COMMENTARY | After a number of studies hinting at a link between sleep deprivation and weight gain, researchers have discovered the impact between sleep and genetics and the resulting effect on how much a person weighs. Sleeping longer, they believe, could suppress genetic influences on high body weight.
University of Washington Medicine Sleep Center researchers have reported the results of a federally funded study in the journal Sleep. They evaluated the relationship between length of sleep and metabolism.
The team studied 604 identical twins to discover how sleep duration might affect genetic and environmental influences on body mass. Subjects' average age was 36.6 years. Nearly two-thirds were female. Both sleep patterns and body mass index (BMI) are inherited features.
Subjects slept an average of 7.2 hours per night. Those who slept longer were slimmer than those who slept less. Subjects who got less than seven hours of sleep had an elevated genetic risk of a higher BMI than those who got more sleep.
Genetic factors were the culprit for more than a third of the weight variations in individuals who slept more than nine hours a night. With less than seven hours of shut-eye, they accounted for 70 percent of weight variations. The number dropped to 60 percent for those who slept seven to nine hours.
Scientists have long held that sleep deprivation can increase an individual's girth and cast a negative impact on health. One of the difficulties in figuring out the exact relationship is that people have significantly different individual needs as far as how much sleep is enough. A number often considered average is 7.5 hours per night. The Washington state study suggests that merely sleeping longer might suppress genetic influences on weight.
This could be good news for individuals like me who have struggled for years to keep off recently shed weight. I have a genetic propensity to being overweight and another to problems sleeping soundly.
On a typical night, I went to bed around 11 p.m. and awoke dozens of times. Sometimes the culprit was obstructive sleep apnea. Just as often, it was the cats we rescued, playing on the bed. After losing 50 pounds, I grimaced as the scale climbed five pounds within three weeks. It read four pounds more two weeks later.
Then I went on a trip and managed to slip beneath the hotel sheets by 10 p.m. each night. I slept until 7 a.m. instead of 5 a.m., when I normally fed the rescue cats. Back at home, after at least a dozen restaurant meals, I actually weighed less than before the trip. These days, I'm in bed two hours more each night in the hope that longer sleep will help suppress those genetic influences on my body weight.
Vonda J. Sines has published thousands of health and medical print and online articles. She has a special interest in sleep disorders.
- sleep deprivation