A new study by researchers at Wake Forest University School of Medicine reveals how extremes of sleep, both too much and too little, can be hazardous to your health, especially for young minority women, a group most affected by obesity and chronic metabolic disease. The findings also indicate that there’s more to “fat” than eating habits—social factors such as the need to work three jobs in a bad economy could be causing dangerous fat deposition around vital organs.
“We put a lot of stock in diet,” said Kristen G. Hairston, MD, MPH, assistant professor of endocrinology and metabolism and lead author on the study. “But this study brings up some interesting questions about the way we live. We may need to start looking at other behaviors besides daily food choices that could be contributing to the obesity epidemic in younger age groups.”
In individuals under 40, the study showed a clear association between averaging 5 hours or less of sleep each night and large increases in visceral fat, or fat around the organs. Of the study participants under 40, Hispanic men and black women were the largest groups to report getting such little sleep.
Short sleep has become more common in the United States and minorities are disproportionately affected, said Hairston, an affiliate of the Maya Angelou Center for Health Equity, part of the School of Medicine. They are also more prone to metabolic conditions, including increased rates of obesity, insulin resistance, and type 2 diabetes. The study suggests that part of the explanation for higher rates of metabolic disease in this population may lie in the association between sleep duration and fat deposition.
But sleeping the day away won’t do much to better one’s health, either. The researchers found that getting more than 8 hours of sleep on average per night has a similar—though less pronounced—effect and is a problem most commonly seen in Hispanic women of all ages.
Surprisingly, the connection between extremes of sleep and accumulation of visceral fat was seen only in patients under 40, Hairston said.
“We don’t really know yet why this wasn’t seen in participants over 40, but it was clear that, in individuals under 40, it is worse to get 5 or less hours of sleep on average each night than it is to get 8 or more hours,” Hairston said. “However, both may be detrimental and, in general, people should aim for 6 to 8 hours of sleep each night.”
The study appears in the March issue of SLEEP.