Your smartwatch says your resting heart rate is 52 beats per minute.
Is that good?
Does it mean you are incredibly fit?
Should you be concerned?
Or is it simply your normal?
Resting heart rate is one of the easiest physiological measurements to collect, especially now that watches and wearable devices track it around the clock. But having more data does not necessarily mean we understand what the data means.
This is especially true with a low resting heart rate.
You may have heard that a low resting heart rate is a sign of cardiovascular fitness. That can absolutely be true. But a low heart rate is not automatically proof that someone is fit, just as a higher resting heart rate does not tell us everything about a person's health.
The number needs context.
Let's break down what resting heart rate actually represents, what the term bradycardia means, why physically fit people often have lower resting heart rates, and when a low number deserves a closer look.
First, What Is Resting Heart Rate?
Your resting heart rate, or RHR, is simply the number of times your heart beats per minute when your body is at rest.
For most adults, resting heart rate commonly falls somewhere between approximately 60 and 100 beats per minute. A resting heart rate below 60 bpm is often described as bradycardia.
That word can sound intimidating, but it is important to understand what it actually means.
Bradycardia literally describes a slow heart rate. It does not automatically mean something is wrong with your heart.
Someone with a resting heart rate of 55 bpm may be perfectly healthy. Someone else with the same heart rate may need further evaluation.
The difference is not simply the number.
It is the entire picture surrounding that number.
What Does “Sinus Bradycardia” Mean?
You may also hear the term sinus bradycardia.
The sinus node is essentially the heart's natural pacemaker. It generates the electrical signal that initiates each heartbeat.
When your heart is beating normally from the sinus node but simply doing so at a slower rate, it may be described as sinus bradycardia.
For a healthy, physically active person, this can be completely normal.
In fact, lower resting heart rates are extremely common among endurance-trained individuals. In a recent study of national-level triathletes, the athletes had an average resting heart rate of approximately 54 bpm compared with 72 bpm in sedentary controls, and sinus bradycardia was observed in more than two-thirds of the athletes (Climstein et al., 2025).
That does not mean everyone should try to get their resting heart rate into the 40s or 50s.
It simply demonstrates that a slower heart rate can be a normal physiological adaptation to training.
Why Does Exercise Often Lower Resting Heart Rate?
Think of the heart as a pump.
Every time the heart contracts, it sends a certain amount of blood into circulation. The amount of blood pumped with each beat is called stroke volume.
With consistent aerobic training, the cardiovascular system becomes more efficient. Among other adaptations, the heart can generally pump more blood with each contraction.
If more blood can be delivered with every heartbeat, the heart may not need to beat as frequently at rest to maintain the necessary cardiac output.
Training also influences the autonomic nervous system—the balance between the sympathetic "fight-or-flight" system and the parasympathetic "rest-and-recover" system—which contributes to changes in resting heart rate.
A large systematic review examining 191 exercise studies found that regular exercise tended to reduce resting heart rate, with endurance training showing particularly consistent reductions (Reimers et al., 2018).
So if your resting heart rate gradually moves from 68 to 62 to 57 over months of consistent aerobic training while your fitness and exercise tolerance are improving, that change may reflect positive cardiovascular adaptation.
But there is an important distinction:
A lower resting heart rate can be a consequence of improved fitness. It should not necessarily be the goal of your training.
You do not train simply to see how low you can push the number on your watch.
Resting Heart Rate Can Tell Us Something About Fitness
Resting heart rate and cardiorespiratory fitness are related, but they are not interchangeable.
A large 2023 investigation from the Fenland Study examined more than 10,000 adults between 29 and 65 years old and found that higher cardiorespiratory fitness was associated with lower resting heart rates. Researchers also followed more than 6,500 participants over approximately six years and found that increases in resting heart rate were associated with decreases in estimated fitness (Gonzales et al., 2023).
That makes resting heart rate potentially useful as part of your overall performance dashboard.
But notice the wording: part of the dashboard.
