Triathlon Heart Rate Training Zones Calculator
Enter your age and resting heart rate to calculate your five personalized heart rate training zones for triathlon swim, bike, and run workouts.
Why triathletes train by heart rate zones
Structuring swim, bike, and run sessions around heart rate zones helps balance easy aerobic-building work with harder efforts, which is the foundation of most endurance training plans. Training almost entirely in the wrong zone (too hard, too often) is one of the most common reasons athletes plateau or burn out.
The Karvonen (heart rate reserve) method
This calculator uses the Karvonen formula, which is generally considered more personalized than simple percent-of-max-HR methods because it also accounts for your resting heart rate (a rough marker of aerobic fitness). Heart rate reserve (HRR) is calculated as your max heart rate minus your resting heart rate. Each zone is then: Target HR = Resting HR + (HRR × zone percentage). If you don’t have a lab-tested max heart rate, the calculator estimates it with the widely used 220 minus age formula, though this can be off by 10-15 bpm for some individuals.
Zones 1-2 are typically used for the bulk of aerobic base and recovery training, Zone 3 for steady tempo work, and Zones 4-5 for threshold and high-intensity intervals. These figures are for general fitness planning purposes only and are not a substitute for guidance from a coach or a supervised fitness or cardiac assessment, especially if you have any heart-related health concerns.