Is it bad to go to bed at a different time every night

What the guidelines say

The advice is remarkably consistent. The Centers for Disease Control and Prevention lists going to bed and getting up at the same time every day among its habits for better sleep. The American Academy of Sleep Medicine (AASM) puts keeping a consistent sleep schedule first on its Healthy Sleep Habits page and adds that you should get up at the same time every day, even on weekends or during vacations.

The NHS frames it as a routine. Its Every Mind Matters guide says that going to bed and getting up at similar times each day helps your body know when it is time to sleep, and that you should try to keep the routine the same even on days when you are not working.

The National Heart, Lung, and Blood Institute (NHLBI), part of the US National Institutes of Health, gives the most concrete number. It recommends keeping the same sleep schedule on weeknights and weekends and limiting the difference to no more than about an hour, because staying up late and sleeping in late on weekends can disrupt the body clock's sleep-wake rhythm.

What irregular sleep has been linked to

The strongest evidence so far comes from heart research. A study funded in part by the NHLBI and published in the Journal of the American College of Cardiology in March 2020 followed 1,992 adults aged 45 to 84 from the Multi-Ethnic Study of Atherosclerosis. Each wore a wrist activity monitor for seven days, including a weekend, and none had cardiovascular disease at the start. Over about five years, 111 developed cardiovascular events such as heart attack or stroke, or died from cardiovascular causes. Those with the most irregular sleep duration or timing had more than double the risk of the most regular sleepers, and the link held after adjusting for known heart risk factors, sleep apnea and average sleep length.

A 2023 study in the Journal of the American Heart Association, also partly supported by the NHLBI, looked at adults aged 58 to 78. Those whose nightly sleep varied by more than two hours within a week, such as six hours one night and eight the next, were more likely than regular sleepers to have plaque in their coronary arteries.

These are associations from observational studies, not proof that a shifting bedtime causes heart disease, and the 2020 researchers said larger and longer studies are needed. In the NHLBI's announcement, Michael Twery, director of its National Center on Sleep Disorders Research, noted that research has linked irregular sleep schedules to changes in blood sugar and inflammation.

Weekends and social jet lag

The most common kind of irregular schedule is the weekend shift. The AASM describes social jet lag as going to bed and waking up later on weekends than during the week. In a study of 984 adults aged 22 to 60, presented at the SLEEP 2017 meeting and announced by the AASM, each hour of social jet lag was associated with an 11 percent increase in the likelihood of heart disease, as well as poorer health and worse mood.

The lead author, Sierra Forbush of the University of Arizona's Sleep and Health Research Program, said the results suggest sleep regularity, beyond sleep duration alone, plays a significant role in health. The NHLBI's one-hour limit gives a practical boundary: if you get up at 6:30 on weekdays, a weekend wake-up around 7:30 stays inside it.

Fix the wake-up time first

Most of this advice anchors the morning rather than the night. In its February 2026 tips the AASM recommends waking up at the same time each day, even on weekends, and going to bed when you feel sleepy at night. The NHS page on insomnia says to wake up and get out of bed at the same time every day, and not to sleep in after a bad night but to stick to your regular sleeping hours instead.

Then set the bedtime from that anchor. The AASM suggests a bedtime early enough for at least 7 to 8 hours of sleep, and the CDC recommends 7 or more hours for adults aged 18 to 60. A 6:30 wake-up and a 10:30 bedtime, for example, leaves eight hours in bed.

A fixed bedtime is a target, not an order to lie awake. The AASM advises against going to bed unless you are sleepy, and if you do not fall asleep after 20 minutes, getting up for a quiet activity without much light, especially not electronics. Keeping the wake-up time steady on those nights is what holds the schedule together.

Common mistakes when steadying a schedule

Sleeping in to make up for a bad night. The NHS advises sticking to your regular hours instead, because a late morning pushes the next bedtime later.

Long naps. The NHLBI says that if you have trouble falling asleep at night, you should limit naps or take them earlier in the afternoon, and that adults should nap for no more than 20 minutes.

Late caffeine. According to the NHLBI, the effects of caffeine can last up to 8 hours, so a late-afternoon coffee can make a planned bedtime hard to keep.

No runway before bed. A bedtime that arrives straight from a bright screen is easy to miss. The NHLBI suggests using the hour before bed for quiet time. It also helps to have the plan written somewhere you will see it. Sleeppet keeps one bedtime and one wake time on its home screen, sends a single reminder 30 minutes before bedtime, and counts consecutive nights as a streak; it does not measure your sleep.

Shift work and other exceptions

Not everyone can keep the same hours. The NHLBI notes that shift workers may have schedules that conflict with their internal body clocks, and suggests limiting shift changes so the body clock can adjust, keeping lights bright at work, limiting caffeine to the first part of a shift, and blocking sound and light in the bedroom for daytime sleep.

This guide is general information, not medical advice. If you cannot keep a regular schedule, or sleep problems persist despite changing your habits, talk to a doctor.

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