Your Genes May Affect Your Body’s Ability to Adjust to Daylight Saving Time Changes
If you live in a country that observes daylight saving time (DST), you are probably familiar with the biannual adjustment that our body clocks must make. For some, adjusting to change is more difficult – and a recent study reveals that the amount of days required to adapt may be determined by our genetics.
Researchers discovered that early birds who typically went to bed earlier were not as negatively affected by DST as night owls who stayed up late.
The discoveries could have significant consequences for our understanding of the circadian rhythm – the natural process that tells us when to sleep and when to wake up, and which is critical for our health.
“This study is a demonstration of how much we vary in our response to even relatively minor challenges to our daily routines, like DST,” says University of Michigan neuroscientist Srijan Sen.
“Discovering the mechanisms underlying this variation can help us understand our individual strengths and vulnerabilities better.”
The researchers used genetic DNA profiling and a measure called the Objective Sleep Midpoint polygenic score to sift out the main study candidates from a sample of 831 medical school interns: the 133 individuals genetically predisposed to be early birds and the 134 individuals genetically predisposed to be night owls.
The team then employed wearables to monitor these interns’ responses during the spring DST transition in the United States (when the clocks go forward an hour). While all participants woke up at roughly the same time on weekdays, there were considerable differences in the times they went to bed and in the times they went to bed and got up on weekends.
By Tuesday, most early birds had adjusted to the new schedule following Sunday’s DST change. By the following Saturday, though, the night owls as a group were still trying to adjust to the time shift.
According to the researchers, this finding provides additional evidence that DST causes more harm than good.
“It’s already known that DST has effects on rates of heart attacks, motor vehicle accidents, and other incidents, but what we know about these impacts mostly comes from looking for associations in large data pools after the fact,” says Margit Burmeister, a neuroscientist and geneticist at the University of Michigan.
“This data from direct monitoring and genetic testing enables us to observe the effect firsthand and to distinguish between individuals who have varying circadian rhythm tendencies driven by both genes and environment. To put it simply, DST exacerbates everything for no reason.”
Additionally, the research team examined the fall DST adjustment, which occurs in the United States. There were no significant differences in how early birds and night owls adjusted in this study, indicating that our bodies adapt more easily to that particular adjustment.
While the purpose of DST is to increase daylight hours during the summer months – hence the name – its continuous adherence remains contentious. According to some specialists, the harm done to our normal circadian rhythms and the resulting impacts on our bodily and mental health exceed the practice’s possible benefits.
However, the research has far-reaching consequences beyond DST – which the team used to assess how our bodies adapt to new regulations for when to sleep and when to wake up. Future research could examine the relationship between genetics and more profound alterations in body clock rhythms.
“These genetic differences may affect how individuals adjust to jet lag or shift work as well,” the researchers say in their published report.
The study was published in the journal Scientific Reports.