When Monday morning rolls around are you ready to hit the ground running or would you rather turn over in bed and fall back asleep?

Yep, we thought so. But turns out it’s less a uniquely torturous aspect of Mondays causing that fatigue and more likely because we have the most difficulty falling asleep on Sundays.

According to a new survey conducted by online panel provider Toluna Omnibus, 39 percent of more than 3,000 respondents say they have the most trouble drifting off on Sundays. That’s more than double the percentage who had the hardest time on Saturdays, the runner up, at only 19 percent. (It’s worth noting Americans are not alone here: Brits are in the same sleepless boat. A 2008 survey of 3,500 workers found that 60 percent said falling asleep was toughest on Sundays, the BBC reported.)

So what’s so special about Sundays? We may have trouble catching our 40 winks thanks to a phenomenon that’s been dubbed “social jet lag,” sleep specialist Michael J. Breus, Ph.D., who consulted on the survey, tells The Huffington Post. Staying up later on Friday and Saturday nights — and consequently sleeping in on Saturday and Sunday mornings — essentially shifts the entire biological clock, he says, as if you had traveled across time zones. “When Sunday night comes around, your body is used to staying up later and sleeping later,” he says, and suddenly you’re frustratedly counting sheep.

The other factor is likely stress, says Breus. Of those who are employed full-time, 48 percent identified Sunday as the most difficult night to fall asleep, and 43 percent of homemakers felt similarly, reflecting the effects of stress about the week ahead, he says. Only 36 percent of unemployed respondents and 27 percent of students identified Sunday as the hardest night to fall asleep.

Of the 39 percent of people who said they struggle on Sundays, 70 percent said it takes them 30 minutes longer than usual (or more!) to finally doze off, according to the survey. Tuesdays and Thursdays were dubbed the easiest nights to fall asleep with just 5 percent and 3 percent of people citing trouble on those nights.

The best way to beat social jet lag is to stick to your regular sleep schedule all weekend long, says Breus. Yes, that’s tough if you feel like a late dinner out on Friday night or lounging in bed until it’s technically Sunday afternoon, but doing so “is just going to cause more problems,” says Breus. And if it’s stress that’s keeping you up, Breus suggests spending some time jotting your thoughts down in a worry journal. There you can include to-do lists, goals and lingering worries from the prior week to address when Monday morning rolls around, he says. “That way, Sunday night, you’re not spending all night in bed stressing out.”

Of course, good sleep hygiene is always important, seven days a week. Your bedroom should be cool, dark and quiet, and free of distracting and light-emitting electronics.

Does your sleep vary depending on the day of the week? Tell us about it in the comments below.