The mismatch between the body’s internal clock and our daily schedules not only make us sleepy, but it also contributes to the growing tide of obesity, according to a large-scale study. ”We have identified a syndrome in modern society that has not been recognized until recently,” said Till Roenneberg of the University of Munich, who led the study.
“It concerns an increasing discrepancy between the daily timing of the physiological clock and the social clock. As a result of this social jetlag, people are chronically sleep-deprived,” the journal Current Biology reported. ”They are also more likely to smoke and drink more alcohol and caffeine. Now, we show that social jetlag also contributes to obesity; the plot that social jetlag is really bad for our health is thickening,” added Roenneberg, according to a university statement.
Each of us has a biological clock, he explained. We can’t set those clocks according to our whims like watches. They are rather entrained by daylight and night-darkness to provide the optimal window for sleep and waking. In modern society, we listen to those clocks “less and less due to the increasing discrepancy between what the body clock tells us and what the boss tells us.”
Roenneberg’s team is compiling a vast Utabase on human sleeping and waking behaviour, which they’ll eventually use to produce a world sleep map. Now 10 years into the effort, they already have lots of information, including participants’ height, weight, and sleep patterns.
Their analysis shows that people with more severe social jetlag are also more likely to be overweight. In other words, it appears that living “against the clock” may be a factor contributing to the epidemic of obesity, the researchers say.
“Waking up with an alarm clock is a relatively new facet of our lives,” Roenneberg says. “It simply means that we haven’t slept enough and this is the reason why we are chronically tired. Good sleep and enough sleep is not a waste of time but a guarantee for better work performance and more fun with friends and family during off-work times. And slimmer waistlines, too,” he added.