Short sleep duration increases expression of genetic risks for high body mass index
DARIEN, IL – Toss out another old wives’ tale: Sleeping too much does not make you fat. Quite the opposite, according to a new study examining sleep and body mass index (BMI) in twins, which found that sleeping more than nine hours a night may actually suppress genetic influences on body weight.
The study looked at 1,088 pairs of twins and found that sleeping less than seven hours a night was associated with both increased BMI and greater genetic influences on BMI. Previous research has shown that genetic influences include things like glucose metabolism, energy use, fatty acid storage and satiety. In this study, the heritability of BMI was twice as high for the short sleepers than for twins who slept longer than nine hours a night.