Quit worrying about your children’s bedtime—it is time to start worrying about your own. Adults with irregular sleep patterns may be at greater risk for obesity, depression, high blood sugar, high blood pressure, heart disease, and stroke, according to a new study in Scientific Reports. And simply going to sleep and waking up at consistent times was associated with lower risk.
Since the study reveals a correlation rather than a causation, however, the researchers cannot prove that missing bedtime triggers health issues. “We can’t conclude that sleep irregularity results in health risks, or whether health conditions affect sleep,” said coauthor on the study Jessica Lunsford-Avery of Duke University, in a statement. “Perhaps all of these things are impacting each other.”
There is a large body of research suggesting that lack of sleep causes health problems, but this is one of the first studies to demonstrate that even subtle changes in sleep patterns may spell trouble. For the study, nearly 2,000 older adults between the ages of 54 and 93, none of whom had been diagnosed with sleep disorders, were asked to keep track of their sleep schedules. They found that people with hypertension slept longer and that people with obesity stayed up later. But above all else, sticking to a regular schedule was correlated with lower health risks.
Even more interesting was that the result had nothing to do with sleep duration, per se. Even adults who got a good night’s sleep were at higher risk of disease if they did not go to bed each night and wake up each morning at roughly the same time. And this did not merely apply to those who engage in shift work, and sleep during the day—even a few minutes of difference from night to night was associated with a higher risk of cardiovascular disease.
“This finding dovetails with prior studies linking various indices of sleep irregularity–social jetlag, bedtime variability, standard deviation of bedtime, standard deviation of mid-sleep time, and standard deviation of sleep duration—to indices of cardiometabolic health,” the authors write.
This is a particularly fascinating result because it implies that sleep irregularity may be a risk factor for cardiac disease. Prior studies have even suggested a plausible mechanism by which this might work—messing with your sleep-wake cycle throws off energy metabolism, glucose metabolism, timing of food intake, and stress levels, all of which impact heart health.
“Sleep irregularity may represent a potential target for early identification of individuals at risk for cardiometabolic disease,” the authors write. “And provide opportunities for prevention and intervention efforts, and indeed, recent technological innovations may facilitate detection and treatment opportunities in the broader population.”