Why do exercise needs vary between individuals?

It depends on the way you eat, and what your overall fitness goal is. Males often need more exercise than Females.

It depends on how u eat and how much energy you have and whether you are a male or female.

Explanation:

the more fit you are, the faster the recovery. your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. this “recovery heart rate” is measured as part of an exercise stress test.