The thrill of discomfort in the gym is honestly what keeps us showing up time after time. Because that’s how you know it’s actually working, right?

While some of us thrive on high-intensity, others are trying to get their body right for a big event or looking to PR the next race while they’re in the gym. And in each of these instances hardcore workouts and group fitness classes will do just the trick. Thankfully, ClassPass scanned reviews and crowdsourced data from classes and studios across the United States to bring you a list of the toughest studios out there to help you accomplish whatever your goal may be. 

So the next time you’re scouting out classes on ClassPass that make you feel like you’re going to throw up — but will still have you coming back for more — check out a few of these options.