When you perform aerobic exercise, less than one-third of the calories you burn during the activity result in a lasting increase in your total daily calorie burn.

We analyzed the available evidence and found that when you perform aerobic exercise, less than one-third of the calories you burn during the activity lead to a lasting increase in your total daily calorie burn [1]. This means most of the energy you use while running, cycling, or swimming is used only during the workout itself and doesn’t significantly raise your overall daily energy expenditure afterward. What we’ve found so far is based on 60 studies or assertions that all point in the same direction, with none contradicting this pattern. The idea that aerobic exercise creates a big, long-term boost in calorie burn — sometimes called the “afterburn effect” — doesn’t appear to be strongly supported by the evidence we’ve reviewed. Instead, the majority of the calories burned during aerobic activity are accounted for during the time you’re moving, not in the hours after. This doesn’t mean aerobic exercise isn’t useful. It still helps with heart health, endurance, and managing weight by creating a clear calorie deficit during the workout. But if you’re expecting your body to keep burning extra calories long after you stop, the evidence suggests that effect is smaller than many assume. The practical takeaway: Focus on the calories you burn while you’re active, not on a big post-workout boost. If you want to increase your daily energy expenditure over time, combining aerobic exercise with strength training and consistent movement throughout the day may be more effective than relying on afterburn.