Triathlon Target Heart Rate Calculator
Enter your age, resting heart rate and target discipline. The Karvonen formula computes personalized heart-rate zones for triathlon training — accounting for the different intensity demands of swimming, cycling and running.
years
bpm
bpm
Target discipline
154 – 166 bpm (Karvonen HRR method)
- 1
Max HR
220 − 35 = 185Population estimate from the 220 − age formula. - 2
HR reserve (HRR)
185 − 60 = 125 - 3
Target HR (low end)
60 + 75% × 125 = 154Karvonen formula: HRrest + intensity fraction × HR reserve.
How does this calculator work?
THR = HRrest + f × (HRmax − HRrest) using the Karvonen formula (HRmax ≈ 220 − age). Triathlon target fractions: swim 65–75%, bike 70–80%, run 75–85% of heart rate reserve. Enter age and resting HR; override HRmax with your measured value for better accuracy.
Formula
How this is calculated
The Karvonen (heart-rate-reserve) formula personalises target heart rate by using the difference between maximum and resting heart rate — the reserve — rather than just maximum HR alone. For a given intensity fraction f: THR = HRrest + f × (HRmax − HRrest). A fitter person with a lower resting heart rate therefore trains at a higher absolute bpm for the same relative intensity.
Max HR is estimated as 220 − age (a widely used population average from Tanaka et al. revised formulas). Because individual HRmax can vary ±10–15 bpm from this estimate, the calculator accepts an optional measured override — ideally from a supervised maximal effort test or a lab VO₂max protocol.
Triathlon disciplines have different physiological demands on heart rate. Swimming produces lower heart rates than land-based exercise at the same oxygen consumption because the horizontal body position reduces the cardiac workload; target swim HR is typically 65–75% of HRR. Cycling is intermediate at 70–80% HRR. Running, being weight-bearing and upright, typically produces the highest HR at 75–85% HRR for race-pace efforts.
Frequently asked questions
When horizontal in water, the heart pumps against less gravitational resistance, reducing the effort needed to circulate blood. Cooler water also reduces body temperature, lowering the cardiovascular demand. As a result, your swim HR will be 5–15 bpm lower than cycling or running at a similar perceived effort or oxygen uptake.
Lie still for at least 5 minutes after waking — before getting up or having caffeine. Count your pulse for 60 seconds (or 30 seconds × 2) using fingertips on your wrist or neck. Repeat on several mornings and average the readings. Fitness trackers and heart-rate monitors can also give a reliable resting HR over several nights of sleep.
Using a straight percentage of HRmax (e.g., 70% HRmax) ignores fitness level. Two people with the same HRmax but different resting HRs (50 bpm vs. 80 bpm) have very different cardiovascular fitness. The Karvonen formula uses the HR reserve — the range between rest and max — so it scales the training zone to the individual, giving more accurate intensity targets.
Also known as
TG we-Calculate Editorial Team. (2026). Triathlon Target Heart Rate Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/triathlon-target-heart-rate-calculator
TG we-Calculate Editorial Team. "Triathlon Target Heart Rate Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/triathlon-target-heart-rate-calculator.
TG we-Calculate Editorial Team, "Triathlon Target Heart Rate Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/triathlon-target-heart-rate-calculator
@misc{wecalculate_triathlon_target_heart_rate_calculator, title = {Triathlon Target Heart Rate Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/triathlon-target-heart-rate-calculator}}, year = {2026}, note = {TG we-Calculate} }
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