You probably already know that resting heart rate (RHR) is the number of times your heart beats or squeezes in the absence of exertion. You might also know that, generally, the fewer beats your heart makes during periods when you’re awake and relaxed, the better. But beyond that, it’s probably not something you think a whole lot about.

According to Allan S. Stewart, MD, Director of Aortic Surgery and Co-Director of the Valve Center in the Department of Cardiothoracic Surgery at The Mount Sinai Hospital, your resting heart rate is worth paying attention to for the myriad of ways it can be an indicator of your overall health. Here’s the nitty gritty on this little number.

There’s no better time to calculate resting heart rate than after rest. Check your RHR just before you hop out of bed in the morning, right after a good night’s sleep—you can do this manually if your Fitbit tracker doesn’t offer PurePulse heart rate tracking. “The easiest place to feel your heartbeat is on the wrist or the neck,” says Stewart. “Simply counting the number of beats for a minute to give you the number.” For kids over age 10 and adults, the normal heart rate is 60 to 100 beats per minute (bpm). Endurance athletes tend to have lower resting heart rates, with numbers ranging from around 40 to 60 bpm.

If your resting heart rate is on the high side, closer to 100 bpm, “you may just be deconditioned,” says Stewart. Yes, that means “out of shape.” That high number is your body hinting that you might want to start an exercise program. Continue tracking your RHR every morning (manually or in your Fitbit app dashboard) as you start working out more frequently—and you should begin to notice a downward trend. “It is exciting and infectious to notice the lowering of your heart rate with each passing week of physical exercise,” Stewart says.

There is no magical exercise to reduce your RHR quickly, so Stewart says to choose some endurance exercises that sounds appealing. “Swimming, cycling, jogging, walking and elliptical are all good choices for heart health,” he explains. “You want 30 or 40 minutes of heart-elevating exercise at least four days a week to start.” Ideally, you want to reach 50% of your maximum heart rate with each workout, which you can find by subtracting your age from 220 bpm. So for a 40-year-old woman, that’s 180bpm. Half that value, 90bpm, should be your goal heart rate while exercising. (You’ll see this noted as your Cardio Zone on your PurePulse-equipped Fitbit tracker and in your dashboard on the Fitbit app.) You should always check with your doctor before starting any new exercise regimen to make sure it’s safe for you.

Exercise can naturally result in a much higher heart rate, but there are some instances in which caution should be taken as you ramp up a new fitness routine. Seniors especially should pay attention to high heart rates with shortness of breath and fluttery or jumpy feelings in the chest during activity. “This may be due to a thickening of the valve that sits between the pumping portion of the heart and the tube that carries blood to the rest of the body,” Stewart says. “The so-called aortic valve is like a thumb on a garden hose. As you tighten that pressure, the heart must work harder for blood to come out.” Another possible reason for a high heart rate is an arrhythmia, most commonly atrial fibrillation. “This condition means that the electrical system of the heart has gone a bit haywire,” Stewart explains. “The result is that the top of the heart is not properly communicating with the bottom of the heart. Your heart rate at rest may jump to 150 to 180 bpm and you may feel palpitations.” These symptoms could require a visit to the doctor.

Many people dislike exercise for one simple reason: It’s hard! But when you set a goal to get moving, thankfully, you should see some really awesome effects. “You will notice improved endurance and easier breathing with exertion,” Stewart says. “More importantly, the effect will continue to support itself; as your resting heart rate becomes lower, your endurance will increase, and you will welcome routine exercise.” Isn’t that cool? Easier exercise means you’ll want to keep it up. You may lose weight, notice more energy, and “the whole cycle will empower you to continue with the process,” says Stewart. “A lower resting heart rate will diminish the stress on your valves, reduce the strain on the heart muscle, lower your blood pressure, and reduce coronary artery disease.”

The end result is a healthier you “that will live longer and live better,” says Stewart—all because you sought to lower your RHR. Pretty cool, right?