Photograph by Marshall Clarke.

TRX

Graham’s Maximum heart rate: 161

The TRX is a strap that hangs from a hook and has adjustable handles so you can do exercises such as suspended push-ups (with your feet in the straps) or pull-ups. A one-hour class at Crunch Fitness, featuring aerobics and strength training, is fast-paced and fun. Chevy Chase DC, 202-621-7622; Metro Center, 202-621-6698. Drop-in fee $15. Free pass available online.

Photograph by Madeline Tank.

Bikram Yoga

Maximum heart rate: 165

An otherwise moderate, 90-minute yoga class at DC’s Bikram Yoga Tenleytown turns into a heart-pounding sweatfest in a studio that’s at least 105 degrees—and often higher. The brutal heat does allow you to find your full range of flexibility. Graham felt great the next day. 202-243-3000; dcbikramyoga.com. Drop-in fee $18.

Photograph by Madeline Tank.

Kettlebells

Maximum heart rate: 164

A one-hour Maryland Kettlebells class offered the best instruction we’ve seen using these cannonballs with handles. A variety of full-body exercises such as windmills—deep side bends done while holding a kettlebell overhead—develop strength and coordination, and the intensity builds as the class progresses. Prepare to be sore the next day. Silver Spring; 443-742-1224. Drop-in fee $20; first class free.

Photograph by Madeline Tank.

High-Intensity Training (H.I.T.)

Maximum heart rate: 163

While this one-hour class at the Northwest DC Sport & Health Club didn’t score the highest heart rate, it’s Graham’s pick for the most intense: His heart rate consistently stayed above 150 while he was performing lunges, push-ups, plyometric jumps, calisthenics, and weightlifting in repeating circuits. Multiple area locations; sportandhealth.com. Drop-in fee $20. Free one-week membership available online.