How to Calculate Heart Rate Zones for Training — 5-Zone System Explained
Why Heart Rate Zones Matter for Training
Training at the wrong intensity is the most common reason fitness progress stalls. Too easy and you under-stimulate adaptation. Too hard too often and you accumulate fatigue faster than you recover. Heart rate zones give you a physiologically grounded intensity framework based on your individual cardiovascular response.
Calculating Maximum Heart Rate
The most common formula is 220 − age. A 35-year-old has an estimated MHR of 185 bpm. The Tanaka formula (208 − 0.7 × age) is more accurate for older adults. For the most accurate MHR, a maximal exercise test (graded treadmill or cycling test) is needed. Heart Rate Zones uses both formulas so you can compare.
The 5 Zones and Their Effects
Zone 1 (50–60% MHR): Active recovery, very light aerobic. Zone 2 (60–70%): Fat burning, builds aerobic base — the ‘all day’ zone. Zone 3 (70–80%): Aerobic development, moderate intensity. Zone 4 (80–90%): Anaerobic threshold, lactate production — race pace. Zone 5 (90–100%): Maximal effort, sprint intervals — short bursts only.
How to Use Zones in Your Training Plan
For general fitness: 80% of training in Zone 2, 20% in Zone 4–5 (polarized training model). For endurance: build Zone 2 base for 4–6 months, then layer in Zone 4 work. For fat loss: Zone 2 burns the highest proportion of fat as fuel (though Zone 4 burns more calories per minute). For performance: Zone 4 intervals improve lactate threshold.
Frequently Asked Questions
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