Why does lack of sleep affect us differently? Study hints it may be in our genes

Oct 25, 2010

Ever wonder why some people breeze along on four hours of sleep when others can barely function? It may be in our genes, according to new research and an accompanying editorial published in the October 26, 2010, print issue of Neurology, the medical journal of the American Academy of Neurology.

The study looked at people who have a gene variant that is closely associated with narcolepsy, a sleep disorder that causes excessive daytime sleepiness. However, having the gene variant, called DQB1 *0602, does not mean that a person will develop narcolepsy; depending on the population, 12 to 38 percent of those with the variant do not have the sleep disorder and are considered healthy sleepers. Also, people without the gene variant can develop narcolepsy, though this is less common.

For the study, 92 healthy adults without the gene variant were compared to 37 healthy adults who had the gene variant but did not have any sleep disorders. All of the participants came to a sleep laboratory. For the first two nights, they spent 10 hours in bed and were fully rested. The next five nights they underwent chronic partial sleep deprivation, also known as sleep restriction, where they were allowed four hours in bed per night. During the remaining time, lights were kept on and participants could read, play games, or watch movies to help them stay awake.

Researchers measured their sleep quality and self-rated sleepiness and tested their memory, attention and ability to resist sleep during the daytime.

The people with the DQB1*0602 gene variant were sleepier and more fatigued while both fully rested and sleep deprived. Their sleep was more fragmented. For example, those with the gene variant woke up on average almost four times during the fifth night of sleep deprivation, compared to those without the gene variant, who woke up on average twice. Those with the gene variant also had a lower sleep drive, or desire to sleep, during the fully rested nights.

Those with the also spent less time in deep sleep than those without the variant, during both the fully rested and sleep deprivation nights. During the second fully rested night, those with the variant had an average of 34 minutes in stage three sleep, compared to 43 minutes for those without the variant. During the fifth night of sleep deprivation, those with the variant spent an average of 29 minutes in stage three sleep, compared to 35 minutes for those without the variant.

The two groups performed the same on the tests of and attention. There was also no difference in their ability to resist sleep during the daytime.

"This gene may be a biomarker for predicting how people will respond to , which has significant health consequences and affects millions of people around the world. It may be particularly important to those who work on the night shift, travel frequently across multiple time zones, or just lose due to their multiple work and family obligations. However, more research and replication of our findings are needed," said lead study author Namni Goel, PhD, of the University of Pennsylvania School of Medicine in Philadelphia.

Explore further: Clot dissolver tPA's tardy twin could aid in stroke recovery

Related Stories

Clock gene sleep research has implications for workforce

Mar 09, 2007

People differ markedly in their response to sleep deprivation but biological markers of these differences have remained elusive. In findings published in this week's issue of Current Biology, researchers at the University of Sur ...

Night shift nurses more likely to have poor sleep habits

Jun 11, 2007

Nurses who work the night shift are more likely to have poor sleep habits, a practice that can increase the likelihood of committing serious errors that can put the safety of themselves as well as their patients at risk, ...

Study: Brain injuries tied to trouble sleeping

May 24, 2010

People with brain injuries may produce low amounts of melatonin, which affects their sleep, according to a study published in the May 25, 2010, print issue of Neurology, the medical journal of the American Academy of Neu ...

Recommended for you

New test to help brain injury victims recover

15 hours ago

A dynamic new assessment for helping victims of trauma to the brain, including those suffering from progressive conditions such as dementia, has been developed by a clinical neuropsychologist at the University ...

See-through sensors open new window into the brain

17 hours ago

(Medical Xpress)—Developing invisible implantable medical sensor arrays, a team of University of Wisconsin-Madison engineers has overcome a major technological hurdle in researchers' efforts to understand ...

User comments : 0