Glossary: EPOC (excess post-exercise oxygen consumption)

What EPOC is

After exercise, your oxygen consumption stays elevated above resting baseline for some period. The total extra oxygen used during that recovery window is EPOC. Sometimes called the "after-burn" effect.

EPOC reflects:

• Replenishment of phosphocreatine stores.
• Restoration of myoglobin and hemoglobin oxygen.
• Re-warming or cooling to homeostasis.
• Elevated catecholamines / metabolic rate.
• Lactate clearance.

Typical magnitude

• Moderate aerobic workout (1 hour at Z2): EPOC adds 10 to 30 extra calories burned in the hours after.
• Hard interval session (1 hour VO2 work): EPOC adds 100 to 200 extra calories.
• Long hard race (4+ hours, threshold-paced): EPOC can extend for 24 to 48 hours and add several hundred calories.

What EPOC is sometimes mistaken for

The "after-burn" effect is real but typically modest. For weight management, the calories burned during the workout dominate; EPOC is a small bonus, not a free-calories generator.

The marketing claim that "HIIT burns calories all day" is overstated. The HIIT session itself burns most of the total; EPOC adds a small percentage.

What the Hub does with EPOC

The Hub does not capture EPOC directly. The fueling planner includes a post-race recovery window in its plan, reflecting elevated metabolic state.

Garmin and some other devices report EPOC estimates per activity. If your FIT file carries that value, it imports to the Activity record but is not used as a primary metric.

Practical takeaway

• Recovery from a hard session needs fuel, both for the session itself and for EPOC. Eating in the 1 to 3 hours post-session matters.
• EPOC is not a reason to train harder. Train at the right intensity for the goal; EPOC follows.

See also: Fueling planner, Glossary: aerobic vs anaerobic.