❤️ Heart Rate Zones Calculator

Classic (Fox, 1971): Max HR = 220 − Age Simple, widely used, but ±10-12 bpm error Tanaka (2001) — More Accurate: Males: Max HR = 208 − (0.7 × Age) Females: Max HR = 206 − (0.88 × Age) Validated on large samples, ±7 bpm error Gellish (2007): Max HR = 207 − (0.7 × Age) Better for older adults (60+) Best method: Actual lab max HR test (VO2 max test) or verified field test (e.g. 3-mile run all-out)

Zone 1 — Recovery: 50–60% of Max HR Very light, active recovery, warm-up/cool-down Zone 2 — Aerobic Base: 60–70% of Max HR Fat burning zone, builds aerobic base, conversational Zone 3 — Aerobic: 70–80% of Max HR Improves cardiovascular efficiency, moderate effort Zone 4 — Threshold: 80–90% of Max HR Lactate threshold, hard effort, improves pace Zone 5 — Max: 90–100% of Max HR VO2 max intervals, very hard, short durations only

Target HR = ((Max HR − Resting HR) × intensity%) + Resting HR HRR (Heart Rate Reserve) = Max HR − Resting HR Zone 2 lower bound: ((190 − 60) × 0.60) + 60 = (130 × 0.60) + 60 = 138 bpm Why Karvonen is better: It accounts for YOUR resting heart rate (fitness level) A fitter person with lower resting HR gets different zones than a sedentary person of the same age. Lower resting HR → lower zone boundaries (fitter people need less absolute HR for same effort)

Zone 2 (60-70% Max HR) — "Fat Burning Zone": Higher % of calories from fat (60-65% fat) But LOWER total calories burned Zone 4 (80-90% Max HR) — "Cardio Zone": Lower % from fat (40-45%) But MUCH HIGHER total calories burned Example: 30-minute workout, 70 kg person: Zone 2: 200 cal total → 130 cal from fat Zone 4: 350 cal total → 157 cal from fat Zone 4 burns MORE fat in absolute terms despite lower fat percentage. Both zones improve health.