“How did you sleep?” You might answer that question by weighing how many hours you slept or how often you woke up throughout the night. But there is a third, often neglected, element of sleep to consider, experts say. It’s the consistency of your sleep schedule.
Sleep consistency refers to how well you maintain the same bedtime and wake-up time, give or take 30 minutes — and that includes weekends, said Jean-Philippe Chaput, a professor of medicine at the University of Ottawa.
Research suggests that most adults in the United States do not have a consistent sleep schedule. And that may be harming their health, Dr. Chaput said. Although sleep research has many limitations, scientists have found some patterns. Those who tend to deviate most from a consistent sleep schedule seem to be at higher risk of certain health conditions like cardiovascular disease, obesity, mental health issues like depression and anxiety, and dementia.
In a 2020 study, researchers analyzed the sleep patterns of nearly 2,000 adults aged 45 to 84 in the United States. They concluded that those with the most irregular sleep schedules were more than twice as likely to develop cardiovascular disease than those with more regular sleep patterns.
In another study published in 2024, researchers analyzed sleep data from more than 88,000 adults in the United Kingdom and assigned “sleep regularity” scores to all of them. Those who scored lowest, meaning they had the most irregular sleep schedules, were about 50 percent more likely to develop dementia than those who scored in the middle of the range.
Scientists aren’t sure how frequent or how severe your sleep irregularity has to be to increase your health risk, said Soomi Lee, an associate professor of sleep and aging at Penn State. But the more you deviate from your typical sleep time — whether that’s within a 24-hour period or across weeks or months — the more the risks seem to increase, she said.
In a large review of studies published in 2023, a group of sleep scientists concluded that there was enough evidence to recommend maintaining a regular sleep schedule to help protect metabolic, mental and cardiovascular health.
How to Keep Sleep Consistent
Setting an alarm to go off an hour before your bedtime every night can remind you that it’s time to start getting ready for sleep, Dr. Varga said. Doing something relaxing during that hour, such as reading or meditating, can help you wind down for bed.
It’s also important to expose yourself to sunlight every morning — ideally for 20 to 30 minutes at the same time every day, said Dr. Nishay Chitkara, the director of sleep medicine at NYC 
Health + Hospitals/Bellevue. While standing in front of a window can be beneficial, he said, it’s best to go outside to do this, even if it’s cloudy. A bright artificial indoor light, like a light therapy box, can help, too.
Light is the main cue that regulates your circadian rhythm. When it hits your eyes in the morning, your body begins its countdown to later that evening — when it releases hormones telling your body it’s time to go to bed. You may not feel exhausted from inconsistent sleep in the same way you might after a night of tossing and turning, Dr. Lee added. But try your best to stick with a sleep routine regardless. The more consistent you are, she said, the better your health will be in the long run.
Leave a Reply