk for diabetes.
“Diabetes is insulin resistance, i.e., it takes more insulin to control sugar. People who are insulin-resistant are also resistant to the effects of leptin, a natural hunger-suppressing chemical. This is why diabetics tend to eat more and gain weight more easily. Thus, sleep deprivation also makes us leptin resistant and hungrier. Of course, insulin resistance is also linked to heart disease.”
Dr. Eichling started making his own connections between sleep deprivation and obesity 18 years ago when he began doing preventive cardiology and weight management at Canyon Ranch.
“I was rather quickly struck by the fact that we needed to deal with sleep issues before anyone can lose weight. This was to me a fairly obvious connection. If you are sleepy, then you are too tired to exercise and make healthy eating decisions. As I got into the study of sleep medicine I found that many of the same chemicals that are involved in sleep also control hunger. Hunger and sleep are both located in the same area of the brain (the hypothalamus). Sleep and obesity research communities, however, have not particularly spoken to each other over the years so the obvious connection had not been made until the last few years.”
Pillow Case:
There are at least five different neurochemicals involved in both hunger and sleep, according to Dr. Eichling who notes: “I could spend quite a bit of time discussing each of these chemicals but the bottom line is that when we are sleepy we get biologically hungry. It is not about psychology or eating for energy or ‘time sleeping is time away from eating’. Obviously there is a wide genetic variety and many people get less hungry when they are tired.”
- • Neuropeptide Y = Carbohydrate Hunger
- • Ghrelin = Acute Mealtime Hunger
- • Gallanin = Fat Hunger
- • Cortisol and Orexin/Hypocretin = Food-Seeking Chemical that Keeps Us Awake
Ghrelin, for example, makes you very hungry just before meals and very high levels are present in the first few hours of the night. Its purpose is to promote growth hormone and it is part of the early ‘slow wave’ deep sleep stages, which helps to explain why we suffer from the “midnight munchies,” explains Dr. Eichling.
“Almost all the diet pills (like phenteramine) are directed at suppressing neuropeptide Y. This chemical is a sedating sleep chemical. Thus the main side effect of almost all diet pills is lack of sleep. This is the reason most people had to go off of these pills e.g. they had memory problems from sleep deprivation. This will also probably be the case with the new one, ramonabont. In animals it also cuts into sleep.”
Being well rested is emerging as an important tool in the battle of the bulge.
“I counsel my patients to add at least seven hours of sleep for weight management, much as I counsel them not to eat high fat food,” advises Dr. Eichling. “It is one of the weight- management strategies.”
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