Ask Dr. K: Aim for target heart rate range

DEAR DOCTOR K: I’ve seen fitness monitors that track heart rate. Is it important to know your heart rate when you’re exercising?

DEAR READER: Whether you’re just getting started with an exercise routine or are a committed fitness enthusiast, tracking your heart rate can be helpful. Heart rate monitors – which instantly tell you how fast your heart is beating – can help you exercise at the right intensity.

Heart rate monitors worn on the wrist or head track the blood flowing through tiny vessels in your skin. Every time your heart pumps, blood suddenly gets pushed through those vessels. When the heart relaxes, blood flow stops. Heart rate monitors use an optical sensor to “see” blood flowing and stopping. From that, they can tell your heart rate.

A heart rate monitor gives you an accurate way to gauge your effort on a day-to-day basis. This can help ensure you’re exercising hard enough to keep your heart healthy, but not so hard you are putting yourself in danger.

So what should your heart rate be when you’re exercising? For that matter, what is a “normal” resting heart rate?

RESTING HEART RATE: This is your heart rate when you’re most relaxed. Use your heart rate monitor right after you wake up in the morning, or use it during the day when you’re relaxing. Either is your resting heart rate.

MAXIMUM HEART RATE: This is an estimate of the highest heart rate a person could reach while exercising very strenuously. The formula for calculating maximum heart rate is 220 bpm minus your age. Remember, it’s an estimate.

TARGET (OR TRAINING) HEART RATE: This range is 65-80 percent of your maximum heart rate. To get the most health benefit from your exercise, try to stay in your target heart rate range for at least 20 minutes during an exercise session.