Do you sleep on your back, side, or stomach? For one in five, it’s all of the above.

That’s according to a new survey of 2,000 respondents, conducted ahead of World Sleep Day.

Did you know that 22% of those polled switch up their sleeping position every single night?

Not surprisingly, two out of three (64%) identified themselves as restless sleepers, citing anxiety (26%) and snoring partners (20%) as the biggest catalysts of their tossing and turning.

And that tossing and turning seems to have consequences – only one in ten (10%) said they feel refreshed every single time they wake up in the morning.

Conducted by OnePoll on behalf of Purple Innovation, the data also suggests that the majority of people (42%) prefer to sleep on their side, almost twice as many as those who called back-sleeping (18%) or stomach-sleeping (17%) their favorite position.

That proved less true for millennial respondents though (ages 26-42), who were most likely to sleep on their stomachs (19%) and least likely to sleep on their sides (38%).

Interestingly, Millennials were most likely to change their sleeping position to accommodate neck pain (38%) – but also the most likely to report their sleep quality as “good” (73%) compared to the panel as a whole (66%).

Regardless of demographics, pain ended up being a big sticking point for most respondents. Over half (53%) have attempted to deliberately change their sleeping position, most frequently to ease soreness (28%) or improve their quality of sleep (28%).

Out of those polled who’ve experienced soreness, back pain (36%) emerged as the most common complaint, followed by neck pain (33%) and shoulder pain (24%).