Your Chaotic Sleep Schedule Might Be Hurting Your Heart

When it comes to getting a healthy night’s sleep, it’s not just the hours that matter. New research released this week suggests that having a chaotic, inconsistent sleep pattern can raise your risk of cardiovascular problems.

Scientists studied the sleep activity patterns of residents living in the UK, focusing on people’s tendency to sleep and wake up around the same time each day. Those who consistently went to bed and woke up at a regular time were less likely to experience strokes, heart attacks, and other cardiovascular issues than so-called irregular sleepers over a long follow-up period, the researchers found. Importantly, this added risk was seen even in irregular sleepers who got lots of bedtime, indicating that sleep regularity itself is a crucial aspect of maintaining good health.

Plenty of research has found that getting an adequate amount of sleep (about 7 to 9 hours a night) is important for both our long-term physical and mental health. But more recent research has started to show that the timing of our sleep and wake cycle can also affect us down the road. Much of the current evidence on the topic has been limited to cross-sectional studies, however, which only look at people at a specific time and place. In this new study, the researchers were instead able to analyze data from the UK Biobank, a longstanding research project that has proactively followed residents’ health for many years. They specifically studied volunteers who were given devices to wear on their waist that objectively tracked their sleep activity for a week.

Using this data, they studied the health of over 70,000 people who had no preexisting cardiovascular disease at the start of the study. They found that irregular sleepers and moderately irregular sleepers were significantly more likely to develop major adverse cardiovascular events over an eight-year follow up period than those who regularly slept and woke up at the same time. After accounting for various factors, irregular sleepers were 26% more likely to experience cardiovascular problems than regular sleepers. The team’s findings were published Friday in the Journal of Epidemiology and Community Health.

“No one is perfect across a whole year, and if you don’t have a regular sleep pattern for one or two days a week, it’s not going to kill you. But if you repeatedly have irregular sleep, five or six days a week, then it becomes chronic, and that is a problem,” lead researcher Jean-Philippe Chaput, a pediatrician and sleep researcher at the University of Ottawa in Canada, told the Guardian. According to Chaput, regular sleep can be defined as sleeping and waking up at least within a hour of the same time each night, though the more consistent the better.

Getting enough sleep is still important, but it doesn’t seem to entirely offset the potential harms of irregular sleep. When the researchers accounted for sleep duration in their study, they no longer saw an increased risk in moderately irregular sleepers (meaning that when these people got enough sleep, they were no worse off), but the same wasn’t true for consistently irregular sleepers. It’s even possible that sleep regularity is more influential than sleep duration on our heart health, though more research will have to be done to know for sure.

While getting regular sleep in general is vital to our health, the researchers say that waking up at the same time should be a bigger priority, even for people trying to pay back their sleep debt during weekends.

“Waking up at different times each morning really messes with your internal clock, and that can have adverse health consequences,” Chaput said. “If you need to catch up on sleep you’ve missed during the week at weekends, then going to bed earlier is better than lying in—you should still be trying to wake up at the same time, even on Saturdays and Sundays.”

For people interested in a natural remedy for their sleep irregularity, I might recommend adopting a cat—a living, meowing alarm clock that will never let you forget exactly when their breakfast time arrives.