Estimated max HR (Tanaka)
208 − 0.7 × age. More accurate across all ages than the older 220 − age formula.
Calculate your training heart rate zones using the Karvonen method — based on age and resting HR. Plus how to use each zone in your week.
Calculate your training heart rate zones using the Karvonen method — the gold standard for endurance training. Karvonen accounts for resting heart rate, which means a fit 35-year-old gets different zones than an unfit 35-year-old, even at the same age.
Heart rate zones are a way to prescribe effort that survives bad days, hot weather, and changing fitness. Pace tells you what you did; heart rate tells you what it cost. The Karvonen method calculates zones as percentages of your heart rate reserve (max HR − resting HR), then adds them back to your resting HR. That's more accurate than simple 'percentage of max' methods because it scales with your actual cardiovascular fitness.
208 − 0.7 × age. More accurate across all ages than the older 220 − age formula.
Zone HR = resting HR + (max HR − resting HR) × intensity %. Intensity bands: Z1 50–60%, Z2 60–70%, Z3 70–80%, Z4 80–90%, Z5 90–100%.
A 40-year-old runner with a resting heart rate of 50 bpm wants to find their 70% (moderate-intensity) training zone.
Calculation. First, calculate heart rate reserve: (220 − 40) − 50 = 130 bpm. Then, find the target heart rate: (130 × 0.70) + 50 = 141 bpm.
Takeaway. To train at a moderate intensity, this runner should aim for a heart rate of approximately 141 bpm.
A 28-year-old lifter with a resting heart rate of 65 bpm wants to calculate their 50% (very light-intensity) heart rate for a warm-up.
Calculation. First, calculate heart rate reserve: (220 − 28) − 65 = 127 bpm. Then, find the target heart rate: (127 × 0.50) + 65 = 129 bpm.
Takeaway. For recovery or warm-up periods, this lifter should target a heart rate around 129 bpm.
Fix. Measure your resting heart rate first thing in the morning before getting out of bed or consuming caffeine. For best results, take a measurement for three consecutive days and use the average.
Percentage-of-max ignores your resting HR, which means it gives the same zones to a sedentary person and a trained athlete of the same age. Karvonen is consistently more accurate.
Most endurance research points to 60–80% of total weekly conditioning time in Z2. For a hybrid lifter, that's typically 1–2 sessions of 30–60 min.
Most watches default to percentage-of-max with an estimated max HR. Inputting your real resting HR and using Karvonen will give better zones.
Recheck resting HR and re-run every 8–12 weeks. Aerobic adaptations move slowly — not week to week.