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One of the quickest, easiest ways to gauge your heart health is to check your resting heart rate (RHR). Considered as context for a slew of other markers—like blood pressure, stress, and sleep deprivation—heart rate typically lowers at rest compared to when you’re doing just about any activity, and it varies from person to person. Since one in every four deaths in the United States—about 610,000 people annually—occurs as a result of heart disease, it’s important to be in the know about yours.
So, it’s also important to know what a low resting heart rate is, and if yours is something to be concerned about.
How low is too low for a resting heart rate?
“Generally speaking, a person’s resting heart rate is normal if it’s between 60 and 100 beats per minute,” says Dr. Brian Mikolasko of Brigham and Women’s Hospital in Boston. “There are a ton of different factors that play into what it is for each individual, from fitness level to age and environment.”
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The standard resting heart rate window actually varies the most in young children. Up to 1 month, heart rate ranges from 70 to 190 beats per minute. The upper limit of that range declines slowly until age 9, when the range is sits between 70 and 110 beats per minute. From 10 years old and beyond, the window sits constant between 60 and 100 beats per minute.
Whereas a resting heart rate of 42 or even 38 beats per minute can be typical for a well-trained endurance runner or triathlete, that would be pretty low for someone who is a casual exerciser. Best measured before you start moving around first thing in the morning, a resting heart rate is much different than what you’ll see during exercise.
The American Heart Association (AHA) states that the maximum heart rate during exercise should be roughly equal to 220 bpm minus the age of the person, which is one very basic method to estimate your max. Age-based equations are straightforward and easy to use, but they may not be a good fit for everybody because there are too many factors that can affect their accuracy. Plus, max heart rate varies significantly among people of the same age. That’s why the American College of Sports Medicine suggests age-based formulas with a lower standard deviation, for example, the Gelish equation: 207 – (0.7 x age) or Tanaka: 208 – (0.7 x age).
Because the normal range of a resting heart rate is between 60 to 100 bpm, a resting heart rate under 60 beats per minute is considered slow, often referred to as bradycardia.
“It is not unusual for healthy people involved in endurance activities to develop a bradycardia based on the increased vagal tone from training that suppresses heart rate,” says William O. Roberts, M.D., a professor in the Department of Family Medicine and Community Health at the University of Minnesota.
“Training also increases the heart size so it can push out a greater volume of blood to the body with each contraction.” Roberts explains that a lower heart rate will deliver the same blood volume in a trained resting heart as the higher heart rate in an untrained heart. Plus, detraining or stopping regular endurance exercise will reverse both effects, so a runner taken out of commission by illness or injury will have to regain the changes with training after recovery, he says.
When should I go see a doctor?
If you’re concerned your low resting heart rate is too low, you should contact your doctor. Mikolasko recommends checking in with a physician if your resting heart rate sits below 60 beats per minute consistently, just to be safe. “This is definitely something you can cover with your physician during your annual physical, and they may tell you it’s nothing to be concerned about,” he says. “But it’s certainly better to be safe than sorry.”
Remember, these things can also hinge on other situational factors. It’s common for well-trained people to feel a bit lightheaded when moving quickly from a squat to stand, according to Roberts. Reaching to the floor or squatting for any length of time? Then you may find you have to stand still for a moment to let the blood reach your brain.
If you experience symptoms such as irregular heart beat, dizziness, lightheadedness, chest pain, blacking out, shortness of breath, or generalized weakness, you should check in with a doctor, STAT.
Heart-Rate Training Helpers
Fitbit Fitbit Versa 3 Smartwatch
Polar Vantage V2
Garmin HRM-Tri Heart Rate Monitor
Emily Abbate is a freelance writer, certified fitness trainer, and host of the podcast Hurdle. You can find her work in GQ, Shape, Runner’s World, and other health and fitness publications.
