How to check your pulse and heart rate Exercise is an important part of cancer prevention. You need 150 minutes of moderate physical activity or 75 minutes of vigorous exercise each week to help lower your cancer risk. Your heart rate can help you determine if the exercise you’re doing is moderate or vigorous. If you’re working at 50 to 70% of your maximum heart rate, then that exercise is considered moderate. If you’re working at 70 to 85% of your heart rate then its vigorous exercise. Learn more: Request an appointment at MD Anderson by calling 1-877-632-6789 or online at: