#karvonen

Heart-rate training maths as an API. The max-heart-rate endpoint estimates maximum heart rate from age by the three common formulas — Fox (220 − age), Tanaka (208 − 0.7 × age) and Gulati (206 − 0.88 × age, validated for women). The zones endpoint returns the five training zones (recovery, endurance, aerobic, threshold and maximal) as beats-per-minute ranges, computed either as a simple percentage of the maximum heart rate or, when you give a resting heart rate, by the more accurate Karvonen heart-rate-reserve method. The target endpoint computes the target heart rate for any intensity, by percentage of max or by Karvonen. You can pass an age (and choose a formula) or give your own measured max heart rate. Everything is computed locally and deterministically, so it is instant and private. Ideal for fitness and running apps, wearables and gym equipment, coaching tools, and cardio training programmes. Informational only — not medical advice. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 4 endpoints. This is heart-rate maths; for BMI, BMR and calories use a health-calculator API and for running pace use a pace API.

api.oanor.com/heartrate-api