How we burn more calories for hours after an intense workout
Today, our FitCamp workout was designed to keep the heart rate at about 85% – 90% of HRM (heart rate maximum) using HiiT (High Intensity Interval Training). We performed six exercises using a 10 round tabata (:20 work with :10 rest) for 5 minutes of continuous work/rest per each exercise. After the tabata rounds were over, we ended with a 3-exercise metabolic finisher. As a result, we took the body to failure a few times and increased our body’s demand for oxygen as we were all “sucking wind” at the end of each tabata set and at the of the workout. As I mentioned in class, this not only burns calories DURING the workout, it also creates what some people call “after burn” or EPOC (Excess Post-Exercise Oxygen Consumption).
After we warm up and begin more intense exercise, our body must choose which energy system to used based on our intensity level. While the body is adjusting, it starts taking in more oxygen until we get our “second wind” when our oxygen demands are eventually met. That’s why running is so uncomfortable for some people. They give up before they ever get to that “second wind” state. HiiT messes with this a bit as we take our heart rate up and then drop it several times throughout a workout.
So… when we finally stop exercising and we don’t need to tap into those energy reserves, the body continues to take in more extra oxygen that we normally would during lower-intensity workouts. This excess oxygen, what we refer to as EPOC or Excess Post-Exercise Oxygen Consumption, is used for recovery processes that bring the body back to steady or normal state.
The intensity and duration of our HiiT workout determines how long it takes for our body to return to normal, thus affecting the “after burn”. When we don’t exercise hard, we don’t get a noticeable after burn. After high-intensity exercise, however, the after burn can last hours or even days. I’ve had clients who have reported that their kcal count continued to climb as much as 300 kcals in the first hour after a 500 kcal effort. That intense after burn will not stay that high for more than a couple of hours at most. However, even 24-48 hours after the workout, you might still see an extra 25 kcals being burned in an hour.
So why is this important?
Simply put, the more intense your workouts, the more energy you will expend to assist with the recovery after the workout. Thus, the longer the recovery period, the longer your body will continue to burn calories.
By incorporating some high-intensity workouts (85% – 90% of HRM) in your weekly routine, you will not only burn more calories during the workout, but you will burn additional calories during the recovery period.
Doing time-based workouts with intense bursts of energy followed by short periods of rest are ideal. Tabatas (:20 work, :10 rest) are good. So is sprinting for 10 seconds, jogging for 30 seconds or jumping rope for a minute and resting for 30 seconds. Do at least 30 minutes of HiiT a couple of times a week.