The National Sleep Foundation makes very clear sleep recommendations, depending on an individual’s age: toddlers (1-2 years) should get 11 to 14 hours of sleep each night; preschoolers (3-5 years) should get 10 to 13 hours of sleep; school-aged children (6-13), 9 to 11 hours; teens (14-17 years), 8 to 10 hours; young adults (18-25 years) and adults (24-64 years), 7 to 9 hours; and older adults (older than 65 years), 7 to 8 hours of sleep. Still, people display a need for more or less sleep…

Take my previous roommate Shelby and I, for example. Shelby insists that she only needs 6 hours of sleep: she’s constantly going to bed at midnight and waking up at around 6 a.m. Every morning, when I lived with her, I’d say: “Why were you up so early?” And every morning, she’d respond with some variation of: “My body was ready to wake up. I’m rested.” This was absurd to me because I need my 8-9 hours of sleep and I do everything in my power to ensure I get it—even if that means going to bed at 9 p.m.

So, why is it that Shelby and I (as well as many others) require different sleep durations to function properly? A new study “Selection for long and short sleep duration in Drosophila melanogaster reveals the complex genetic network underlying natural variation in sleep” explored this very question and found that the answer may lie in differences in a particular group of genes.

“This study is an important step toward solving one of the biggest mysteries in biology: the need to sleep,” leader of the study Susan Harbison, Ph.D., an investigator in the Laboratory of Systems Genetics at NHLBI, explained. “The involvement of highly diverse biological processes in sleep duration may help explain why the purpose of sleep has been so elusive.” Scientists have known and understood that genes play a major role in sleep patterns, but they’ve never been able to pinpoint exactly which genes are significant.

Hoping to add to this body of research, the researchers bred and studied 13 generations of fruit flies that were made to be either long sleepers (18 hours of sleep a day) or short sleepers (3 hours of sleep a day). Then, they compared their data between the long and short sleepers to find 126 variations among 80 genes thought to be associated with sleep duration. Additionally, they discovered that the genetic variations were linked to important developmental and cell signaling pathways. The researchers explained that the genes also play a role in brain development, learning, and memory.

Harbison explains the significance of the team’s study: “What is particularly interesting about this study is that we created long and short-sleeping flies using the genetic material present in nature, as opposed to the engineered mutations or transgenic flies that many researchers in the field are using. Until now, whether sleep at such extreme long or short duration could exist in natural populations was unknown.”

Furthermore, the research team noted that there weren’t any significant differences in lifespan among the long and short-term sleepers—which suggests that there are minimal physiological consequences (whether they be negative or positive effects) of sleeping for an extensive amount of time or little amount of time.

Previous to reading this study, I was sure that Shelby suffered from a lack of sleep. However, I now realize that she might not be lacking sleep at all. In fact, 6 hours may be plenty of sleep for her to function and even to thrive off of. I, on the other hand, without a doubt require at least 8 hours of sleep to function like a normal person the next day. And while it’d be nice to stay up an extra hour or two each night, knowing I wouldn’t suffer from any consequences, I’m also pleased to spend an extra hour or two in bed—some might even call it a blessing!

Sources:
NIH (2017, December 15). To Sleep or Not to Sleep: The Complex Genetic Network Behind Sleep Duration. NeuroscienceNews. Retrieved December 15, 2017 from http://neurosciencenews.com/genetics-sleep-duration-8193/

Harbison, S. T., Serrano Negron, Y. L., Hansen, N. F., & Lobell, A., S. (2017, December 14). Selection for long and short sleep duration in Drosophila melanogaster reveals the complex genetic network underlying natural variation in sleep. PLOS Genetics. Retrieved on December 15, 2017 from http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1007098