There are plenty of benefits to our HIIT workouts that keep you coming back. You love the fact that each time you’re guaranteed a really great workout. Your busy schedule loves the fact that you’re in and out in less than 45 minutes. The trainers and fellow members are inspiring. And then there’s that whole “afterburn” phenomenon. You really dig that . . . you think?
If you’re a bit sketchy on the exact details of the afterburn effect, buckle up for a kinesiology lesson. The official name for what we’re talking about is excess post-exercise oxygen consumption, EPOC for short, and it refers to the oxygen your body needs to restore itself to your pre-workout state. When you exercise, your body uses oxygen (or aerobic pathways) to produce fuel called adenosine triphosphate or ATP. When you perform high-intensity exercise, such as at FIT36, your body also taps into ATP stores in your body that don’t require extra oxygen (or anaerobic pathways) during the workout, but do need a higher amount of oxygen afterwards to bring your body back to homeostasis. It’s this need for extra oxygen that leads to a higher-running metabolism after your workout ends.
After any workout, oxygen is utilized post-workout for replenishing ATP, repairing taxed and strained muscles, adjusting muscle glycogen and lactate levels, and to restore your body temperature to its regular level. But after a HIIT workout your body uses a lot more oxygen in the hours following.
And the higher-intensity a workout is, your body will require more time and oxygen to replenish your ADP. Your body burns 5 calories to consume one liter of oxygen. So, if your workout leaves you breathless, sweaty, and with a temporarily-raised heart rate, your calorie burn rate is going to be higher than after other, less-challenging workouts. Also, the greater amount of muscle you have, and the more muscles that were worked during your workout, the more calories you’ll burn during and after your exercise session ends.
The American Council on Exercise reported online that high-intensity interval training is the most effective form of exercise to stimulate the EPOC, or afterburn, effect. More than running, and more than other aerobic classes. This is because when you exhaust your ATP stores and force your body to rely on anaerobic pathways rather than aerobic pathways, you produce a temporary oxygen deficit that requires hours of post-workout oxygen use, leading to hours of increased calorie burn. Also, EPOC rate is determined by the intensity of your exercise, rather than the duration – hello, 36 minutes!
Want even more EPOC bang for your buck? Consider using slightly heavier weights when you lift. And during HIIT sessions aim to be the overachiever student; raise your knees a little higher when running in place, position your hands to make your pushups a little more challenging, do the extra squat jump during your burpee set. And be sure to always allow yourself a day or two of recovery after each HIIT session. This recovery period actually helps your muscles to develop to their potential, and will ensure that you keep seeing gains and improvements in your own athletic performance.