March 1, 2013 -- Sleeping fewer than six hours for several nights in a row affects hundreds of genes responsible for keeping us in good health, says a new study.
Sleep disorders are common in industrialized countries, with about 10% to 20% of the U.S. and European population reporting they often don’t get a good night’s sleep. Lack of sleep and disrupting the sleep-wake cycle are known to have a damaging effect on health, but the reasons behind this remain largely unexplored.
Laboratory Sleep Tests
The small study involved 14 healthy men and 12 healthy women who were allowed to sleep under laboratory conditions for 5.7 hours one week and 8.5 hours another week.
After each seven-day period, researchers collected and looked at blood samples that included RNA, or ribonucleic acid, from each person. The major type of RNA is called messenger RNA, and this plays a vital role in making proteins. These samples allowed the researchers to examine what happens to the RNA in the blood, brain, and liver.
Professor Derk-Jan Dijk and his colleagues found that volunteers who got less than six hours of sleep each night over the course of a week had changes to 711 RNA genes linked to inflammation, the ability to fight disease, and stress. These changes might have an impact on obesity, diabetes, heart disease, and brain function.
The findings appear in the journal PNAS.
Obesity and Diabetes
Professor Jim Horne from the Sleep Research Centre at Loughborough University says people shouldn’t be alarmed by the study results.
"The potential perils of 'sleep debt' in today’s society and the need for 'eight hours of sleep a night’ are overplayed and can cause undue concern," Horne says. "Although this important study seems to support this concern, the participants had their sleep suddenly restricted to an unusually low level, which must have been somewhat stressful."
"We must be careful not to generalize such findings to, say, habitual six-hour sleepers who are happy with their sleep,” he says. “Besides, sleep can adapt to some change, and should also be judged on its quality, not simply on its total amount."