Resting heart rate does not replace a VO₂ max assessment. It does not tell us your blood pressure, cholesterol, glucose control, body composition, muscular strength, sleep quality, recovery status, or cardiovascular disease risk.
Two people can have identical resting heart rates and dramatically different health profiles.
This is one of the reasons I encourage people to stop thinking about individual health measurements as grades.
A resting heart rate of 52 is not automatically an "A."
A resting heart rate of 72 is not automatically a "C."
The number becomes useful when we understand what is driving it.
Is Lower Always Better?
This is where the conversation gets particularly interesting.
Across large populations, higher resting heart rates have consistently been associated with greater health risk.
A meta-analysis by Zhang et al. (2016) examined 46 prospective studies involving more than 1.2 million individuals. Every 10-bpm increase in resting heart rate was associated with approximately a 9% higher risk of all-cause mortality and an 8% higher risk of cardiovascular mortality.
That is important epidemiological information.
But it does not mean the relationship should be interpreted as:
Lower = always healthier.
Going from a resting heart rate of 85 to 70 as cardiovascular fitness improves may be meaningful.
That does not mean getting from 55 to 42 would make someone even healthier.
There is no competition for the lowest resting heart rate.
Instead, resting heart rate should be interpreted alongside fitness, symptoms, medical history, medication use and, perhaps most importantly, your personal baseline.
Your Baseline May Matter More Than Someone Else's Number
This is one of the biggest advantages of modern wearable technology.
Instead of comparing your heart rate with the person sitting next to you, you can begin comparing you with you.
Imagine your resting heart rate usually sits between 58 and 62 bpm.
For several years, that has been normal for you. You exercise regularly, feel great, have normal exercise tolerance and have no concerning symptoms.
A reading of 58 probably means something very different for you than it would for someone whose resting heart rate has historically been 75 and suddenly begins recording values in the upper 40s.
The absolute number matters.
But so does the trend.
This is one of the reasons longitudinal data can be more valuable than a single reading.
Your wearable becomes much more useful when you stop asking:
"Is 54 good?"
and start asking:
"Is 54 normal for me, and what else is happening with my health and performance?"
A Low Resting Heart Rate Is Not Always From Fitness
There are several reasons someone's heart rate may be lower that have nothing to do with having exceptional cardiovascular fitness.
Certain medications, particularly medications that intentionally slow heart rate, can lower resting heart rate. Thyroid disorders, electrolyte abnormalities, changes within the heart's electrical conduction system and other medical conditions can also contribute to bradycardia.
Heart rate also typically falls during sleep and periods of deep relaxation.
This is why seeing a low number on your smartwatch without any additional context tells us surprisingly little.
A 48-bpm resting heart rate in an endurance-trained athlete who feels fantastic is very different from a newly developed 48-bpm heart rate in a relatively sedentary adult experiencing dizziness and unusual fatigue.
Same number.
Very different context.
When Should You Pay Attention?
A low resting heart rate becomes more important when it is new, unexplained, unusually low for you, or accompanied by symptoms.
Symptoms that deserve medical attention can include:
- dizziness or lightheadedness
- fainting or near-fainting
- unexplained weakness or significant fatigue
- unusual shortness of breath
- chest discomfort
- confusion
- dramatically reduced exercise tolerance
- difficulty getting your heart rate to rise appropriately during activity
Those symptoms do not automatically mean a serious heart problem exists, but they are reasons to discuss the situation with an appropriate medical professional rather than assuming that a low heart rate is simply evidence that you are fit.
And if you take medication that affects heart rate, your numbers should always be interpreted in that context.
Don't Confuse Resting Heart Rate With Heart Rate Recovery
There is another heart-rate measurement I frequently discuss with clients: heart rate recovery.
These are related concepts, but they are not the same thing.
Resting heart rate tells us how frequently your heart is beating while your body is at rest.
Heart rate recovery looks at how quickly your heart rate begins returning toward baseline after exercise ends.
