Understanding your heart rate zones transforms cardio training from guesswork into science. Whether you are a complete beginner or preparing for your first marathon, training in the right zone ensures you build fitness efficiently without overtraining or underdoing it.
💡 FitNFO includes a Heart Rate Zone Calculator and a Target Heart Rate Calculator — both free, both accurate.
The Five Heart Rate Training Zones
- Zone 1 (50–60% max HR) — Very light. Active recovery, warm-up, cool-down.
- Zone 2 (60–70% max HR) — Light. Fat burning, aerobic base building. The most underused zone.
- Zone 3 (70–80% max HR) — Moderate. Aerobic fitness, improves cardiovascular efficiency.
- Zone 4 (80–90% max HR) — Hard. Lactate threshold, race pace training.
- Zone 5 (90–100% max HR) — Maximum effort. Short intervals, speed work, VO2 max training.
How to Calculate Maximum Heart Rate
The traditional formula is 220 minus your age. A more accurate formula for women is 206 minus 88% of age. For trained athletes, the Tanaka formula (208 − 0.7 × age) is often more accurate. FitNFO calculates zones using the most appropriate formula for your age and gender.
Why Zone 2 Training Is Having a Moment
Zone 2 training — low-intensity steady-state cardio at 60–70% of maximum heart rate — has gained massive attention in longevity and performance research. Dr. Peter Attia and others have highlighted its role in improving mitochondrial function, metabolic health, and aerobic capacity. Most recreational athletes spend too much time in Zone 3 and not enough in Zone 2.
Practical Application
Use a heart rate monitor during training. Calculate your zones with FitNFO. Aim for 80% of training volume in Zone 2 and 20% in Zone 4–5 if you follow polarised training. This approach builds your aerobic base while avoiding chronic fatigue from too much moderate-intensity work.
Calculate Your Heart Rate Zones
Free with FitNFO — no account, no sign-up required.