Target Heart Rate Calculator
Calculate your target heart rate zones for different workout intensities using the Karvonen formula.
Heart Rate Training Zones
Target Heart Rate (THR) is the ideal heart rate range for specific workout goals. The Karvonen formula, considered more accurate than simpler methods, calculates THR using age, resting heart rate, and intensity percentage. Heart rate zones: Zone 1 (50-60% intensity): warm-up, recovery. Zone 2 (60-70%): fat burning, base building. Zone 3 (70-80%): aerobic capacity, endurance. Zone 4 (80-90%): lactate threshold, anaerobic. Zone 5 (90-100%): maximum effort, sprint. Resting Heart Rate (RHR) is measured first thing in the morning before getting out of bed—normally 60-100 bpm, athletes often 40-60 bpm. Training in Zone 2 (fat burning) improves endurance with minimal fatigue. To measure HR during exercise, count beats for 15 seconds and multiply by 4, or use a fitness watch. Consistent cardio training gradually lowers RHR and improves cardiovascular fitness. Always warm up before intense zones and cool down afterward.