Before the rise in popularity of fitness trackers and smartwatches, cardiologist Sadiya Khan said patients rarely came in with questions about why their heart rates seemed high or low. But the growing interest in wearable devices, which some early research suggests can even detect coronavirus symptoms, means many people have a trove of real-time health information at their fingertips.
“I see a lot more people asking about heart rate because you can track it, you can monitor it, you can make pretty graphs on your Apple Watch,” said Khan, an assistant professor of medicine at Northwestern University’s Feinberg School of Medicine.
But while your heart rate can be a key indicator of your health, Khan and other experts emphasized that it is just “one piece of the puzzle.”
“It’s a place to start,” said Seth Martin, a cardiologist and associate professor of medicine at Johns Hopkins. “If that’s your entry into thinking about one’s health, then that’s great.” But your heart rate can’t tell you everything you need to know about your health, he added, and it is important not to fixate on that one measure.
What your heart rate can signal
During cardiac assessments, experts often take into account resting heart rate, how quickly it increases during physical activity, heart rate recovery and heart rate variability, said Daniel Cantillon, the associate section head of cardiac electrophysiology and pacing at the Cleveland Clinic.
For most people, it is considered normal to have a resting heart rate – when the heart is pumping the lowest amount of blood you need – between 60 and 100 beats per minute, according to the American Heart Association. Generally, a lower resting heart rate is associated with higher cardiovascular fitness. Some athletes, for instance, have resting heart rates well below 60.
“A low resting heart rate can indicate a heart that’s physically fit,” Martin said. “If your heart’s in good shape, with each beat of the heart then you’re pumping blood efficiently to the rest of your body.”
If, on the other hand, a person at rest has a high heart rate, “that indicates that the heart’s working harder than we would expect it to have to work at that state,” he said.
How fast your heart rate starts to climb while you are exercising and how long it takes to return to baseline once you are at rest also can be signs of physical fitness, Cantillon said. People who are very fit will have heart rates that accelerate more slowly, whereas sedentary individuals may see their heart rates go up faster and feel out of breath even with lower levels of exertion. Additionally, if you’re less fit, it may take longer for your heart to slow down after exercise, Cantillon said.
Another marker that can be tracked with technology is heart rate variability, or a measure of the variation in time between each heartbeat. A fair amount of heart rate variability, Cantillon noted, can indicate a healthy autonomic nervous system.
“What it means is that in response to things that you’re doing in your everyday life, getting up, taking a shower, brushing your teeth, going to work, doing some exercise, going to bed at night, your body’s nervous system is able to appropriately accelerate and decelerate your heart rate so that it’s situationally matched to what you’re doing,” he said.
How to monitor your heart rate
Outside of directions from a physician, how often you want to check your heart rate is an individual choice that largely depends on how useful the information is to you, experts said.
Rather than focusing on the fixed heart rate number at a specific moment, it may be better to keep track of trends and observe how your heart rate is changing, said Thomas Allison, director of the Sports Cardiology Clinic at the Mayo Clinic in Rochester, Minn.
“If you see rather persistent trends in your heart rate up or down, or you see sudden change, that might be of concern,” he said, “particularly if you’re not feeling well.”
It may also be helpful to monitor your heart rate if you’re starting a new fitness program to gauge improvement and make sure you aren’t overdoing it, Allison said. “We know that with training, with cardiovascular conditioning, your heart rate gets slower, and so you can track your improvement there,” he said. “If you’re over training and working too hard and not getting enough rest, you might see the heart rate drift back up again.”
During exercise, Khan said she encourages people to get their heart rate up to at least 50% of their estimated maximum heart rate, which is 220 minus your age.
But don’t obsess over your heart rate, Allison said. “It may give you a false degree of concern or a false sense of security,” he said.
Cantillon added that he has had patients who get access to wearable technology and “unfortunately, they kind of go off the deep end.” They tend to overinterpret data, which triggers anxiety about what they think is happening to them, he said. “We do a fair amount of reassurance.”
If you’re monitoring your heart rate, consistency is key and experts widely recommend taking your resting heart rate in the morning shortly after waking up. Recording your heart rate at the same time allows for more precise day-to-day comparisons.
You can accurately check your pulse without technology using the traditional two-finger approach and counting your heart beats. The advantage of wearable devices is that they can record and store information so that it is easily accessible, Cantillon said, noting that you need to make sure you’re wearing them according to the manufacturer’s instructions.
But although most wearables reliably collect accurate data at rest, the quality can become variable during physical activity, said Martin, who suggested using a chest strap device for workouts if you really want a more precise reading. A paper published online in 2016 in JAMA Cardiologyfound that wrist-worn technology wasn’t as accurate as a chest strap-based monitor. “In general, accuracy of wrist-worn monitors was best at rest and diminished with exercise,” the researchers wrote.
How to think about your heart rate
“Heart rate’s not useless as a measure of health, but it’s not a very precise measure of health,” Allison said. Your heart rate can be affected by many factors, including age, medication, stress levels, sleep, physical activity, diet and hydration.
Consider this example: “A heart rate less than 60 is great if it’s achieved by being fit,” Allison said. But it would be a problem if you have an underlying medical condition that’s causing your heart to beat more slowly.
Similarly, he said, an elevated heart rate could be a triggered by something benign, such as excitement, or it could be your body signaling that you might be coming down with an illness, such as COVID-19.
The experts advise talking to your primary care provider if your heart rate is consistently higher or lower than expected. But if dramatic changes in your heart rate are accompanied by symptoms such as palpitations, chest pain, fatigue, lightheadedness, dizziness or shortness of breath, you should seek medical care. “The more persistent the symptoms are, the faster you need attention,” Allison said.
One thing you shouldn’t do: measure your heart rate against others’. “If you’re comparing, ‘Oh, my heart rate’s two beats lower than yours, so I’m healthier. I’m going to live longer – well, no,’ ” Allison said.
Instead of specifically trying to improve your heart rate, experts suggested taking a more holistic approach to health. “The focus needs to go back to all of the things that we know are good for cardiovascular and overall health,” such as regular exercise and a heart healthy diet, Khan said.
Allison agreed. “We have to remember that maintaining good health is about behaviors,” he said, “not taking tests.”