It is common to be unaware of the incredible impact sleep can have on all functioning systems of the body. A rising prevalence of diabetes and obesity has been seen in the past few decades, both of which can have a devastating impact on the quality and longevity of an individual’s life. During the same period, sleep durations have also significantly decreased, signifying a direct relationship between sleep loss and impaired appetite control. This trend has stimulated research on just how much sleep can affect the hormonal systems involved with hunger.

An individual’s appetite is tightly controlled by two opposing systems of brain circuitry, appetite stimulating and appetite inhibiting, which involve several hormones:

• The hormone leptin is appetite inhibiting. It is secreted in the brain and promotes a feeling of satiety. During the early period of sleep, leptin has a circadian rhythm and its levels peak.
• Ghrelin is another essential hormone that is appetite stimulating and secreted from the stomach. Gherlin secretion increases food intake and appetite.
• Although leptin and ghrelin exert opposite effects on appetite, under normal circumstances, they are both regulated during sleep.

Several studies have been conducted to report the effect sleep deprivation has on leptin levels. One particular study that occurred in France in 1998 studied seven healthy young men’s leptin levels and subjected them to certain sleep conditions such as normal sleep and total nocturnal sleep deprivation. The evidence showed that leptin levels rise during sleep, regardless of when the sleeping occurs. This study showed a direct relationship between sleep and increases in the hormone leptin, resulting in appetite suppression.

A 2004 study at the University of Chicago in Illinois compared sleep restriction and sleep extension and the potential hormone levels of leptin that would result. For those individuals who were restricted to 4 hours of sleep for 6 days, average leptin levels were about 19% lower than those who experienced 12 hours of sleep for 6 days. Since this study did not evaluate the effect sleep has on ghrelin levels, hunger, or appetite, subsequent studies have been conducted.

Another 2004 study at the University of Chicago in Illinois studied levels of leptin, ghrelin, hunger, and appetite in individuals who either had 4-hour bedtimes or 10-hour bedtimes. Average leptin levels were 18% lower and ghrelin levels were 28% higher in the sleep-restricted condition of 4 hours compared to sleep extension, or 10-hour bedtimes. Hunger ratings were 24% higher and appetite ratings were 23% higher for those experiencing sleep restrictions, than those who had 10 hours of sleep. There was also a heightened appetite for carbohydrate rich foods, such as sweets and salty snacks, for those who had sleep restriction. These results led to the conclusion that the changes in the appetite hormones, ghrelin and leptin, are responsible for an increase in appetite and hunger. This was the first study to correlate these hormones with a magnitude of hunger change due to changing sleep conditions.

If you are currently experiencing increased appetite levels, it is important to talk to a doctor or healthcare professional. Several sleep conditions or sleep deprivation could be playing a major role in your increased appetite. Regulating your sleep patterns will allow your body to naturally balance out your hunger hormones, decreasing the risk for weight gain or diabetes.

It is apparent from the research that sleep duration has an impact on the regulation of appetite inducing or appetite suppressing hormones. It seems to alter the ability of ghrelin and leptin to appropriately signal a caloric need in the body. However, more research is needed to further examine the correlation of deprived sleep with appetite and increased hunger to arrive at a definitive answer.

References:

Simon C, Gronfier C, Schlienger JL, Brandenberger G. Circadian and Ultradian Variations of Leptin In Normal Man Under Continuous Enteral Nutrition: Relationship To Sleep and Body Temperature. J Clin Endocrinol Metab. 1998;83(6):1893-9.

Spiegel K, Tasali E, Penev P, Van Cauter E. Brief Communication: Sleep Curtailment In Healthy Young Men Is Associated With Decreased Leptin Levels, Elevated Ghrelin Levels, and Increased Hunger and Appetite. Ann Intern Med. 2004;141(11):846-50.

Spiegel K, Leproult R, L’hermite-Baleriaux M, Copinschi G, Penev PD, Van Cauter E. Leptin Levels Are Dependent On Sleep Duration: Relationships With Sympathovagl Balance, Carbohydrate Regulation, Cortisol, and Thyrotropin. J Clin Endocrinol Metab. 2004;89(11):5762-71.

Knutson KL. Impact Of Sleep and Sleep Loss On Glucose Homeostasis and Appetite Regulation. Sleep Med Clin. 2007;2(2):187-197.

Van Cauter E, Kn

utson K, Leproult R, Spiegel K. The Impact of Sleep Deprivation on Hormones and Metabolism. Medscape Neurology. 2005;7(1).

Helpful Peer-Reviewed Medical Articles:

Spiegel, K., Tasali, E., Penev, P., & Van Cauter, E. (2004). Brief communication: Sleep curtailment in healthy young men is associated with decreased leptin levels, elevated ghrelin levels, and increased hunger and appetite. Annals of internal medicine, 141(11), 846-850.

Papadimitriou, G. N., Dikeos, D. G., Daskalopoulou, E. G., & Soldatos, C. R. (2002). Co-occurrence of disturbed sleep and appetite loss differentiates between unipolar and bipolar depressive episodes. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 26(6), 1041-1045.

Pang, F. C., Chow, T. W., Cummings, J. L., Leung, V. P. Y., Chiu, H. F. K., Lam, L. C. W., ... & Fuh, J. L. (2002). Effect of neuropsychiatric symptoms of Alzheimer's disease on Chinese and American caregivers. International journal of geriatric psychiatry, 17(1), 29-34.

Taheri, S., Lin, L., Austin, D., Young, T., & Mignot, E. (2004). Short sleep duration is associated with reduced leptin, elevated ghrelin, and increased body mass index. PLoS Med, 1(3), e62.

Schmid, S. M., Hallschmid, M., JAUCH‐CHARA, K. A. M. I. L. A., Born, J. A. N., & Schultes, B. (2008). A single night of sleep deprivation increases ghrelin levels and feelings of hunger in normal‐weight healthy men. Journal of sleep research, 17(3), 331-334.

Knutson, K. L., Spiegel, K., Penev, P., & Van Cauter, E. (2007). The metabolic consequences of sleep deprivation. Sleep medicine reviews,11(3), 163-178.