Fitness and age shape your resting heart rate

Your resting heart rate is how many times your heart beats per minute when you are still and calm. Most adults average somewhere in the mid 60s to low 70s, but one person's normal can sit anywhere from about 40 to over 100, so your own baseline matters more than the average. Regular endurance training tends to bring it down. It stays fairly steady from week to week, though about 1 in 5 people see at least one week where it swings by 10 beats or more.

Why it works

Aerobic training makes the heart pump more blood with each beat and strengthens vagal tone, the calming nerve signal that slows the heart at rest. So the heart needs fewer beats to move the same amount of blood. Losing fitness, getting sick, or feeling stressed weakens that calming signal, and resting heart rate climbs.

The evidence

• Quer, G., Gouda, P., Galarnyk, M. et al. (2020). Inter- and intraindividual variability in daily resting heart rate and its associations with age, sex, sleep, BMI, and time of year: Retrospective, longitudinal cohort study of 92,457 adults. PLOS ONE.

  Across 92,457 adults wearing fitness trackers (nearly 33 million daily readings over a median of 320 days), the average resting heart rate was 65.5 bpm, but individual averages ranged from about 40 to 109 bpm, a spread of roughly 70 bpm between people. Differences between people were far larger than changes within a person: for about 80% of individuals the largest swing in their own resting heart rate within any single week was under 10 bpm. Resting heart rate was lowest at a BMI near 21 to 23 and with 7 to 7.5 hours of sleep, was about 2 bpm higher in January than July, and rose with age until about 50 before declining. Age, sex, BMI, and sleep together explained only 10% of the differences between people, meaning each person has a fairly stable personal baseline.

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• Ostchega, Y., Porter, K.S., Hughes, J. et al. (2011). Resting Pulse Rate Reference Data for Children, Adolescents, and Adults: United States, 1999-2008. National Health Statistics Reports.

  Using U.S. NHANES exams from 1999 to 2008, this report built national reference values for resting pulse rate from a normative sample of 35,302 people who had no condition or medication affecting pulse (out of 49,114 examined). Resting pulse falls steeply with age in early life: a mean of 129 bpm under age 1, dropping to 96 bpm by age 5, to 78 bpm in early adolescence, then leveling off around 72 bpm in adulthood. Pulse was measured after the person sat quietly for about 4 minutes. The report provides percentile tables by age, sex, and race/ethnicity so a given reading can be compared against population norms.

• 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.

  Across all comparisons, resting heart rate fell more in exercise groups than controls (-3.3 bpm, -4.7%; SMD -0.29). Endurance training and yoga lowered resting heart rate significantly in both sexes. Larger drops came with a higher starting resting heart rate.

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Why we call confidence high

Three large sources anchor this. U.S. NHANES reference data on 35,302 people put the average adult resting pulse around 72 bpm (Ostchega 2011). Wearable data from 92,457 people found a mean of 65 bpm, individual averages from 40 to 109 bpm, and differences by age, sex, BMI, sleep and time of year (Quer 2020). A meta-analysis of 191 exercise trials found regular exercise lowers resting heart rate, with endurance training doing so in both men and women (Reimers 2018).

Where it applies

Adults. Reference values come from U.S. population samples (NHANES exams and wrist-tracker users); the training effect comes from controlled exercise trials in healthy people.