It’s not just how much sleep you get – keeping a regular schedule matters, too. In fact, a growing body of research shows that the consistency of your sleep schedule may be even more important than the amount of sleep you get each night.
If you’ve gotten into the habit of skimping on sleep during the week and catching up on the weekends, taking steps to narrow that sleep gap can have both short- and long-term benefits, including everything from reducing social jetlag to lowering the risk of premature death.
The effects of inconsistent sleep
While adults should obtain seven to nine hours of sleep each night, most of us fall short: A recent report published in JAMA Network Open found that close to three-fourths of US adults get less than seven hours of sleep on workdays. Not surprisingly, the same report found that adults went to sleep later and woke later on non-workdays, gaining about 25 more minutes of sleep.
In its consensus statement on sleep regularity, released in late 2023, the National Sleep Foundation affirmed that maintaining a regular sleep schedule is important for health and performance but also emphasized that making up for lost sleep is still important for overall health.
Here are some of the impacts of inconsistent sleep:
Social jetlag
As a result of the timing difference between weeknights and weekend nights, nearly half of the adults in the study experienced at least one hour of social jetlag, measured by comparing the midpoint of their sleep on workdays and non-workdays.
The effects of social jetlag are similar to what happens when we travel from one time zone to another (aka jet lag): Our bodies and our internal sleep schedules end up out of sync with external demands such as our required wake time on workdays and the time we need to (or should) be going to bed. This can make it hard to fall asleep when bedtime rolls around, increasing the likelihood of not feeling rested when the alarm clock rings the next morning.
Gut health
The long-term effects of sleep inconsistency are also considerable, given that irregular sleep disrupts circadian rhythms. One new study looked at several aspects of sleep and whether they affected gut microbiome diversity, which has wide-ranging importance for health. Overall, variability in nightly sleep had the biggest impact, even more so than the amount of sleep participants got, the amount of time it took them to fall asleep, and even how much time they spent awake during the middle of the night. The takeaway? Sleep consistency may be a key indicator of future gut health.
Body mass index
Sleep plays an important role in regulating leptin and ghrelin, the two hormones that control feelings of hunger. Previous studies have found that inadequate sleep increases our penchant for higher fat or sugary foods and contributes to obesity risk. But sleep consistency matters too: One study published in JAMA Internal Medicine found that participants whose body mass index was over 30 (considered the threshold for obesity) slept somewhat less than their counterparts (about 15 minutes less) but were also likely to have more variable sleep.
Other metabolic abnormalities
Irregular sleep has been shown to contribute to metabolic dysfunction, which includes abdominal obesity as well as other metabolic disorders, including hypertension and high blood sugar, and increases the risk for diabetes, stroke, and other diseases.
Heart health
Obtaining consistent sleep may also help protect against cardiovascular disease. One recent study found that the likelihood of developing calcified plaque in coronary arteries — considered a precursor to heart attacks and strokes — was higher in participants whose sleep was inconsistent over the course of a week (defined as having nightly sleep totals that varied by at least two hours).
Mortality risk
As if all of that weren’t enough, a study published last month in Sleep, which included more than 60,000 participants, found that keeping a regular schedule was associated with a lower risk of premature death. The researchers concluded that having a more stable sleep-wake pattern mattered even more than sleep duration as a predictor of mortality risk overall. (The only exception was for deaths from cardiometabolic disease, where both sleep duration and sleep consistency were independent predictors of risk.)
How to narrow the sleep gap
If your sleep could use a consistency tune-up, there are several strategies that may help.
Watch out for weekend oversleeping
If you’re waking earlier during the week than you’d like to due to work or other responsibilities, the tendency is to sleep later on the weekends so you can catch up. That’s still a recommended strategy per the National Sleep Foundation’s recent consensus statement: It’s better to recoup that lost sleep than be sleep-deprived.
Keep in mind, however, that sleeping more than an additional hour or two can exacerbate social jetlag. “You want to catch up on your sleep and repay that sleep debt you’ve created,” says Dr. Seema Khosla, medical director of the North Dakota Center for Sleep in Fargo. “But you don’t want to create another issue of being so sleep-satiated when you sleep late on Sunday that you can’t fall asleep at the right time on Sunday night.”
Be aware, too, that if you’re regularly not clocking enough hours, weekend recovery sleep may not be enough to erase the shortfall you’ve accumulated over the course of the week. The physiologic effects aren’t fully reversed either: One recent study found that even after two nights of catch-up sleep, participants’ heart rate and blood pressure were still higher than their baseline (pre-sleep-loss) levels.
Reverse-engineer bedtime
Instead of trying to make up for lost sleep on weekends, concentrate on getting more sleep during the week. “Start with what time you want to wake up,” says Khosla, “then backtrack seven to nine hours, or whatever your number is, and that’s bedtime.” Try making the change in 15-minute nightly increments as you work toward this. And be sure to carve out some downtime for yourself, she adds, and allow enough time for other evening activities — everything from exercise to walking the dog.
Successfully changing your bedtime can be difficult, Khosla points out, “unless you really are thoughtful about what actually has to happen from the time you get home until the time you go to bed.”
Banish bedtime procrastination
If you’re regularly postponing sleep so you can watch TV or scroll on your phone, you may be engaging in what’s known as revenge procrastination. When it comes to bedtime, “we don’t always listen to the cues our body is trying to give us,” Khosla notes.
Not surprisingly, delaying bedtime to eke out a bit more “me time” affects sleep: One recent study found that this “thief of bedtime” resulted in later bedtimes and less overall sleep.
Bank your sleep ahead of time
If an all-nighter or other sleep-loss scenario is on the horizon, consider getting some extra sleep ahead of time to help cushion the shortfall. This method of banking your sleep can make you more resilient in coping with the effects of sleep loss and also help you bounce back more quickly. The idea, Khosla explains, is to make sure you’re “sleep-satiated” ahead of time; starting off with any sort of deficit makes subsequent sleep loss that much more difficult. Taking a nap is another option that can help.
Minimize jet lag
The rule of thumb for recovering from jet lag is one day for every time zone crossed. Here, too, planning ahead can help: Khosla recommends that travelers gradually change rise time and bedtime prior to leaving and then prior to returning.
Make incremental improvements
Aim for a consistent sleep schedule, but know that it’s not always going to be perfect. “Life happens – your sleep may not always be consistent,” Khosla points out.
“I think we also have to extend kindness to ourselves and grace. We don’t always sleep great every single night, and that’s probably not our goal. I think our goal is to get us better than where we are now.”
