Why Athletes Tend to Have a Lower Resting Heart Rate

Resting heart rate as a baseline metric will guide everything you do to improve your fitness. And it's trainable.

By Ashley Mateo |

Wearable fitness technology has provided cyclists of all levels with an overabundance of numbers that can inform their performance. But one data point in particular—heart rate—has been a staple in training for decades.

Whether you use heart rate training to boost your bike performance or barely understand how to calculate your max heart rate, understanding your resting heart rate can help you get more out of every ride—and give you better insights into your overall health.

What is resting heart rate and what should it be?

Your resting heart rate (or RHR) is the number of times your heart beats per minute when you’re at rest. The best time to calculate it is first thing in the morning, before you get out of bed and start moving around, says Tom Holland, an exercise physiologist, certified strength and conditioning specialist, and certified sports nutritionist.

You can measure RHR the old-school way: Lightly press your index and middle fingers to the opposite wrist, just below the base of the thumb, counting the number of beats in 15 seconds, and multiplying that by four. Or, you can use a fitness tracker. FWIW, you’re going to get the best results with a chest strap, says Holland, although wrist-based heart rate monitors accurately measured up to 89 percent of heart beats at rest, according to a 2017 paper presented at the European Medical and Biological Engineering Conference.

When it comes to resting heart rate, “the number that you’ll see over and over is 60 to 100, so it’s a pretty wide range,” says Eli Friedman, M.D., medical director of sports cardiology at Baptist Health’s Miami Cardiac & Vascular Institute. In the medical world, a resting heart rate faster than 100 beats per minutes is known as tachycardia, while a resting heart rate slower than 60 beats per minute is considered bradycardia, he adds. (Keep in mind that high and low resting heart rates might have medical names, but that doesn’t always mean you need to address the issue.)

It’s totally normal for athletes—people who engage in exercise at higher volumes and higher intensities—to have lower heart rates, Friedman says. He often sets resting heart rates to between 30 and 50 bpm, which is where many athletes fall. An athlete’s resting heart rate is usually only considered too low when they’re experiencing symptoms like fatigue, dizziness, and weakness.

If your resting heart rate is high and you experience symptoms like shortness of breath, dizziness, weakness, or chest pain, then it’s time to see a doctor, according to the Mayo Clinic.

Why does resting heart rate matter for athletes?

A low resting heart rate is a hallmark of cardiovascular fitness and efficiency, says Friedman. On the flip side, a higher resting heart rate has been associated with a higher risk of cardiac events like strokes and heart attacks.

“When you engage in exercise, your heart rate speeds up so it’s able to feed all the various muscles and organ systems at work with enough blood,” Friedman explains. That’s a good thing! Your heart is a muscle, and it’s subject to the rules of hypertrophy—a.k.a. an increase in muscular size achieved through exercise—just like your quads or calves. Keep stressing it through exercise, and it’ll keep getting stronger.

“The stronger your heart muscle is, the more blood it can pump out with every contraction,” Holland explains. When the amount of blood ejected with each heart stroke (a.k.a. stroke volume) increases, the heart can beat less while still supplying the same amount of blood to the body.

Here’s how that stronger heart muscle and increased stroke volume pays off in your workouts: During exercise, your heart rate will be lower at given intensities, says Holland. That means you’ll be able to produce more output, or watts, at a lower effort level. Instead of feeling like you’re going to die a quarter of the way up a hill, you might not start huffing and puffing until you’re three-quarters of the way there.

Plus, if you’re pumping out more blood with each contraction of the heart muscle, that means you’re delivering more oxygen and nutrients to the muscles with every heartbeat (in addition to removing carbon dioxide and other metabolic waste products from the cells), says Holland—another factor that contributes to efficiency.

In other words, the more you train your cardiovascular system, the lower your heart rate will become during similar efforts so you can continue to go longer or faster.

Can you lower your resting heart rate?

Yes, to an extent. Your resting heart rate is affected by your age, gender, health issues (like diabetes or high cholesterol), medications, fitness and activity levels, emotions, and even external conditions (like altitude or temperature). It’s totally normal for it to fluctuate to some degree.

The number one way to lower your resting heart rate is exercise. But don’t think of it as a goal of exercise, rather a byproduct: The fitter you get, the lower your resting heart rate will get.

Varying your workouts is important for that lower heart rate. “Endurance training helps your body develop greater capillary density [the number of capillaries in a certain area of muscle] and increases the number and density of mitochondria [the powerhouse of your cells, where fuel is turned into energy],” says Holland. But interval training, where you’re getting close to your max heart rate, stresses your body to the point where it must adapt (read: get stronger), says Friedman.

If you’re already hitting the recommended physical activity guidelines and your heart rate is still high, then you might need to look into lifestyle changes. (Those guidelines mean you hit 150 to 300 minutes a week of moderate-intensity physical activity or 75 to 150 minutes a week of vigorous-intensity physical activity, or an equivalent combination of the two.)

Stress can be a major reason for a higher resting heart rate, because it triggers your body’s “fight or flight” response. Chronic stress, which keeps your system flooded with cortisol, has been linked to increased cardiovascular events, so managing stress is a crucial part of heart health.

Stimulants like caffeine, alcohol, and tobacco can also drive your heart rate up, says Friedman. If you have concerns about your resting heart rate, minimising those or cutting them out entirely could lead to big changes.

Staying hydrated is also important, says Friedman; when you’re dehydrated, your blood thickens, which means your heart has to work harder to pump it out. And, of course, you should prioritise a good night’s sleep: Even short-term sleep deprivation can lead to a significant increase in heart rate, research presented at the 2016 annual meeting of the Radiological Society of North America found.

The good news: You should be doing all of these things already, because they’re the tenets of healthy living. And, if you’re not, you can start to implement small changes—say, cutting back on the number of drinks you have per week, or going to bed an hour earlier each night.

Just remember that the occasional spike in resting heart rate isn’t cause for alarm. Your resting heart rate is a baseline measurement, and it can be affected by a number of things on a day-to-day basis.

The key with any health metric—especially those you’re tracking via wearable technology—is paying attention to patterns. “Once you start getting multiple data points (from checking your resting heart rate every morning),” says Holland, “you can figure out what’s normal for you and when something is out of that norm.”

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