Nutrition1 min read·Updated March 9, 2026
Heart Rate Training Zones: Zone 2 and Beyond
Understand the 5 heart rate training zones, how to calculate them, and which zone to prioritize for health and performance.
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Why Heart Rate Zones Matter
Different intensity levels stress different energy systems and produce different adaptations. Training in the wrong zone for your goal wastes time and may increase injury risk.
Estimating Max Heart Rate
Classic: 220 − age. More accurate (Tanaka): 208 − (0.7 × age).
Example, age 35: 208 − (0.7 × 35) = 183 bpm max
The 5 Zones
- Zone 1 (50–60%): Recovery — very easy, casual walk
- Zone 2 (60–70%): Aerobic base — conversational pace, builds mitochondria and fat-burning efficiency
- Zone 3 (70–80%): Aerobic — moderately hard, the "gray zone" most people overuse
- Zone 4 (80–90%): Threshold — improves lactate threshold, tempo runs
- Zone 5 (90–100%): VO2 Max — maximum effort, short intervals
The 80/20 Rule
Elite endurance athletes do ~80% of training in Zone 2 and 20% in Zones 4–5. Zone 3 is the "junk zone" — too hard for easy recovery, too easy for real adaptations. Build your aerobic base in Zone 2 for the greatest long-term health benefit.
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Frequently Asked Questions
What is Zone 2 cardio?
Zone 2 (60–70% max HR) is low-intensity steady-state cardio that maximizes mitochondrial adaptations and fat oxidation with minimal fatigue. The talk-test: you should hold a full conversation without gasping.
Is HIIT better than Zone 2?
They develop different adaptations. Optimal programs include both — majority volume in Zone 2 for aerobic base, some Zone 4–5 for VO2 max and performance.