Oct. 25, 2010 -- A genetic difference may make some people more likely to suffer the ill effects of sleep deprivation.
Researchers have found that people with a certain gene were more likely to feel sleepy or fatigued but have difficulty sleeping after only four hours of sleep, compared to people without the gene.
“This gene may be a biomarker for predicting how people will respond to sleep deprivation, which has significant health consequences and affects millions of people around the world," researcher Namni Goel, PhD, of the University of Pennsylvania School of Medicine in Philadelphia, writes in a news release. "It may be particularly important to those who work on the night shift, travel frequently across multiple time zones, or just lose sleep due to their multiple work and family obligations."
The gene, DQB1*0602, is closely related to the sleeping disorder narcolepsy, which causes excessive daytime sleepiness. Between 62% and 88% of people with the gene have the sleep disorder.
Gene Affects Sleep
In the study, published in Neurology, researchers compared the effects of sleep deprivation in 92 healthy adults without the genetic variant and 37 healthy adults with the gene but who did not have any sleep disorders.
All of the participants came to a sleep laboratory, and for the first two nights spent 10 hours in bed and were fully rested. For the next five nights, they underwent sleep deprivation and were allowed only four hours in bed per night.
Researchers found that people with the gene were sleepier and more fatigued when fully rested and when sleep deprived, and their sleep was more fragmented.
For example, people with the gene woke up an average of almost four times a night during the last night of sleep deprivation, while people without the gene woke only twice. In addition, people with the gene spent less time in deep sleep than people without the gene.
However, the two groups performed the same on tests of memory and attention, and there was no difference in their ability to resist sleep during the day.