Sleep Duration and Levels of Hormones That Influence Hunger

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The summary below is from the full report titled "Brief Communication: Sleep Curtailment in Healthy Young Men Is Associated with Decreased Leptin Levels, Elevated Ghrelin Levels, and Increased Hunger and Appetite." It is in the 7 December 2004 issue of Annals of Internal Medicine (volume 141, pages 846-850). The authors are K. Spiegel, E. Tasali, P. Penev, and E. Van Cauter.

What is the problem and what is known about it so far?

Hormones are substances in the body that help to regulate body processes. Over recent years, researchers have been learning a lot about the hormones that help to regulate hunger. Two of these hormones are called leptin and ghrelin. Leptin decreases hunger, so people do not feel hungry when leptin levels are high. Ghrelin increases hunger, so people feel hungry when ghrelin levels are high. Sleep plays an important role in the body's use and storage of energy from food. Researchers have found that lack of sleep leads to hunger in rodents and, possibly, hunger in humans. It is unknown whether lack of sleep influences the hormones that help to regulate hunger.

Why did the researchers do this particular study?

To determine whether lack of sleep is associated with changes in the levels of the hunger hormones leptin and ghrelin.

Who was studied?

12 young, healthy men who all had normal body size, were nonsmokers, and were receiving no medications.

How was the study done?

The researchers conducted the study in a medical center.

What did the researchers find?

After limited sleep, leptin levels decreased, ghrelin levels increased, and the men reported increased hunger, especially for foods with high carbohydrate content.

What were the limitations of the study?

The study included only 12 young, healthy men under strict research conditions. In addition, the researchers did not measure energy expenditure, so this study cannot determine whether an increase in energy expenditure might account for increased hunger after lack of sleep.

What are the implications of the study?

Lack of sleep seems to influence the levels of hunger-regulating hormones in such a way that hunger increases. It is possible that chronic lack of sleep might lead to overeating.