Need to catch up on sleep? Don’t plan to do it on Sunday night. Compared to other nights of the week, people have the most difficulty falling asleep on Sundays, according to new findings from the market research company Toluna Omnibus.

In the survey, more than 3,000 adults across the country weighed in on how long it takes them to fall asleep each evening. The results: Two out of five people said they have the most trouble drifting off on Sunday nights. Among them, 70 percent said they toss and turn up to 30 minutes longer on Sundays. What’s more, of the people who didn’t report having trouble falling asleep on Sunday nights, a quarter said they still worry they will have difficulty.

So what makes it so hard to get rest on the night when you really need it to start your workweek on the right note? Study author Michael Breus, PhD, a sleep expert and a clinical psychologist, says the answer is two-fold: First, you tend to change your typical routine on weekends. And when you hit the sack after midnight on Friday and Saturday, your body isn’t quite ready for bed when you try to tuck in earlier on Sunday.

Stress is another big reason you might struggle to snooze on Sundays. When your Monday-morning to-do list is top of mind, it can be tough to relax and drift off to sleep.

While Breus says sleep is important every night of the week to support your health and productivity, getting seven to nine hours of sleep on Sunday nights is absolutely vital—it helps you fully recharge and establish a sound sleep schedule for the workweek to come.

Need help sleeping soundly on Sundays (or any night, for that matter)? Follow these tips to get the shuteye you need.