Heart Rate Training Zones

Heart rate training zones are ranges of heart rates that correspond to different exercise intensities. There are typically 5 zones, from Zone 1 (light recovery) to Zone 5 (maximum effort). Training in specific zones targets different physiological adaptations: fat burning, aerobic endurance, lactate threshold, VO2max, and anaerobic power.

The Karvonen method calculates training zones using Heart Rate Reserve (HRR) — the difference between your maximum and resting heart rate. Zone HR = Resting HR + (HRR × target percentage). This method is more personalized than simple percentage-of-max-HR methods because it accounts for your fitness level through resting heart rate.

While lower intensities do burn a higher percentage of calories from fat, higher intensities burn more total calories and more total fat. For fat loss, total energy expenditure matters most. The 'fat burning zone' concept is technically accurate but misleading — it doesn't mean Zone 2 is optimal for losing body fat (Achten & Jeukendrup, 2004).

The classic '220 minus age' formula has a standard deviation of ±10-12 bpm. The Tanaka formula (208 − 0.7 × age) is more accurate, especially for older adults. However, individual variation is significant. For precise zones, a graded exercise test or field-based max HR test is recommended.