Target Heart Rate (Karvonen)
Training heart rate at intensity I.
Formula
Variables
How it works
Karvonen’s formula estimates a training heart rate by scaling the heart-rate reserve, which is the gap between your maximum and resting heart rates. It works because exercise intensity is usually better represented as a fraction of that reserve than as a fraction of maximum heart rate alone, especially for people whose resting heart rates differ a lot. In effect, it sets the exercise target above resting level by the same proportion of reserve you want to use.
When to use it
Use this when planning aerobic training zones for running, cycling, rowing, or other steady-state cardio, especially in sports science, coaching, or personal training. It is also useful when comparing workout intensity across people with different resting heart rates.
Worked example, step by step
Given: HR_max = 190 bpm HR_rest = 58 bpm I = 0.70 Step 1: Find heart-rate reserve HR_max - HR_rest = 190 - 58 = 132 bpm Step 2: Apply the intensity 132 × 0.70 = 92.4 bpm Step 3: Add resting heart rate back in HR_target = 92.4 + 58 = 150.4 bpm Final answer: HR_target ≈ 150 bpm
Common mistakes to avoid
- Using the maximum heart rate alone and forgetting to subtract resting heart rate first
- Entering intensity as 70 instead of 0.70
- Using the formula for high-intensity interval spikes without accounting for the lag in heart-rate response
Did You Know?
Training in your target heart-rate zone maximises cardio benefit without overtaxing the heart.
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