Get personalized heart rate training zones based on your age and resting heart rate for smarter workouts.
Frequently Asked Questions
Heart rate zones are ranges of heartbeats per minute that correspond to different exercise intensities. There are 5 standard zones, from Zone 1 (very light recovery) to Zone 5 (maximum effort). Training in specific zones targets different physiological adaptations like fat burning, aerobic endurance, or speed.
The Karvonen formula uses your heart rate reserve (HRR) — the difference between your max and resting heart rates — to calculate more personalized training zones. The formula is: Target HR = ((Max HR - Resting HR) x % intensity) + Resting HR. It accounts for your fitness level since fitter people have lower resting heart rates.
Zone 2 (60-70% intensity) is traditionally called the 'fat burning zone' because the highest percentage of calories comes from fat at this intensity. However, higher-intensity zones burn more total calories and more total fat per minute. For fat loss, total calorie expenditure matters more than the percentage from fat.
Measure your resting heart rate first thing in the morning before getting out of bed. Place two fingers on your wrist or neck, count beats for 30 seconds, and multiply by 2. Do this for 3-5 consecutive mornings and take the average. Most fitness trackers also measure resting heart rate automatically.
Zone 2 training is excellent for building an aerobic base, and many endurance coaches recommend spending 80% of training time in Zones 1-2. However, a well-rounded program includes all zones. Zone 4-5 work builds speed, power, and lactate threshold. The 80/20 rule (80% easy, 20% hard) is a popular evidence-based approach.
Elite endurance athletes spend roughly 80% of their training in Zones 1-2 and only 20% at high intensity. This approach builds a massive aerobic base while allowing adequate recovery.