Short sleepers hungrier, more susceptible to obesity: study

People who sleep fewer hours are more at risk of becoming obese because they have stronger feelings of hunger, Japanese researchers said.

The scientists from Kao Corp. and Waseda University discovered that appetite-regulating hormones decline among people who sleep less.

“The findings made clear that people who continue to sleep only for short periods of time will have a stronger appetite, although their energy consumption will not change. That leads to obesity,” said Sunao Uchida, a sleep science professor at the university’s Faculty of Sport Sciences.

Uchida, Masanobu Hibi, a senior researcher at Kao Health Care Food Research Laboratories, and other scientists surveyed nine healthy men with an average age of 23.2 years.

The subjects had their metabolic rates measured under two different conditions--after they took 7-hour sleep for three consecutive nights and after they slept for three-and-a-half hours daily for another three days.

The research team put the subjects in a chamber designed to accurately measure their metabolic rates.The study found that the blood levels of appetite-regulating hormones among the subjects had decreased by more than 10 percent after they slept three-and-a-half hours compared with figures after they had seven-hour sleeps.

Their hormone quantity recovered to nearly the same level after they slept for seven hours on the day after the three-day period of short sleeping.

The scientists also asked the subjects about their hunger sensations every hour. Although they ate the same amount of food during the two sessions, they had stronger feelings of hunger when they slept fewer hours.

The difference in hunger levels between the two situations widened just before they went to bed, according to the researchers.

Under the short-sleep condition, they consumed a larger amount of energy at night because they stayed up later. But the daily energy consumption levels were roughly the same under the two conditions.

“The future challenge is to closely survey correlations between food consumption, sleep time and physical activeness,” Uchida said.

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