What Heart Rate Should You Hit During Exercise?
What heart rate should you hit during exercise?
Target Heart Rate Calculator
Heart Rate Zones, VO₂ Max & Training Plan
Personalised Zones 1–5 using Karvonen or simple % MHR — results update in real time.
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Max HR Formula
Zone Method
Results are estimates only and do not constitute medical advice. Consult a qualified healthcare professional before making health decisions.
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Training at the right intensity makes the difference between wasted effort and genuine cardiovascular adaptation. Too easy, and your heart never gets the stimulus needed to strengthen. Too hard, too often, and you accumulate fatigue that prevents recovery and actually degrades fitness. Heart rate zones give you a science-based framework for hitting the right intensity for each training goal. Your maximum heart rate (MHR) is the ceiling of your cardiovascular output. Everything else in heart rate training is expressed as a percentage of that ceiling. The classic estimate — 220 minus your age — is widely used but has a standard deviation of ±10-12 bpm. The Tanaka formula (208 − 0.7 × age) is more accurate for adults over 40. This calculator offers both plus the Karvonen formula which uses your resting heart rate for a personalized target heart rate range. The 5 training zones correspond to distinct physiological adaptations: Zone 1 (recovery), Zone 2 (aerobic base building / fat oxidation), Zone 3 (aerobic capacity), Zone 4 (lactate threshold), and Zone 5 (VO2 max / speed development). Most endurance athletes benefit most from spending 80% of training time in Zones 1-2 and 20% in Zones 4-5 — a principle known as polarized training.
- →Setting up heart rate zones for a structured training plan
- →Knowing what BPM range to target for fat burning vs aerobic vs HIIT sessions
- →Calibrating cardio equipment (treadmill, bike, rowing machine) to correct intensity
- →Understanding whether your current exercise intensity is achieving your stated goal
- →Planning recovery runs and easy days at the right easy intensity
Laura, 42, is training for a half marathon. Resting heart rate: 58 bpm. Using the Tanaka formula: Max HR = 208 − (0.7 × 42) = 179 bpm. Her Zone 2 range (aerobic base) using Karvonen: 60-70% HRR = (179−58) × 0.60 + 58 to (179−58) × 0.70 + 58 = 131–143 bpm. Her long runs should stay within this range. Zone 4 (threshold) at 80-90%: 155–167 bpm — for tempo intervals only.
What is the Karvonen formula and why is it better?
The Karvonen formula uses Heart Rate Reserve (HRR = Max HR − Resting HR) to personalize training zones. Because it accounts for your fitness baseline (resting HR), it gives different target zones to a fit person with a low resting HR vs a sedentary person with the same max HR. It's more accurate for individuals than simple percentage-of-max calculations.
What heart rate zone burns the most fat?
Zone 2 (60-70% MHR) maximizes fat oxidation as a percentage of energy use. However, higher zones burn more total calories per hour. For weight loss, total caloric expenditure matters more than fat oxidation percentage. The practical advantage of Zone 2 is sustainability — you can do it for longer with less recovery demand.
How do I find my actual maximum heart rate?
The most accurate method is a supervised maximal exercise test. A practical field test: after a thorough warm-up, run 3 hard 400m repeats at all-out effort, with 2 minutes rest between. Your highest recorded HR in the final repeat is close to your MHR. Note: maximal effort tests are not recommended for beginners or those with cardiovascular conditions.
What is Zone 2 training and why is it so popular?
Zone 2 training (approximately 60-70% MHR or 65-75% HRR) is a low-intensity aerobic pace where you can hold a conversation but are working. Recent research, popularized by performance scientists like Dr. Inigo San Millan, shows that consistent Zone 2 work builds mitochondrial density and aerobic base — the foundation of all endurance performance.