{"id":66742,"date":"2017-04-04T06:48:12","date_gmt":"2017-04-04T06:48:12","guid":{"rendered":"https:\/\/breakingmuscle.com\/\/\/uncategorized\/the-myth-of-interval-training-and-epoc"},"modified":"2022-10-24T12:13:40","modified_gmt":"2022-10-24T17:13:40","slug":"the-myth-of-interval-training-and-epoc","status":"publish","type":"post","link":"https:\/\/breakingmuscle.com\/the-myth-of-interval-training-and-epoc\/","title":{"rendered":"The Myth of Interval Training and EPOC"},"content":{"rendered":"

You may have heard of EPOC, or as it\u2019s commonly known, the \u201cafterburn\u201d effect. Recently, it\u2019s been widely publicized as an explanation for the benefits of high intensity interval training (HIIT). People claim that interval training is better than continuous cardio,<\/strong> and specifically that interval training is more effective for weight loss or fat burning because it increases EPOC more than continuous cardio. By that logic, you burn more calories after you finish interval training, which leads to weight loss. It\u2019s such a common argument that it must be true, right?<\/p>\n

Nope.<\/strong><\/em> This is a case of research being taken out of context and misrepresented to provide an argument for one type of exercise over another. This happens way too often<\/a> in the fitness industry. Let\u2019s dispel this myth right now so you can make an informed decision about your cardio training.<\/p>\n

What is EPOC?<\/h2>\n

EPOC stands for Excess Post-exercise Oxygen Consumption. It\u2019s an increase in oxygen uptake above resting levels that occurs after exercise. Increased oxygen consumption requires energy, so EPOC means that you burn calories even after an exercise bout.<\/strong> The purpose of EPOC is to restore the body to its resting state and create physiological adaptations which will help the body handle the same amount of exercise-related stress more easily in the future.<\/p>\n

EPOC is the greatest immediately after exercise. Some studies have found that EPOC lasts up to 24 hours, while others have found it to be much shorter, less than an hour in some cases.1<\/sup><\/a> The large range of EPOC durations across studies has been attributed to differences in exercise intensity and duration, as well as differences in study methodologies.<\/p>\n

Despite sensational claims from some in the fitness industry, research suggests that the EPOC effect is fairly small,<\/strong> and probably makes only a minor contribution to weight loss compared to the energy cost during the actual exercise. The amount of extra energy burned during EPOC is only about 6-15% as much as is used during the exercise itself.2<\/sup><\/a> For example, 20 rounds of 1-minute running intervals performed at 105% of VO2max, separated by 2 minutes of rest, burned an average of 537 calories during exercise, and an extra 64 calories in the 9 hours after the session.3<\/sup><\/a><\/p>\n

Research has also demonstrated large individual differences in EPOC responses.1<\/sup><\/a> That means that two people who do the exact same workout would likely burn different amounts of calories both during and after the session, based on differences in their gender, age, physiology, training status, and lifestyle factors such as diet, sleep, and stress. Keep that in mind next time you hear that a certain workout or exercise will burn X number of calories, or when you look at the calorie counter on your treadmill or exercise app. Chances are, it\u2019s not accurate for you<\/a>.<\/p>\n

The Root of the EPOC and Intervals Myth<\/h2>\n

The magnitude of EPOC increases exponentially with increased exercise intensity for the same distance or time.1<\/sup><\/a> In other words, if you run five miles in 25 minutes, you are going to get a larger EPOC effect than if it takes you 50 minutes<\/strong> to run those same five miles. If that\u2019s the case, it would make sense that intervals, which are performed at a much higher intensity than continuous cardio (also known as steady-state cardio), would have a much greater EPOC effect.<\/p>\n

That idea has been suggested as one reason for the similar weight or fat loss observed between interval training and continuous cardio, despite the much lower exercise volume needed for intervals to achieve those results. As interval research became more well-known, the idea of a greater EPOC effect became more widely publicized.<\/p>\n

Although this explanation makes logical sense, studies that have directly investigated EPOC between interval training and continuous cardio don\u2019t exactly back up the theory, especially when you consider the research in terms of its real-world application.<\/p>\n

What Does the Research Say?<\/h2>\n

Studies have shown that when energy expenditure is measured for several hours after a training session, intervals and continuous cardio burn about the same amount of post-exercise calories.<\/strong><\/p>\n

Three studies found that participants burned a similar number of calories in the hours after they did either interval training or steady state cardio, but the interval session only required 20 total minutes (only about 2-10 minutes of high intensity exercise) while the steady state cardio session lasted for 30, 50, or 60 minutes.4<\/a>,5<\/a>,6<\/a><\/sup><\/p>\n

Another study matched the exercise bouts by duration, so participants did about 45 minutes of interval training, 45 minutes of resistance training, and 45 minutes of continuous cardio. EPOC was higher after interval and resistance training than continuous cardio, with participants burning about 12 calories per hour more after intervals compared with continuous cardio.7<\/sup><\/a> Of course, one of the major benefits of interval training is the ability to get similar fitness improvements and weight loss results with a much shorter exercise time than steady state cardio, so matching the duration of the interval session with continuous cardio sort of defeats the purpose<\/strong> in terms of the way people actually exercise in real life.<\/p>\n

Based on those studies, it does appear that interval training has a greater capacity to induce EPOC than continuous cardio. It only takes a relatively short time for intervals to create the same amount of EPOC as continuous cardio, although the exercise needs to be done at a much higher intensity to get that effect.<\/p>\n

Where Research Meets the Real World<\/h2>\n

But now let\u2019s think about this in terms of its practical implications. <\/strong>I\u2019ll use the data from the Skelly study5<\/sup><\/a> as an example. In that study, participants breathed through a mouthpiece, and their exhaled air was analyzed to measure oxygen consumption and calculate their energy expenditure. Expired air was collected every few hours over a 24-hour period, including for one full hour during which participants rested or exercised. During that hour, they either rested for the entire hour, rested for 10 minutes and then cycled for 50 minutes continuously at a moderate intensity, or rested for 40 minutes and then did 10 x 60-second high intensity cycling intervals with 60 seconds\u2019 rest in between. During those one-hour periods, here\u2019s the average number of calories they burned:<\/p>\n