February 26, 2013
Prolonged Disruptions In Sleep Can Wreak Havoc On Your Genes
Brett Smith for redOrbit.com - Your Universe Online
Lack of sleep has long been known to have a negative impact on a person´s physiology, but a new study from researchers at the University of Surrey in the UK has found wide-ranging genetic implications that are associated with sleep deprivation.
According to the team´s report, which appeared in the journal Proceedings of the National Academy of Sciences (PNAS), the function of over 700 genes were affected by sub-standard levels of sleep.
"There was quite a dramatic change in activity in many different kinds of genes,” co-author Colin Smith, a microbiologist from the University of Surrey, told James Gallagher of the BBC. "Clearly sleep is critical to rebuilding the body and maintaining a functional state, all kinds of damage appear to occur - hinting at what may lead to ill health.”
To study the genetic effects of poor sleep, the UK researchers recruited 26 healthy volunteers — 14 men and 12 women — between 23 and 31 years old. The participants spent two separate 6-day blocks living in a laboratory setting. During one visit, they were exposed to a week of insufficient sleep, spending less than 6 hours a night in bed. In the other visit, the participants were directed to spend a week getting about 10 hours of sleep per night in bed.
At the end of each week at the sleep center, they were kept awake for between 39 to 41 hours. RNA samples were collected from the subjects during the session-ending all-nighter.
Using electroencephalography (EEG), the researchers found sleepers in the first experiment received about 5.7 hours of actual sleep, while in the second test the sleepers got about 8.5 hours of actual sleep out of their assigned 10 hours.
An RNA analysis showed the amount of sleep a participant got had a big effect on the activity of their genes.
"The tests showed that people who slept for 8.5 hours a night had around 1,855 genes whose activity rose and fell over a 24-hour cycle. But in the sleep deprived, nearly 400 of these stopped cycling completely. The remainder rose and fell in keeping with the biological clock, but over a much smaller rang," wrote the Guardian.
Some of the biggest effects of sleep loss were seen on genes that direct the body's circadian rhythms, indicating sleep loss could lead to a positive feedback loop.
"There is a feedback between what you do to your sleep and how that affects your circadian clock, and that is going to be very important in future investigations," co-author Derk-Jan Dijk, director of the University of Surrey Sleep Research Centre, told the Guardian.
The team did not investigate how long it took for genes to recover their normal levels of activity after the participants returned to normal levels of sleep. They said this would be investigated in future studies. The scientists said they were unsure if changes in gene activity are a harmless short-term response to low sleep levels, a sign of the body adapting, or are damaging to long-term health.
"If we can't actually replenish and replace new cells, then that's going to lead to degenerative diseases,” Smith concluded.