Research institute epoc

NASM Research Update A 45-minute vigorous exercise bout increases metabolic rate for 14 hours.

Knab, A.M., Shanely, A., Corbin, K.D., Jin, F., Sha, W., and Neiman, D.C., (2011). A 45-minute vigorous exercise bout increases metabolic rate for 14 hours. Medicine and Science in Sports and Exercise, 43:1643–1648.

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Introduction •

Upon termination of exercise, oxygen consumption (VO2) gradually returns toward baseline levels, but can remain elevated for varying periods of time. o This VO2 consumed above resting values during this phase is referred to as the excess postexercise oxygen consumption (EPOC) or ”afterburn.”

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Early research led us to believe that EPOC played a large role in weight loss, and contributed greatly to the overall caloric expenditure of exercise. However, much of the EPOC research conducted in the 1990s through early 2000s that created optimism concerning EPOC’s critical role in weight loss is largely unsubstantiated. o The studies that did elicit substantial EPOC (e.g., > 100 kcal) generally consisted of regimens that were high in intensity or long in duration, or both.

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Introduction •

In most circumstance, these types of programs would not be well tolerated by non-athletic populations.

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Many of these studies were conducted using gas analysis techniques that are prone to some error. However, the magnitude and duration of the elevation in resting energy expenditure after vigorous exercise has not been measured in a metabolic chamber, considered to be more accurate than gas analysis.

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Study Overview •

This study investigated the effects of a 45-min vigorous cycling bout versus a controlled resting day on 24-hour energy expenditure conducted in a metabolic chamber.

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Ten male subjects (age = 22-33 years) completed two separate 24-hour chamber visits (one rest and one exercise day), and energy balance was maintained for each visit condition.

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On the exercise day, subjects completed 45-minutes of cycling at approximately 73% of VO2max (equivalent to > 85% of maximal effort).

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Activities of daily living were tightly controlled to ensure uniformity on both rest and exercise days.

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Results • The 45-minute exercise bout resulted in a net energy expenditure of 519 kcal (± 60.9 kcal, P< 0.001).

• For 14 hours following exercise, energy expenditure was increased 190 kcal (± 71.4 kcal compared with the rest day, P< 0.001).

• On average this represented approximately 13.6 calories per hour.

• The EPOC represented 37% of the calories expended during the exercise bout.

• Translated into lay terms: o

13.6 calories per hour equals a little over ½ of a Starburst™ candy or 4 M&M™ plain chocolate candies.

o

3,500 kcal = one pound, thus 190 calories = 0.05 lb. or 1/20th of a pound.

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However, if performed 3 times per week, 52 times a year, the EPOC total equals 29,640 kcal (8½ pounds).

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Conclusions and Takeaways

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Conclusions and Takeaways •

In general EPOC generates approximately 7% of the total energy expenditure of exercise. For example, as the average adult expends between 250 and 300 calories in a workout session, EPOC only produce approximately 17½ – 21 calories.

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The cumulative effect of the EPOC over a 1-year period may be the energy expenditure equivalent of 3 pounds of adipose tissue.

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