Studies On Sleep & Weight Loss In Women

Several studies over the years have shown a correlation between insufficient sleep and weight gain, but only a few have focused specifically on women. Initially, it was unclear which came first -- the weight gain or the sleep deficiency -- and what caused the link. Researchers at the University of Chicago have now identified the role that two new hormones play in appetite and how sleep affects them.

University of Chicago

A study performed at the University of Chicago Huron Center initially showed that women who got fewer than five hours of sleep per night were more inclined to gain weight than those who regularly got seven hours of sleep, but it was unclear why. A follow-up study published in the "Annals of Internal Medicine" in December 2004 showed that sleep deprivation can increase the body's production of the newly discovered hormone ghrelin up to 28 percent. Ghrelin triggers hunger. Simultaneously, the sleep-deprived subjects also recorded lowered levels of the hormone leptin, which signals the body is full and should stop eating. The second study, however, focused on men, and the researchers concluded that more research is needed to determine if hormonal reaction to sleep loss is the same in women.

Case Western Reserve University

Case Western Reserve University in Cleveland, Ohio, performed a much more sweeping study of 68,183 subjects, all women, over a 16-year period. This study also found a correlation between lack of sleep and weight gain. The results, presented at the American Thoracic Society's International Conference in 2006, determined that women who slept five hours per night or less gained 2.3 more lbs. than those who got adequate sleep. Women who got six hours of sleep per night gained an average of 1.5 lbs. Serious weight gain of more than 30 lbs. was most frequently reported in the women who slept fewer than five hours per night.

University of Helsinki

Researchers at the University of Helsinki reported in the "International Journal of Obesity" in 2010 that among its study group of 7,400 adults, all older than 40 years of age, women who reported sleep problems gained more weight over a period of seven years than those who did not. Unlike the findings of the University of Chicago study, the University of Helsinki determined no link between sleep and weight gain among the male subjects. However, researchers noted that only 1,300 of the people studied were women, which may have skewed the gender determinations.

Kaiser Permanente

Kaiser Permanente and Harvard Medical School researchers performed a study focusing specifically on new mothers. A year after giving birth, those who slept five hours a day were three times more likely to have retained their pregnancy weight than mothers who got adequate sleep. Those who slept six, seven or eight hours a day did not retain the weight. The researchers reported their study in the "American Journal of Epidemiology" in November 2007.