jebmo’s posthaven

You probably learned how to track your heart rate in school: Put your finger on a pulse point, like the inside of your wrist, and count how many pulses you feel in a minute. That yields your heart’s beats per minute, or bpm. Cool trick! you thought. And you promptly forgot about it.

But your heart rate can be a useful piece of data. It’s a reliable metric for setting fitness goals that puts your cardiovascular health—ahem—at the heart of your workout. Plus, maintaining a healthy heart rate can reduce your risk of strokes, heart disease, and cardiac arrest.

If you have a wrist-worn activity tracker, it’s dead simple to monitor your heart rate accurately and continuously. Here's how to use that data to keep your ticker in top shape.

Listen to Your Heart

From the moment you strap on a Fitbit or an Apple Watch, you'll start seeing your bpm on the screen. But what do those numbers mean?

“It’s important to understand that there is a spectrum of what constitutes a normal heart rate,” says Dr. Gregory Marcus, Director of Clinical Research for the Department of Cardiology at the University of California, San Francisco. He's also part of the research team for the Health eHeart Study, which aims to shed light on heart disease by analyzing digital health data from participants' mobile health-tracking devices.

You might have heard that a healthy resting heart rate—the rate when you’re physically and mentally relaxed—typically falls between 60 and 100 bpm. But Dr. Marcus explains that it’s not so simple, since heart rates vary from person to person.

“In many cases, the more fit a given individual is, the more their heart rate will slow while they’re at rest or while they’re asleep,” says Dr. Marcus. So a person who is very athletic might find that their resting heart rate slows to 30, even 20 bpm. This is because the heart muscle of a physically fit person doesn’t have to strain as much to support the body’s needs.

Your heart rate can also fluctuate widely throughout the day. So if your chest is pounding during a workout, your heart is pumping more oxygen-rich blood to support your physical exertion. Conversely, when you’re lounging on the couch, your heart rate might slow substantially. Your heart rate can also vary depending on your level of stress, if you’re pregnant, or if you’ve just downed a cup of coffee.

Dr. Marcus says that “in general, there isn’t really a heart rate that raises the concern of a cardiologist,” unless those perceived abnormalities in heart rate co-occur with more obvious symptoms. In other words: While it’s good to be mindful of your heart rate, don’t stress out too much. You may, ironically, raise your heart rate worrying about it, and that’s not healthy by any measure.

Take Measurement

Your heart rate is a convenient, objective way to measure how much you’re exerting yourself during a workout. Using the heart rate data from your activity tracker, you can inform and adapt your exercise regimen.

Start by determining your target heart rate. This is the heart rate that you should seek to achieve and maintain during rigorous exercise. Dr. Marcus advises collaborating with a physician or a trainer to determine your target heart rate and the duration for which you should aim to maintain it during a workout.

The American Heart Association offers some rough guidelines for setting your target heart rate. First, calculate the average maximum heart rate for someone your age. You can do this by subtracting your age from 220. So the average maximum heart rate for a 30-year-old would be around 190 bpm. Your target heart rate can be anywhere between 50 and 85 percent of your maximum heart rate. Depending on whether you’re easing back into a workout routine, or if you’ve been training regularly, you can set incremental goals to increase your progress toward your target heart rate.

During your workout, all you need to do is glance at your wearable tracker. You can also check your data afterward. Wearables like Garmin, Fitbit, and Apple Watches have compatible apps that graph your heart rate over time. You can easily see your bpm and have a concrete idea of the intensity of your workout.

Get the Right Fit

You can’t get an accurate read on your heart rate unless your device is charged, functional, and fitted properly. Make sure your wearable fits snugly around your wrist to ensure that it picks up your pulse during your workout.

Be mindful that some wearables give more accurate heart rate readings than others. While wrist wearables are for the most part precise enough for everyday use, chest wearables give the most exact readings. Some devices’ ability to pick up heart rates is compromised when you’re working out in the water, and others aren’t waterproof at all. For accurate heart rate readings, our own reviewer swears by Garmin’s wrist wearables.

Finally, remember not to focus so much on the numbers as much as the quality of your exercise. Use your heart rate data as a motivator—so you can run, dance, swim, and bike your way to a healthier heart.