When you work out hard, did you know you can continue to burn fat long after exercise? This all-day burn is called Post Exercise Oxygen Consumption (EPOC). When you exercise at high intensities, your muscles begin to fatigue, and your body’s oxygen stores become depleted. Your body works hard to replace its oxygen debt, and this is the after-burn feeling you get.
When you work out, your body is put under stress, and it depletes your body’s energy stores. These energy stores are called ATP (adenosine triphosphate), converted by the metabolism from the nutrients you consume. After exercise, your body wants to work hard to return to its normal state and replace the ATP you used up. Therefore the more calories you burn, the more calories you need to replace it.
This next part gets a little scientific so try to stay with me.
When you exercise, your body burns energy in two ways aerobic (oxygen) and anaerobic (lack of oxygen), and your body produces ATP more effectively aerobically. However, at high intensities, ATP is used by the body more quickly anaerobically. The higher intensity exercise asks the body to use oxygen to make more ATP for energy to the muscles during training. This creates a more significant oxygen debt, which makes for a high EPOC. Therefore your “after-burn” is more elevated.
Why EPOC is Important
Compared to steady-state exercise, strenuous exercise produces greater EPOC when performed at the same amount of time. Your body uses 5 calories of energy to consume 1 liter of oxygen, so increasing the oxygen deficit during exercise causes more calories to be burned overall.
In addition, longer sessions show a greater EPOC response than shorter sessions. However, the intensity is the main contributor of EPOC because of the anaerobic pathways used. Remember, anaerobic pathways are those that do not need oxygen to function. Overtime incorporating high-intensity exercise improves your body’s ability to use oxygen for energy, and you can exercise at a high intensity longer. It is recommended for endurance athletes to incorporate high-intensity workouts into their regime to boost energy at the end of a long run.
Strength Training and EPOC
Strength training has been found to produce a greater EPOC effect than running alone. When designing a resistance training program to have the greatest afterburn, studies suggest super setting is key. This means moving from one exercise to the next with minimal rest in between.
A study found that super setting produced 33% greater EPOC, which burned about 240 calories in a 60 minute recovery period. In addition, you can also increase the intensity of strength training by using heavier weights that put stress on the muscles. One study compared heavy resistance exercise, circuit weight training, and aerobic cycling. It concluded that heavy resistance training produced the greatest EPOC.
The Bottom Line
The take-home message here is switching up your routine can produce lasting results. Although high-intensity training requires a more extended recovery period, it increases one’s exercise capacity in addition to calorie burn. These workouts should be extremely challenging, and you should allow yourself to recover at least 48 hours in between.
It is recommended to have this training about three days out of the week, and on the other days, steady-state exercise is recommended to increase blood flow to those areas. It is important to note that exercising to achieve greater EPOC is only a piece of the puzzle, and one should still incorporate many techniques to achieve optimal results.