Get smart about your workout and you'll burn calories long after your sneakers are off

By Sara Angle
March 12, 2015
Orangetheory Fitness

Many workouts tout the effect of burning extra calories even after the hard work is done, but hitting the sweet spot in order to maximize afterburn all comes down to science.

Excess post-exercise oxygen consumption (EPOC) is the physiological theory behind classes that increase your metabolism for 24-36 hours after your workout ends. Orangetheory Fitness is one national brand that's capitalizing on that process to help their clients lose weight and get fitter.

OTF's 60-minute classes use treadmills, rowing machines, weights, and other props, but the real secret is in the heart rate monitors they give every client to wear. Monitoring your heart rate is key to ensuring that you hit the right zones you need for EPOC to kick in, explains Ellen Latham, founder of Orangetheory.

"When I get clients working at 84 percent of their maximum heart rate-what we call the orange zone-for 12-20 minutes, they're in oxygen debt. Think of it as that period of time in your workout when you feel like you can't catch your breath. That's when lactic acid builds up in your blood stream," explains Latham. EPOC helps break down that lactic acid and help speed up your metabolism. (Here's how to find your maximum heart rate.)

Because you've shocked your system so much (in a good way!), it will take over a day to get back to normal. During that time, your metabolic rate actually increases by about 15 percent of your original caloric burn (so if you burned 500 calories in your workout, you'll burn an extra 75 afterwards). It may not sounds like a ton, but when you're working out at those levels 3-4 times a week, those calories add up.

To know for sure you're working hard enough, you'll need a heart rate monitor. It may seem like a big investment, but being able to measure yourself is vital for weight loss. In fact, Latham believes in the science so much that members at Orangetheory get their own monitors to keep.

The best part is you don't necessarily need to be working at 84 percent of your maximum heart for a consistent 12-20 minutes-that time can be spread throughout your workout. So ease into a challenging but doable pace for the majority of your workout, throw in a few all-out pushes, and you'll be burning calories long after you've left the gym.