Heart rate zones
Use age and resting heart rate to estimate five personalized training zones with the Karvonen heart-rate-reserve method.
For a better resting value
Measure for a full minute shortly after waking, before caffeine, and average several calm mornings.
The age-predicted maximum (220 − age) can differ substantially from your true maximum. Medications and heart conditions can change safe training zones.
Karvonen zones
125 bpm heart-rate reserve
Zone 1 · Recovery
Easy movement and warm-ups
Zone 2 · Aerobic / fat oxidation
Comfortable endurance work
Zone 3 · Cardio
Steady, moderately hard work
Zone 4 · Threshold
Hard intervals
Zone 5 · Peak
Very hard, short efforts
Educational estimates only—not medical advice, diagnosis or a substitute for a qualified clinician. Stop exercise and seek care for concerning symptoms.