# Minimum and maximum heart rate for aerobic exercise

Dear Alice,

I work out on my treadmill 20 to 30 minutes a day, usually one to two miles. My husband says that there is a minimum and maximum heart rate. Is there a formula that I can use to calculate this information? Please advise.

Yes, it's true that there are recommendations for minimum and maximum heart rate during physical activity. There are multiple approaches to calculating an appropriate heart rate range, depending on your current level of fitness and physical activity goals. Being mindful of this number and working out at a target heart rate for your individual body helps to improve cardiovascular and respiratory health.

Before learning how to calculate minimum and maximum heart rate, it's beneficial to understand what these numbers mean. A maximum heart rate is an estimate of the heart rate (beats per minute) that someone potentially could (not should) achieve during maximum physical exertion. Aptly named, the resting heart rate is your heart rate measured during rest — this measurement is best taken in the morning before any stress, caffeine, or movement occurs. These upper and lower limits are used to calculate the target heart rate, or percentage of maximum heart rate reached during physical activity. These days, many people use heart rate monitors built into machines and wristwatches to measure their heart rate. However, the time-tested, most accurate way of measuring your heart rate is by placing your index and middle finger on your carotid artery (windpipe) or on your radial artery (wrist) and counting your pulse for 15 seconds. Then, multiply that number by four to calculate beats per minute.

After measuring your heart rate before, during, and after physical activity, the easiest way to determine a target heart rate range is by subtracting your age from 220 to get your maximum heart rate. Multiply that number by the percent of maximum heart rate you wish to achieve. For moderate physical activity, the goal is usually 50 to 70 percent, while vigorous physical activity often reaches 70 to 85 percent of your maximum heart rate. For example, Devin, a 24-year-old exercising at moderate intensity, would aim to have a heart rate between 98 and 137 beats per minute. HR = (220-24) x 0.5 or 0.7.

A more specific method, often preferred by athletes, is the Heart Rate Reserve (HRR) method. Though similar, this calculation subtracts resting heart rate from maximum heart rate (220-age). Multiply this number by the same percentage goals outlined before and add that amount back to your original resting heart rate. For example, Devin has a resting heart rate of 65 and is now exercising at 60 percent intensity. Therefore, their heart rate goal would be approximately 144 beats per minute. HR = (220-24-65) x 0.6 + 65