When I coach cardiovascular training, I am often less interested in simply seeing how high someone's heart rate can climb and more interested in how appropriately the cardiovascular system responds to increasing demand and how efficiently it begins recovering afterward.
Your cardiovascular system should be able to do both.
Accelerate when demand increases.
And recover when demand decreases.
That is a much more complete picture of cardiovascular function than simply chasing the lowest resting number possible.
How Should You Measure Your Resting Heart Rate?
If you want your resting heart rate to become a useful performance metric, consistency matters.
Try measuring it under similar conditions. Early morning measurements can work well: after waking, before caffeine, before training and before the demands of your day significantly change your physiology.
Wearables make this easier because they collect large amounts of data automatically.
But avoid becoming overly reactive to a single morning.
Poor sleep, stress, alcohol, dehydration, illness, medication changes and numerous other factors can influence heart rate.
Look for patterns rather than isolated numbers.
This same principle applies to many of the metrics I use when evaluating health and human performance.
One data point gives you information.
A trend gives you context.
Multiple measurements viewed together give you a much better picture.
What Does Your Resting Heart Rate Actually Mean for You?
If you remember only one thing from this article, remember this:
Resting heart rate is a physiological clue, not a diagnosis and not a fitness score.
A lower resting heart rate may reflect excellent cardiovascular conditioning. Research clearly demonstrates relationships between regular exercise, greater cardiorespiratory fitness and lower resting heart rates (Gonzales et al., 2023; Reimers et al., 2018).
But a low number needs to be interpreted within the context of your health history, medications, symptoms, training background and normal baseline.
And although higher resting heart rates are associated with poorer long-term outcomes at the population level, that does not mean that continuously driving your heart rate lower provides continuously increasing benefits (Zhang et al., 2016).
Your goal should not be to win the resting-heart-rate contest.
Your goal should be to develop a cardiovascular system capable of supporting the life you want to live.
Can you handle sustained aerobic work?
Can your heart increase its output when demand rises?
Can you recover efficiently?
Is your cardiorespiratory fitness improving?
Can you climb stairs, hike, run, bike, play sports or simply keep up with life without your cardiovascular system becoming the limiting factor?
Those questions tell us considerably more about performance than one number on your Apple Watch.
The Bottom Line
If your resting heart rate is below 60 bpm, don't immediately panic...and don't immediately celebrate.
Ask a better question:
Why is it low?
If you have trained consistently, have strong cardiorespiratory fitness, feel good and the number is normal for you, a low resting heart rate may simply reflect an efficient cardiovascular system.
If the number is new, unexplained or accompanied by symptoms, it deserves a closer look.
That is how health and performance data should be used.
Not to collect numbers.
To understand what those numbers are telling us.
References
Climstein, M., Graham, K. S., Stapelberg, M., Walsh, J., DeBeliso, M., Adams, K., Sevene, T., & Harris, C. (2025). Electrocardiographic assessment of national-level triathletes: Sinus bradycardia and other electrocardiographic abnormalities. Sports, 13(1), 25. https://doi.org/10.3390/sports13010025
Gonzales, T. I., Jeon, J. Y., Lindsay, T., Westgate, K., Perez-Pozuelo, I., Hollidge, S., Wijndaele, K., Rennie, K., Forouhi, N., Griffin, S., Wareham, N., & Brage, S. (2023). Resting heart rate is a population-level biomarker of cardiorespiratory fitness: The Fenland Study. PLOS ONE, 18(5), e0285272. https://doi.org/10.1371/journal.pone.0285272
Reimers, A. K., Knapp, G., & Reimers, C.-D. (2018). Effects of exercise on the resting heart rate: A systematic review and meta-analysis of interventional studies. Journal of Clinical Medicine, 7(12), 503. https://doi.org/10.3390/jcm7120503
Zhang, D., Shen, X., & Qi, X. (2016). Resting heart rate and all-cause and cardiovascular mortality in the general population: A meta-analysis. CMAJ, 188(3), E53–E63. https://doi.org/10.1503/cmaj.150535