Sleep More And Weigh Less?

April 8, 2008

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By one of those stranger than fiction coincidences when I woke to my radio alarm clock this morning the feature was on sleep and weight. “Sleep more and weigh less”, filtered into my brain. I thought did I really hear that right? Surely you need to be up and doing stuff to lose weight.

As I fully focused on the radio, I heard somebody repeat it, and say that it does sound counterintuitive. So I decided to take a look at the topic of sleep and weight.

This is what I found out. Those that slept less than 8 hours in duration had on average increases in BMI (body mass index) proportional to amount of sleeping they were missing.

Recently studies in humans have demonstrated that sleep restriction or deprivation results in a “dysregulation” of appetite control and increased hunger. In other words, those that were sleep restricted had bigger appetites, were hungrier and ate more. Further, there were changes in glucose tolerance so the sleep restriction was bad for diabetics.

Why should this be? Sleep regulates a number of hormones. Included in these hormones are leptin and ghrelin, both of which are involved in appetite. Leptin is also involved in control of energy expenditure. Sleep restriction decreases leptin levels, which causes an increase in appetite and a decrease in energy expenditure (metabolic levels). Sleep shortage increases levels of ghrelin which results in both more food intake and fat deposition. The changes in both these hormones will have a negative impact on food consumed and fat accumulation.

So control of appetite and an increased metabolic rate are two more very good reasons to get a good amount of sleep every night.

Abstract for a review article about sleep and body function.
photo credit: CraigGrocott