Here’s some really pleasant news for those fond of sleeping. Research from University of Washington suggests that people who sleep more are less likely to put on weight, as genetic factors that influence obesity are suppressed with longer hours of snooze time. (1)
The study which was conducted on 1088 pairs of twins found that those sleeping for fewer than seven hours in the 24-hour cycle were more likely to have higher body mass index (BMI) coupled with greater genetic influence over higher BMI.
Body mass index, though a rough-and-ready measure, is a key index that relates your weight to your height. A woman is considered overweight if she has a BMI ofmore than 25 and obese of she has a BMI index of more than 30. (2)
Earlier research had shown that genetic influences such as glucose metabolism, energy use, fatty acid storage and satiety affect weight gain. But this was the first study that exhibited genetic heritability of BMI as an influential factor.
In fact, it was found that the heritability of BMI was twice as high for the short sleepers than for twins who slept longer than nine hours a night.
According to Nathaniel Watson, MD, MSc, the lead researcher and author of the study, “The results suggest that shorter sleep provides a more permissive environment for the expression of obesity related genes. Or it may be that extended sleep is protective by suppressing expression of obesity genes.” (3)
Here are some interesting findings of the study expressed in numbers: (Study Summary)
• Twins who slept an average of less than seven hours a day showed:
o 70 percent genetic influence in the differences in BMI
o 4 percent of the BMI variation was due to common environment
o 26 percent was attributable to unique environment
• Twins who averaged more than nine hours of sleep a day showed:
o 32 percent genetic influence on BMI variations
o Common environment accounted for 51 percent of the difference in weight gain
o Unique environment contributed 17 percent to weight variations
It was agreed that more research needs to be done covering various age groups, ethnicities etc to corroborate the conclusions of this study.