Poor Sleep May Be Linked to Your Genes
Poor sleeper? Blame it on your genes, a new study suggests.
"Sleep patterns are influenced by genetic differences," said study co-author Dr. Daniel Gottlieb, a sleep researcher and associate professor of medicine at Harvard Medical School. "This study is one of the first to begin identifying these genetic differences, and will hopefully help us better understand the causes of sleep disorders and their relation to other important diseases."
The findings suggest that certain genetic variations may make a difference of only a few minutes’ sleep each night. But the research may eventually lead to a wider picture of how genes affect conditions such as attention deficit hyperactivity disorder (ADHD) and diabetes, said Gottleib. Sleep duration is also connected to conditions including diabetes, high blood pressure and depression.
It's possible that a gene variation causes sleep problems, which then cause, say, high blood pressure, Gottlieb said. But it's also possible that the gene itself directly affects both, since "most genes serve multiple functions," he added.
In the new study, researchers examined the genes and sleep habits of 51,951 Americans. They found two genes linked to sleep duration, one of which was linked to about three minutes of extra sleep per night. Then they reviewed previous studies for more information about those genetic variations. Those with the gene variations not only slept longer but also had lower levels of ADHD and lower blood sugar, the study found.
The other DNA area identified - this one linked to shorter sleep - has previously been associated with psychiatric problems, including risk for depression and schizophrenia, the researchers said.
Jim Horne, of the Sleep Research Center at Loughborough University in England, cautioned against making too much out of the study's findings. "The effect of these genes on sleep is tiny, accounting for no more than a few minutes of a total night's sleep," he said. “There are numerous mechanisms, maybe hundreds, in the brain affecting our sleep one way or another, all of which will be coded by one or more genes. Those looked at here are just a very few," Horne said.
Horne also noted that the study only looked at a rough measure of time spent sleeping, not whether it was high quality sleep. In addition, he said, there are far more powerful non-genetic influences on out sleep.
For now, the research won't have any immediate impact on the prevention, diagnosis or treatment of sleep disorders, Gottlieb said. But "a long-term goal of this research is improved understanding of sleep disorders, including early identification of those at risk for sleep disorders in order to prevent their occurrence," he said.