Excess post-exercise oxygen consumption (EPOC)

Excess post-exercise oxygen consumption (EPOC) is the oxygen used above resting levels after exercise to restore the body’s pre-exercise condition.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 52.} Once called oxygen debt, it can last for hours.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 52.},^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 73.} It includes replenishing oxygen in blood and muscle, resynthesizing ATP and creatine phosphate, and the costs of higher temperature, circulation and ventilation.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 73.} Increased fat cycling, protein turnover and changes in recovery efficiency also contribute.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 73.}

The oxygen deficit at the start of exercise may influence EPOC’s size, but the two are only loosely related and aren’t equal.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 52.}

In practice

• Intensity has the biggest effect: the largest EPOC values come from sessions that are both hard, above about 50% to 60% of VO2 max, and long, over 40 minutes.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 73.} Brief repeated bouts above VO2 max may produce the largest EPOC for less total work.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 73.}
• Heavy sets to exhaustion at 80% to 90% of one-rep max produce a bigger EPOC than circuit training at 50%.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 73.}
• Clients can respond differently to the same relative workload.^{2Haff and Triplett (eds.), Essentials of Strength Training and Conditioning, 4th ed., p. 73.}
• Keep the “afterburn” in proportion: high-intensity work gives a small but significant short-term rise in metabolic rate that low-intensity work doesn’t.^{3Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 58.} Helms and colleagues still recommend creating most of the calorie deficit for fat loss through diet rather than cardio of any intensity.^{3Helms et al., The Muscle & Strength Pyramid: Nutrition, 2nd ed., p. 58.}