Athletes typically have a lower resting heart rate than the general population, a common adaptation to consistent endurance training.
As the cardiovascular system becomes more efficient, the heart can pump more blood with each beat, meaning it doesn’t need to beat as often to meet the body’s needs at rest.
For many runners and well-trained athletes, seeing resting values in the 40s or 50s can be completely normal, and in some cases, highly trained endurance athletes may dip into the 30s, especially overnight.
Still, resting heart rate lies on a spectrum and is influenced by factors beyond fitness alone, including genetics, recovery status, stress, hydration, sleep, illness, medications, and overall health.
In this guide, we’ll explain why resting heart rate tends to be lower in trained athletes, what can cause an unusually high resting heart rate even in fit runners, and how to measure your resting heart rate accurately so you can use it as a practical indicator of recovery and training readiness.
Why Do Athletes Have a Lower Resting Heart Rate?
The heart is a muscle, and like other muscles in the body, it gets stronger with consistent training. Regular aerobic exercise strengthens the heart and lungs.
As the heart gets stronger, it can contract more forcefully with each beat.
When the heart contracts more forcefully, the stroke volume increases, meaning it can pump more blood—and thus more oxygen—out to the rest of the body with each heartbeat.
This means that an athlete’s heart rate at rest is lower than that of an untrained adult because the heart has become more efficient.
There are also indirect ways that regular exercise helps lower an athlete’s resting heart rate.
For example, aerobic exercise helps increase the elasticity of blood vessels, making them more extensible and pliant. This helps reduce blood pressure because the heart encounters less peripheral resistance to blood flow.
As blood vessel elasticity increases, blood pressure decreases, and resting heart rate decreases because the heart can pump blood into circulation with less effort.
Additionally, regular aerobic exercise improves the strength and efficiency of the lungs.
Much in the way that a stronger heart has a higher stroke volume, stronger lungs have a greater tidal volume, which refers to the amount of air inhaled per breath.
The lungs become more efficient at taking in more oxygen per breath.
This, in turn, can lower athletes’ resting heart rate because the lungs and diaphragm do not need to work as hard at rest to take in enough oxygen for the body, reducing the workload on the heart to oxygenate and fuel the lungs and diaphragm.
Finally, another significant factor that indirectly reduces athletes’ average resting heart rate is that their muscles become more efficient at using oxygen.
During exercise and at rest, the muscles are one of the primary consumers of oxygen and the driver of a higher heart rate, enabling the heart to deliver enough oxygenated blood to the muscles.
Endurance training increases both capillary density and mitochondrial density in the muscles, improving the delivery, extraction, and utilization of oxygen for aerobic energy production.
This not only helps decrease your heart rate at various submaximal exercise intensities but can also lower your resting heart rate.
If the muscles are better perfused with oxygenated blood due to more capillaries, they can take up more oxygen every time the heart beats.
Then, because aerobic training increases mitochondrial density in skeletal muscles (mitochondria are small organelles or specialized structures in muscles that help convert glucose, glycogen, or fat into ATP (usable energy)), the oxygen taken up by the muscle can be used immediately.
To this end, as muscles become stronger through consistent exercise, the relative demand for oxygen decreases at rest because the muscles are accustomed to much higher workloads.
Essentially, regular aerobic exercise:
- Improves the efficiency and health of the cardiovascular system
- Strengthens the heart muscle directly
- Decreases blood pressure
- Strengthens the lungs and diaphragm
- Increases the elasticity of the blood vessels
- Builds new capillaries and mitochondria
- Decreases the oxygen needs of muscles at rest
Thus, the average resting heart rate of a fit individual is lower than that of an untrained adult.
Average Athlete Resting Heart Rate vs Normal Resting Heart Rate
According to the American Heart Association, the normal resting heart rate for adults is typically between 60 and 100 beats per minute, though it tends to be lower in runners and other endurance athletes due to physiological adaptations from consistent training.1American Heart Association. (2024, May 13). All about Heart Rate. American Heart Association; American Heart Association. https://www.heart.org/en/health-topics/high-blood-pressure/the-facts-about-high-blood-pressure/all-about-heart-rate-pulse
According to Dr. Deepak L. Bhatt, MD, MPH, at Harvard Health, athletes sometimes have resting heart rates below 40 beats per minute due to positive adaptations to exercise.
On the other hand, a resting heart rate below 60 bpm in sedentary individuals can be a sign of an electrical problem with the heart, hypothyroidism, heart disease, or damage from a heart attack.
According to The Baker Heart & Diabetes Institute, bradycardia in athletes (a resting heart rate below 60 bpm) is generally considered a healthy adaptation to exercise.
However, not all cases of bradycardia are benign.
Bradycardia, or a very low resting heart rate in athletes, has been associated with an increased risk of developing atrial fibrillation, which is a heart arrhythmia that is known to increase the risk of stroke, heart failure, and even death.
Overall, although there can be a range, athletes tend to have a resting heart rate below 60 bpm, so if you are a fit individual and your heart rate is slower than 60 bpm, it is likely not a cause for concern.
Can An Athlete’s Resting Heart Rate Be High?
While the general trend is that the typical resting heart rate of athletes is lower than that of sedentary or relatively inactive adults, some athletes have a high resting heart rate.
There are various factors that can cause a high resting heart rate in athletes.
For example, if you are dehydrated, under chronic or acute stress, or in a warm climate, your resting heart rate may be higher than normal, even if you are a fit athlete who normally has a low resting heart rate.
Furthermore, another common problem that can cause a high resting heart rate in athletes is poor recovery or overtraining.
A sudden increase in your normal resting heart rate can also be a sign that you’re getting sick and your heart is working harder to stave off illness.
With this in mind, monitoring resting heart rate can be a valuable practice for athletes and can provide a window into your training status and the potential need for more rest.
If you do have concerns about your resting heart rate being too low, you should speak with your healthcare provider.
Tips for Measuring Resting Heart Rate
In most cases, it is best to take your resting heart rate level immediately upon waking up in the morning before you get up and start moving around or introduce caffeine, stress, or exercise into your day.
Any of these factors will stimulate your autonomic nervous system, which controls your heart rate.
Therefore, in order to get a true resting heart rate, you want your body to be relaxed and still, having rested for several hours.
Your heart rate changes throughout the day based on a number of factors, the primary one being your activity level.
For example, your resting heart rate will be much lower than your heart rate during a brisk walk, strength training workout, climbing the stairs, or a trail run because the cardiovascular demand during physical activity is much higher than it is at rest.
Your resting heart rate should be low because when you are lying down and in a calm and relaxed state, your muscles, tissues, and heart need much less oxygen—and thus less blood (since blood carries oxygen)—than they do when you are exercising.
Therefore, your heart does not need to contract as frequently or forcefully in order to pump enough blood and oxygen around your body while still meeting the needs of your muscles and tissues.
This means that your resting heart rate is lower than your exercise heart rate.
To learn more about the benefits of regular exercise, check out our next guide:
