Halfway through my first day at the boxing gym, I was certain of two things: one, that I was going to quit, and two, that I was going to puke. It was only the order of those things that had yet to be determined. I’m a comic-book nerd whose high school claim to fame was a supporting role in a class production of Damn Yankees. Although I learned my way around a gym in college, I still had no business running drills with a coach who had two honest-to-God UFC fights under his belt. When the timer blared, I collapsed to the floor, drenched in sweat, and decided that I lived there now. This was my floor, and nobody would take it away from me until the moment I died, which, I was still pretty certain, was only about five minutes away anyway.

An hour after I left, I seriously considered going back for a second session that day.

All new fitness endeavors can be intimidating as hell, and few disciplines make the contrast between the initiated and the uninitiated feel quite as stark as boxing does. But as is the case with all new fitness endeavors, the hardest part is showing up—I don’t know many people who give it a whirl and then don’t come back for more. If you’re tired of treadmills and weight rooms and have been eyeing the gloves with curiosity, here’s what to expect in your first class.

Be ready to keep up—and fall behind

There’s a better-than-decent chance that you’re going to be the day’s only newbie, and that the class will otherwise consist of people who have at least a decent grasp on what they’re doing. And while your coach will make sure that you know what you need to know, and teammates will offer breathless encouragement, it’s your responsibility to do everything you can to keep up.

If you fall behind—again, the chances here are pretty good—that’s fine! Everyone else had a first day once upon a time. Also, boxing is a workout, but it’s also a skill, and learning new skills takes time. This isn't a turn-the-treadmill-on-and-go situation. As long as you’re working hard and have the right attitude, folks will acknowledge the effort and respect the hustle.

It’s not just punching each other

The agenda will likely consist of some combination of these activities:

Shadowboxing: This is the cool thing you see action heroes doing in training montages. Shadowboxing consists of throwing punches at nothing, rather than at a pad, heavy bag, or some other specific target. It’s great for warming up, and for adjusting your form.

Mitt work: Your coach or a teammate will hold thick pads over their hands and have you hit them in specific combos. They’ll go over the combos beforehand, so don’t worry—this is not an exercise in improvisation. Mitt work helps develop accuracy.

Heavy bag rounds: This is the part you’re probably most excited about: drilling combos into a punching bag, usually in three-minute rounds. While mitt work and shadowboxing are more focused on technique, this is where you just pound away at your target, more or less. Pro tip: It is going to wear you out faster than you think.

Conditioning: Jumping rope, push-ups, sit-ups, squats, and other basic gym staples feature heavily in boxing workouts. Don’t expect biceps curls, though, or even pull-ups. The selections will almost always be body-weight exercises, the kind of thing you can do at home on your own.

The pace will move quickly, and breaks will be short. Most coaches take between 30 seconds and a minute between rounds, but will often substitute longer breaks with “active recovery.” This means that you’ll work a heavy bag for three minutes and then “recover” with, say, a minute of sit-ups. Throughout, you’ll be periodically prompted to maintain your form, adjust your feet, and keep your hands up to guard your chin—because although doing so eventually becomes second nature, on your first day, you will definitely forget.

Watch:Muhammed Ali Was The Greatest of All TimeEmbrace your naïveté

Nobody likes feeling like a doofus in front of a bunch of extremely fit people who are literally training themselves to punch stuff better, especially when there are plenty of other exercise options out there that you already know how to do. As previously discussed, there will be a point during that fateful class at which you decide that this whole Rocky thing isn’t for you, and that although this was kind of a fun lark, it’s high time to head back to the weight room.

Don’t! Think about it this way: One of the great secrets the world keeps from you is that being cheerfully bad at things is low-key kind of fun. Learning a new skill—and tracking your progress from terrible to less terrible to good—can be a lot more rewarding than repeating the same stale fitness regimen to which you’ve adhered since high school. Boxing is always going to push you, and it’s always going to hurt. But as long as you make it through that first workout, every session after that is going to be a little bit easier.

Plus, it’s 100 percent okay to lie and tell your friends that you knocked somebody out on day one. How will they ever find out otherwise?

Tres Dean is a contributing writer for GQ specializing in sports, fashion, and the intersections between the two (which most often means covering sneakers). Outside of the going-ons of the sneaker world, he’s profiled athletes like Zion Williamson, defended the valor of reviled directors, and interviewed Travis Scott from the... Read moreXInstagram