The scientific reason why you like to work out until it hurts

You’re 30 minutes into your spin class, dripping in sweat, and your heart is racing. Your instructor tells you to add more resistance and go faster. Even though you’re already breathing hard, you reach down and give the knob a big turn to the right. Admit it: Sometimes, unless you leave a workout feeling completely spent, it almost doesn’t feel worth it. And it turns out there’s a scientific reason for that.

When you sit most of the time—at work, on the couch, in the car—it can actually be pleasurable to experience what it feels like to push your body to the limit.

Researchers at the University of Cardiff in Wales studied why exactly people enjoy intense workouts so much—to the point where it actually hurts. “Pain brings the body into sharp focus, allowing individuals to rediscover [it],” the study reads.

As the researchers explain it, when you sit most of the time—at work, on the couch, in the car—it can actually be pleasurable to experience what it feels like to push your body to the limit. The Guardian points out that extreme sports, like ultramarathons, are most popular in countries where people have the luxury to sit in an office all day. They aren’t so popular in places where people are primarily doing hard labor.

Another reason why intense workouts can be so pleasurable? Escapism.

Another reason why intense workouts can be so pleasurable? Escapism. In other words, it’s more enjoyable to focus on your aching muscles than a fight with your partner. Is it any wonder running to get over a breakup or divorce is so popular?

Going hard during a workout is a pretty darn healthy way to get in touch with your body. (You know, within reason.) Just be sure to stretch afterward—that (slightly uncomfortable) foam roll, ultimately, will help your body bounce back after any high-intensity sweat session.

If intense workouts are your thing, try one of these hardest-ever fitness classes. And this is the most difficult move you can do at the gym.