Heart rate zones divide your heart rate into five intensity levels, each producing different training effects:
- Zone 1 (50–60% max HR): Very light — warm-up, recovery
- Zone 2 (60–70%): Light — fat burning, endurance base
- Zone 3 (70–80%): Moderate — aerobic fitness improvement
- Zone 4 (80–90%): Hard — performance, anaerobic threshold
- Zone 5 (90–100%): Maximum — sprints, VO2max training
Finding Your Max Heart Rate
Simple estimate: 220 - your age. A 30-year-old has an estimated max HR of 190 bpm. Zone 2 would be 114–133 bpm.
Karvonen Formula (More Accurate Than Age-Based)
The simple 220-minus-age formula ignores individual fitness level. The Karvonen method factors in resting heart rate: Target HR = ((Max HR − Resting HR) × %Intensity) + Resting HR. Two people the same age with very different fitness levels can have meaningfully different training zones under this formula.
Zone 2 Training's Popularity
Zone 2 (light, conversational-pace effort) has become popular in endurance and longevity research for building aerobic base and mitochondrial efficiency without the recovery cost of high-intensity work — many coaches recommend the majority of weekly training volume stay in this zone.