Calculate your maximum heart rate and training heart rate zones for optimal exercise intensity.
Heart rate training zones divide your exercise intensity into ranges based on a percentage of your maximum heart rate (MHR). Training in different zones produces different physiological adaptations — from fat-burning and aerobic base building at lower intensities, to improved speed and anaerobic capacity at higher intensities.
This calculator uses the widely-used formula of 220 minus your age to estimate maximum heart rate. It's important to understand this is a population average with significant individual variation — actual maximum heart rate can differ from this estimate by 10-15 beats per minute or more in either direction. For more precise training, especially for competitive athletes, a supervised maximal exercise test provides a more accurate figure.
Zone 1 (50-60% of MHR) — Very Light: Used for warm-ups, cool-downs, and active recovery. Builds basic endurance with minimal stress on the body.
Zone 2 (60-70% of MHR) — Light/Aerobic Base: The foundation of endurance training. At this intensity, the body primarily uses fat for fuel, and you should be able to hold a conversation. Most endurance coaches recommend the majority of training volume occur in this zone.
Zone 3 (70-80% of MHR) — Moderate: Improves cardiovascular efficiency. Breathing becomes noticeably harder, and conversation becomes difficult.
Zone 4 (80-90% of MHR) — Hard/Threshold: Improves the body's ability to clear lactate and sustain harder efforts. Used in interval training.
Zone 5 (90-100% of MHR) — Maximum: Used for short, high-intensity intervals. Develops top-end speed and power but can only be sustained for brief periods.
Training by heart rate rather than pace or perceived effort alone provides an objective measure of internal physiological stress. Two people running the same pace might be in completely different heart rate zones depending on fitness level, fatigue, heat, or hydration status. This is why experienced coaches often emphasize heart rate (or power, for cycling) over pace for structured training.
What's a normal resting heart rate? For most adults, a normal resting heart rate falls between 60-100 beats per minute. Well-trained athletes often have resting heart rates in the 40s-50s due to increased cardiac efficiency. A consistently elevated resting heart rate can sometimes indicate inadequate recovery, illness, or stress.
Should I be concerned if my heart rate doesn't match my zones during exercise? Many factors affect heart rate response including medications (especially beta-blockers, which can significantly lower heart rate response), caffeine, hydration, sleep, and heat. If you notice persistent discrepancies or symptoms like dizziness or chest discomfort, consult a healthcare provider.
How accurate are heart rate monitors on fitness trackers? Wrist-based optical sensors are generally accurate for steady-state activities but can lag during rapid intensity changes. Chest strap monitors using electrical signals (similar to ECG) are typically more accurate, especially for high-intensity interval training.