Is a resting heart rate of 40 BPM good?
By Aditya Ganapathi · Co-Founder of Cora · April 16, 2026
A resting heart rate of 40 BPM is considered low — elite athlete range for most adults. At 40 BPM, your reading is well below the standard AHA adult range of 60–100 BPM, typical of trained endurance athletes. This typically indicates exceptional cardiovascular efficiency from significant aerobic conditioning.
How 40 BPM compares to RHR norms by age
The American Heart Association defines a normal adult resting heart rate as 60–100 BPM, but population averages vary by age group. The table below shows AHA-referenced typical ranges for each adult age band and where 40 BPM falls relative to each group.
| Age Group | AHA Average (BPM) | Typical Range (BPM) | 40 BPM is… |
|---|---|---|---|
| 18–25 | ~68 | 62–73 | 28 BPM below average |
| 26–35 | ~69 | 62–75 | 29 BPM below average |
| 36–45 | ~70 | 63–76 | 30 BPM below average |
| 46–55 | ~70 | 63–77 | 30 BPM below average |
| 56–65 | ~70 | 61–77 | 30 BPM below average |
| 65+ | ~69 | 62–76 | 29 BPM below average |
Sources: American Heart Association; Nauman et al. (2011), JAMA; Reimers et al. (2018), European Journal of Preventive Cardiology. Age-group averages are approximate population means — individual variation is wide. See the full resting heart rate by age guide.
What a resting heart rate of 40 BPM typically indicates
A resting heart rate of 40 BPM places you squarely in the elite athlete category. The AHA defines a normal adult range as 60–100 BPM; values below 60 BPM reflect highly trained cardiovascular systems, and 40 BPM is near the very bottom of what healthy adults record. Professional endurance athletes — elite cyclists, marathon runners, and triathletes — regularly see morning readings in the 38–45 BPM range. This so-called "athletic bradycardia" results from cardiac remodeling: years of aerobic training enlarge the left ventricle, increase stroke volume, and lower the heart's intrinsic rate because each beat delivers far more blood than an untrained heart can.
Nauman et al. (2011), studying 29,325 adults in the HUNT Fitness Study published in JAMA, found that resting heart rate below 50 BPM was associated with the lowest all-cause and cardiovascular mortality in their cohort — the opposite of what many assume about very low RHR. For a healthy, active individual, 40 BPM is a marker of exceptional cardiovascular efficiency, not concern.
Context matters. If 40 BPM is your stable waking average and you feel energetic, perform well athletically, and have no symptoms of dizziness or fainting, this is an enviable baseline. If 40 BPM is a sudden drop from a higher norm, or accompanied by lightheadedness or syncope, it warrants medical evaluation to rule out pathological causes.
What affects your resting heart rate
Resting heart rate responds to both chronic and acute factors. Chronic influences — fitness level, body composition, long-term stress — set your baseline over months. Acute factors can shift your reading by 5–15 BPM day to day:
- 1
Fitness level: The strongest long-term driver. Regular aerobic exercise — particularly Zone 2 cardio — increases stroke volume and lowers intrinsic heart rate over months.
- 2
Sleep quality and duration: Even one night of poor sleep can elevate RHR by 3–8 BPM. Chronic sleep restriction chronically maintains elevated sympathetic tone.
- 3
Stress: Psychological stress activates the sympathetic nervous system, directly raising heart rate. Chronic work stress, anxiety, or life events can maintain elevated RHR for weeks.
- 4
Caffeine: Stimulates the sympathetic nervous system. High intake (3+ cups of coffee per day) can maintain RHR 3–7 BPM higher than your caffeine-free baseline.
- 5
Medications: Beta-blockers lower heart rate; stimulants (ADHD medications, decongestants), thyroid hormone, and certain asthma medications raise it. Review with your prescriber if relevant.
- 6
Hydration: Dehydration reduces blood volume, forcing the heart to beat faster to maintain output. Even mild dehydration (1–2%) can raise RHR 5–10 BPM.
What to do about a resting heart rate of 40 BPM
- 1
Continue training consistently — your cardiovascular system is adapting well. Protect this baseline with adequate sleep (8+ hours) and regular recovery weeks.
- 2
Monitor for drops below 38 BPM with symptoms — if you experience persistent dizziness or near-fainting, consult a sports cardiologist.
- 3
Track your 7-day rolling average. A sudden jump of 8+ BPM from this baseline can be an early sign of overtraining, illness, or dehydration.
- 4
Annual physical with ECG is reasonable to confirm your low RHR is physiological athlete's bradycardia and not a conduction disorder.
Track your resting heart rate trend with Cora
Cora reads your heart rate data from Apple Watch or Garmin and tracks your rolling 7-day and 30-day RHR baseline — flagging meaningful changes so you know when something is shifting.
Download Cora — FreeWhen to see a doctor
See a doctor if your 40 BPM reading is new and unexpected (not a longtime athlete), or if it's accompanied by fainting, near-syncope, persistent fatigue, or chest discomfort.
Frequently asked questions about a resting heart rate of 40 BPM
Is a resting heart rate of 40 BPM dangerous?
For a trained endurance athlete, 40 BPM is not dangerous — it reflects physiological adaptation. For a non-athlete who has not previously had such a low rate, 40 BPM can indicate a heart conduction abnormality and should be evaluated by a doctor.
What kind of athletes have a 40 BPM resting heart rate?
Elite cyclists, marathon runners, triathletes, and Nordic skiers commonly record resting heart rates in the 38–45 BPM range. Miguel Indurain, five-time Tour de France winner, famously had a resting heart rate near 28 BPM — an extreme outlier, but illustrative of how far cardiac adaptation can go.
Does a 40 BPM RHR mean I have bradycardia?
Technically yes — bradycardia is defined as a heart rate below 60 BPM. But there is a critical distinction between physiological (athletic) bradycardia and pathological bradycardia. Athletic bradycardia at 40 BPM is normal and healthy. Pathological bradycardia involves symptoms like dizziness or syncope and often indicates a conduction problem.
Should I exercise if my resting heart rate is 40 BPM?
If you are a trained athlete for whom 40 BPM is your normal baseline, yes — exercise as planned. If 40 BPM is unusually low for you and you feel unwell, hold intense exercise and consult a healthcare provider first.
Want full context on RHR by age? Resting Heart Rate by Age: Normal Ranges and What They Mean covers the complete population data, age-group comparisons, and how to interpret your trend. You can also check your specific rate against age norms with our resting heart rate calculator.