It’s no secret that Orangetheory Fitness is one of the fastest-growing boutique workout franchises in the country—1,000 locations and counting so far, plus almost 300 international outposts. It seems like studios are opening on practically every corner (and even into hotels). Suffice it to say, plenty of people are talking about taking one of these classes at the moment, but also: Few are saying it’s easy.

If you’re not familiar, Orangetheory is known for being a buzzy HIIT workout that’s made up of three stations (treadmill, weights, and rowing machines), and it tracks your heart rate throughout the sesh so you know where you’re at. If you really want to try one out but are a bit nervous—I feel you—there are some key things you can keep in mind to make it feel less, well, intimidating. For starters, know that the workout was specifically designed so that anyone could do it. In fact, Orangetheory Fitness co-founder, Ellen Latham, says she just finished training with a 78 year-old woman who does the class three times a week. Talk about #goals.

Here are four things every newbie should know before your first Orangetheory fitness class, according to the studio’s co-founder Ellen Latham.

1. Prepare to put the “theory” into practice

Before class, each participant is fitted with a heart rate monitor to track how long they’re in the “orange zone” (or 84 percent of their maximum heart rate) while working out. “You have to get your heart rate [past that threshold] for 12–20 minutes in a workout in order to achieve a metabolic response,” explains Latham, who’s also an exercise physiologist. “The theory is that of interval-training and EPOC, or afterburn—which stands for post-exercise oxygen consumption.” That means you’ll keep burning calories even when you leave class.

Each day has a different focus—like strength, power, endurance, and so on, which dictates what stations and moves make up the class. So, you may alternate between cardio time on the treadmill (where you listen for cues for the category you decide you’re in—walker, jogger, or runner), the row machine, TRX straps, weights, etc.

2. Avoid comparing yourself to others in the class

Sure, you’re shoulder to shoulder with a lot of strangers—but it’s still your workout. “Approach your first Orangetheory class very individualized,” Latham advises. “Never compare yourself to someone else and never think that you’ve got to do everything perfect; that is never expected ever.”

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In addition to offering three categories of cardio work for complete customization, Latham says every coach is trained to help modify the strength-training portion of the class as well. “You’ll always have options for the floor work—whether you’re someone who has bad knees or you can’t get up and down off the floor easily, or anything else you may have going on in your body,” Latham says. The bottom line: You do you.

3. 12 minutes in the orange zone is a goal, not the expectation

The workout can be intense, so baby steps are key. Even if you’ve done interval-training classes before (like Barry’s Bootcamp, for example), Latham says sustaining 84-percent of your max heart rate for a full 12 minutes is something you may not attain if you’re new to Orangetheory.

“That is your goal one day, be it two weeks or four weeks down the line,” says Latham. “Or maybe you got two minutes in today, then you shoot for four minutes the next time and six minutes the next.”

4. The workout should feel challenging, but not run you down

Gone are the days of aiming to leave a workout so sore you can hardly move. “The old adage of leaving [feeling like] someone beat you up is no longer the case,” says Latham, who adds that at Orangetheory, the goal is to be uncomfortable for 12 minutes and to push yourself to spark change in your body, not be in pain.

Her best advice? “Go at your own pace—do the advanced pushes and sprints, but you should not get to the point where you want to crawl out of class.” Even so, you may want to have your foam roller handy post-class, just in case.

Originally published January 23, 2018; updated September 23, 2019, with additional reporting by Kells McPhillips.

If you’re looking for some recovery tips, try these foam roller moves that can help you de-stress, too. And here’s how to use a massage ball to soothe sore muscles.