Enter your age in years. If your birthday is coming soon, you can round upwards.

Maximum heart rates are higher for men than for women.

To get your resting heart rate, take your pulse before getting out of bed in the morning or after sitting quietly for five minutes. (If you have to guess, use 60 if you're unusually fit, 70 if you're sedentary, 80 if you're unfit or obese.)

Your Target Zone depends partly on the type of exercise you're doing. If yours isn't on the list, choose an activity that seems equally strenuous.

Choose "Novice" if you haven't gotten much aerobic exercise in recent months; "Intermediate" if you've averaged 20 to 40 minutes three to five times a week; "Advanced" if you've averaged significantly more. (Aerobic exercise is any steady activity that raises a sweat and can be performed for many minutes without stopping, such as jogging or swimming. Short-burst activities that leave you out of breath, such as weightlifting, are not aerobic.)