Work off some serious calories—or a morning bun from Tartine—with three intense, heart-pumping classes.

1. TRX Circuit Training

TRX Training Center, Russian Hill
Calories Burned: 300–600

The Workout: Invented by a former Navy Seal right here in SF, the equipment is pretty basic: 12-foot-long nylon straps, a couple of buckles, and two loops dangling from a secure bar or anchor point in the ceiling. During any of the 55-minute-long circuit training group classes (held two or four times a day, Monday through Saturday), you'll move through a fast-paced set of pull-ups, presses, curls, and core work. The idea is to use your body weight for resistance to build strength, as you switch from floor exercises with your feet cradled in the loops (hello, side plank) to inclined standing sets with your hands gripping the loops for leverage during modified push-ups and single-legged squats.
The Payoff: “Sometimes I’ll do three classes in a row to burn off the delicious calories in the chicken adobe burrito at Papalote,” says Medwin Mina, a martial arts instructor who lives in Portola Heights. “I weighed more than 300 pounds at one point. The struggle is always there, especially for someone who loves food.”
Do It: Drop-in classes at the training center cost $20; free to all club members. 1650 Pacific Ave., 415-655-4797, trxtrainingcenter.com

*Special: Get a free week of TRX Training with promo code: 7x7WEEK

2. Zumba
Club One, various locations
Calories Burned: 300–600
The Workout: The one-hour Zumba class at Club One moves fast. Like, really fast. The dances based on cumbia, merengue, tango, salsa, belly dance, and samba (Zumba bills itself a “Latin-inspired dance-fitness party”) are fun and challenging. There are no breakdowns of the different steps, so you’re expected to keep up as best as you can or until the track changes and the instructor goes on to the next thing. If you have trouble following the moves, call her over so you can dance next to her and mimic the choreography. The quick changes boost your heart rate, increase coordination, and build muscle strength—and keep you from getting bored. Sound like a dance marathon? It is, so bring a towel and lots of water.
The Payoff: “I go once a week to have fun and let go,” says Jennifer Moffitt, a high school English teacher in the city. “It’s kind of a crazy break from conditioning workouts and contemplative yoga.”
Do It: A one-day pass to Club One costs $20; free to all members. 1455 Fillmore St., 415-749-1010; 1 Sansome St., 415-399-1095; 2 Embarcadero Center, 415-788-1010; 950 California St., 415-834-1010; 350 Third St., 415-512-1010, clubone.com

3. Spinning
Sports Club/LA, SoMa
Calories Burned: 300–500
The Workout: At Sports Club/LA, the high-intensity VideoREV classes put you through speed drills, presses, anaerobic threshold sprints, and climbs that test indoor cyclists’ limits over an uninterrupted 50 minutes. To keep you going, it’s nice to have something to focus on, like a couple of TVs showing inspiring bike races and dance-happy music videos (there’s a lot of Jackson 5 and 1980s Madonna on play) synched to your real-time workout. On Wednesday evenings, instructor Michael Walker rides along with you up and down steep peaks and valleys that bump up your cardio to help you burn fat. Suggestion: Wear a heart-rate monitor. And expect to come away soaked in sweat.
The Payoff: “I emerge breathless, exhausted, and red as a tomato, but it’s worth it,” says Monica Lim, a business development director in Bayview. “I live to eat, and spinning helps me offset my indulgences, like a double scoop of stout-and-pretzel ice cream from Mr. and Mrs. Miscellaneous.”
Do It: A one-day pass at Sports Club/LA costs $35; free to all club members. 747 Market St., 415-633-3900, thesportsclubla.com

For a March special at TRX Training Center, enter the promo code 7X7WEEK when you sign up for classes online. Offer expires March 31st!