Training at the right heart rate intensity is key to achieving specific fitness goals, whether that's fat burning, building aerobic endurance, or improving athletic performance. This heart rate zone calculator uses your age to estimate your maximum heart rate and then divides it into standard training zones, from light activity recovery zones to maximum effort anaerobic zones. Each zone corresponds to different physiological benefits, from fat metabolism in lower zones to VO2 max improvements in higher zones. Athletes, gym-goers, and anyone using a fitness tracker can use these zones to structure workouts more effectively and avoid overtraining.