Fuel Usage During Exercise

The type of substrate (fuel) and the rate at which it is utilized during exercise is largely dependent on the intensity and duration of the exercise. During strenuous exercise there is an obligatory demand for carbohydrate (CHO) oxidation that must be met; fat oxidation cannot substitute. In contrast, there is an increase in fat oxidation during prolonged moderate intensity exercise as carbohydrate fuels are depleted. Fats are also more dominant in long duration exercise since fat oxidation requires more oxygen than does carbohydrate oxidation.

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