Sleepiness Could Be In Our Genes
New research suggests that the U.S. drowsiness may be in our genes, and may partly explain why some people seem to be able to stay fresh and alert for four hours of sleep a night.
Researchers found that after several nights of limited sleep, healthy adults who carried a particular variant of the gene DQB1 * 0602 was more sleepy and tired during the day, and had more fragmented sleep than non-carriers.
Option is closely linked to narcolepsy, sleep disorder that causes people to feel sleepy during the day. But the researchers said of the option does not mean that you develop the disorder: depending on the population of about 12 to 38 percent of the carriers is not narcolepsy, and have no problems with sleep. And although this is less common, some people may still develop frustration, even if they do not have an option.
You can read about a study led by Dr. namni Goel, associate professor of psychology in psychiatry at the University of Pennsylvania School of Medicine in Philadelphia, October 26 online issue of Neurology, the medical journal of the American Academy of Neurology (AAN).
Goel told the press that if their findings are confirmed, this may justify the recommendation of the DQB1 * 0602 carriers to take a nap or caffeine, to help them cope during sleep restriction.
For the study, researchers invited 37 healthy adult carriers of DQB1 * 0602 gene variant, and 92 healthy adults who do not have it, and watched them for a week in a sleep lab. None of the participants have any sleep disorders.
For the first two nights of the participants spent 10 hours in bed and rested.
During the next five nights, their sleep was restricted: they were "chronic partial sleep deprivation", where they were allowed only four hours in bed each night. For the rest of the lights remained, and they can read, play games or watch movies to help them stay awake.
Participants could not consume food or beverages that may affect their sleep, such as bananas, caffeine, alcohol or turkey.
For the week, the researchers measured the "quality of sleep participants, asked them to assess their sleepiness, and complete tests to assess memory, attention and ability to resist sleep during the day.
The results showed that: Recording DQB1 * 0602 was lower than the desire to sleep (sleep drive), while fully rested at night. During the second rested overnight, carriers were on average 34 minutes in stage 3 sleep, while non-carriers were on average 43 minutes. In the fifth night of limited sleep, carriers are spending an average of 29 minutes in Stage 3 sleep, compared with 35 minutes for non-carriers. Carriers of DQB1 * 0602 was sleepy and more tired than non-carriers, and their sleep was more fragmented: how, when they had a good rest and when asleep. For example: media woke up an average of four times on the fifth night of limited sleep and not wake up carriers on average only two times that night. Carriers spent less time in deep sleep than non-carriers: both during the night, rested and sleep restricted night. There was no difference between carriers and non-native DQB1 * 0602 in memory and attention performance and their ability to resist sleep during the day. The researchers concluded that the DQB1 * 0602 was associated with differences between people in a number of physiological measures of sleep, sleepiness and fatigue, but not in the cognitive measures, both during baseline (rest of nights) and chronic partial sleep deprivation.
"DQB1 * 0602 positivity in the healthy population may represent a continuum of some of the sleep-wake characteristics of narcolepsy," they wrote.
Goel said the gene variant may be a "biomarker to predict how people will react to sleep deprivation, which has significant implications for health and affects millions of people around the world."
For example, it can be very important for night shift workers, people who frequently travel across time zones, or people who spend a lot on his hands with work and family responsibilities, "said Goel, who stressed that more research should be done now to confirm the findings.
Resources from the National Space Biomedical Research Institute, National Institutes of Health, Institute of Translational Medicine and Therapeutics and the National Center for Research Resources, to help pay for research.
"DQB1 * 0602 predicts interpersonal differences in physiological sleep, sleepiness and fatigue." Namni Goel, Siobhan Banks, Emmanuel Minho, and David F. Dinges. Neurology, October 26, 2010, 75 (17): 1509-1519.