Final answer:
The relationship between exercise intensity and time duration is that the amount of energy used during exercise, or the power level, is directly related to the duration of the activity.
Step-by-step explanation:
The relationship between exercise intensity and time duration is that the amount of energy used during exercise, or the power level, is directly related to the duration of the activity. When engaging in low intensity or skill-based activities, the duration of exercise may be shorter. For a moderate exercise program, which typically lasts about 1 hour per day, the intensity is moderate. And for an endurance program, which involves moderate to high intensity exercise, the duration may be longer, ranging from 1 to 3 hours per day.