For those who can’t deal with waking up at the crack of dawn for an early-morning workout (same), having the flexibility to sign up for a nighttime HIIT class is a true blessing—and seemingly the only way to stay on top of your fitness goals. There’s no snooze button getting in the way, and you get to unleash some of that pent-up tension accumulated from your long day at work. But are those pesky rumors about intense nighttime sweat seshes negatively affecting your sleep true? Not if you time them out right, according to awesome new research.

In a meta-analysis of 23 studies published in the journal Sports Medicine, it was found that vigorous evening workouts—the ones that are so intense that they literally leave you speechless—were totally fine to do. The one caveat? Best practice for the workout not compromising your sleep game is to leave at least an hour between the end of your training sesh and the time you hit the sheets.

Researchers hypothesize that completing an intense workout and going to sleep within an hour isn’t optimal because the body isn’t able to properly recover.

Those who completed an intense workout and then essentially immediately tried to go to sleep had some trouble dozing off, and researchers hypothesize this happened because the workout warriors weren’t able to properly recover. Their hearts were still beating fast in those 60 minutes after—nearly “20 beats per minute faster than their resting heart rate,” explain the study authors. Moderate training shortly before bedtime, on the other hand, didn’t show any negative affects: Since the sessions weren’t as intense, those individuals were able to recover faster, heart-rate-wise, and fall asleep normally.

So if you do want to attend those late-night HIIT classes, just make sure to schedule them in such a way that your bedtime won’t suffer. As long as you have a good hour between the time you finish and the time you lie your head on that soft, fluffy pillow, you’ll be just fine.

Want to get fit quickly? Try 10-minute micro-workouts. Or, check out the audio-only workout apps that are going to transform your fitness routine for the better.