Irregular Bedtimes May Harm Your Heart Health, Study Finds

"Get a full eight hours of sleep!" is something most of us have heard a thousand times. But in recent years, research has emerged suggesting that maintaining a consistent bedtime and wake time is even more important than clocking a certain number of hours.

The study collected data from over 2,000 U.S. adults aged 45 to 84 years old. For seven days, participants wore a device that collected data about their sleep patterns and underwent a handful of cardiovascular assessments.

The researchers looked at a range of factors, including coronary artery calcium (which helps measure how much plaque buildup there is in your arteries), carotid intima-media thickness (which diagnoses the extent of the buildup), and the ankle-brachial index (a test that compares the blood pressure in the upper and lower limbs). 

The researchers cross-examined both sets of data and found that sleep irregularity—particularly when it comes to sleep duration, or how many hours of sleep you get a night—was associated with several risk factors for arteriosclerosis, a type of disease characterized by a narrowing of the arteries.

This study suggests that when it comes to sleep, maintaining a consistent bedtime and wake time is just as important as how many hours of sleep you get overall. And this isn't the first time irregular sleep habits have been connected to poor health outcomes.

A 2018 study1 showed that more irregular sleep patterns were linked to an increased risk of obesity, high blood pressure, blood sugar issues, and heart attacks. The same study showed that irregular sleepers are more likely to report chronically high stress levels and depression.

This study suggests that to promote optimal health, we shouldn't deviate our bedtime by more than two hours within a week. This gives us some wiggle room, but not much. It means that if we go to bed at 10 p.m. on the weekdays, we shouldn't stay out past midnight on the weekend, or go to bed before 8 p.m. if we're particularly tired one evening.