What fuel source is Jan using if she exercises at 85% of her maximum aerobic capacity?

Question

Quizplus · Accepted Answer

When exercising at high intensity (such as 85% of maximum aerobic capacity), the body primarily uses carbohydrate as fuel. Fat is a more efficient fuel source but requires more oxygen and is not able to provide energy as quickly as carbohydrate. Creatine phosphate is used for short bursts of high intensity activity, while protein is not a preferred fuel source for exercise.

What Fuel Source Is Jan Using If She Exercises at 85