Sleep isn’t just a lackadaisical way to spend your weekend morning time, it’s an essential biological function that is associated with good health, when appropriately obtained or disease, when deficient. Surprisingly, while we spend roughly one-third of our lives sleeping, our understanding of how this biological process is regulated is poorly understood. Yet, in this technological age of wearable electronic devices, new information can be gathered about this enigmatic process, which is exactly what an international team of investigators led by scientists at the University of Exeter set out to uncover.
Amazingly, the researchers found 47 links between our genetic code and the quality, quantity, and timing of how we sleep. Moreover, they include ten new genetic links with sleep duration and 26 with sleep quality. Findings from this study were released today in Nature Communications through an article entitled “Genetic studies of accelerometer-based sleep measures yield new insights into human sleep behavior.”
“We know that getting enough sleep improves our health and wellbeing, yet we still know relatively little about the mechanisms in our bodies that influence how we sleep,” explains lead study investigator Andrew Wood, PhD, a lecturer at the University of Exeter. “Changes in sleep quality, quantity and timing are strongly associated with several human diseases such as diabetes and obesity, as well as psychiatric disorders.”
This new genome-wide association study (GWAS) was funded by the Medical Research Council and reviewed data from 85,670 participants of UK Biobank and 5,819 individuals from three other studies, who wore accelerometers—wrist-worn devices (similar to a Fitbit) which record activity levels continuously. They wore the accelerometers continuously for seven days, giving more detailed sleep data than previous studies, which have relied on people accurately reporting their own sleep habits.
Among the genomic regions uncovered is a gene called PDE11A. The research team discovered that an uncommon variant of this gene affects not only how long you sleep but your quality of sleep too. The gene has previously been identified as a possible drug target for the treatment of people with neuropsychiatric disorders associated with mood stability and social behaviors.
Additionally, results from the study showed that among people with the same hip circumference, a higher waist circumference resulted in less time sleeping, although the effect was very small—around 4 seconds less sleep per 1 cm waist increase in someone with the average hip circumference of around 100 cm.
Lastly, the researchers found that collectively, the genetic regions linked to sleep quality are also linked to the production of serotonin—a neurotransmitter associated with feelings of happiness and wellbeing. Serotonin is known to play a key role in sleep cycles and is theorized to help promote deeper and more restful sleep.
“This study identifies genetic variants influencing sleep traits and will provide new insights into the molecular role of sleep in humans,” concludes lead study investigator Samuel Jones, PhD, of the University of Exeter Medical School. “It is part of an emerging body of work which could one day inform the development of new treatments to improve our sleep and our overall health.”