Why Lo Bosworth stopped doing high-intensity cardio

In the 10 years since The Hills debuted on MTV, Lo Bosworth’s embarked on a major wellness journey (not unlike her pals Lauren Conrad and Whitney Port): She’s opened up about her struggle with anxiety and depression, went to culinary school, and started her own line of feminine care products, for starters. And now, the ex-reality TV star is offering some real talk about exercise—specifically why she cut certain cardio workouts, like bootcamps and HIIT classes, out of her fitness routine.

“I used to be a really high-impact exercise girl, and I found that it definitely changed my body, but it wasn’t the exercise that made me feel the best all around. I hurt my back and I hurt my knees because of all the burpees and the jumping,” Bosworth tells me during a Matcha Mornings talk at cafe/spa Chillhouse. (Her former co-star Kristen Cavallari also nixed cardio workouts, which may be the only thing the two have agreed on since season one of Laguna Beach, BTW.)

So, where can you find Bosworth working out these days? “My go-to studio is SLT; I try to go at least four days a week. And I’ve found that taking a step back and doing something like SLT—which is, to me, just as intense of a workout—changes my body, maybe even more. But it’s just so much more low impact; I think that it’s so much kinder on my body, and it’s changed the way I feel about working out: I’m excited to go.” (Modo Yoga, and Equinox Gym are her other mainstays at the moment.)

But it wasn’t just a fear of injury that led her to rethink the way she works out. She says, “When I first started to feel kind of funky, I could throw myself into a panic attack in a workout class, and my doctor was like, ‘Well, it’s because your heart rate’s up, your cortisol levels are up. I’ve approached a slower, gentler way of working out in the past year, and it’s helped me.”

Here are 3 ways to tell if you’re doing enough (or too much cardio). Plus, this is the best workout a master trainer bets you’re not doing—but should.