Heart rate zone training uses your heart rate as a guide to exercise intensity. By training in specific zones, you can optimize workouts for fat burning, endurance building, or peak performance. The five zones are based on percentages of your maximum heart rate (MHR).
Finding Your Max Heart Rate
MHR = 220 − Age (basic estimate) MHR = 208 − (0.7 × Age) (Tanaka formula, more accurate) A 35-year-old has an estimated MHR of 185 bpm (basic) or 184 bpm (Tanaka). These are estimates; actual MHR varies by individual.
The Five Heart Rate Zones
| Zone | % of MHR | Feel | Benefit |
|---|---|---|---|
| Zone 1: Recovery | 50–60% | Very easy, conversational | Active recovery, warm-up |
| Zone 2: Aerobic Base | 60–70% | Comfortable, can talk in sentences | Fat burning, endurance base |
| Zone 3: Tempo | 70–80% | Moderate, can speak in phrases | Aerobic fitness, stamina |
| Zone 4: Threshold | 80–90% | Hard, only a few words | Speed endurance, VO2 max |
| Zone 5: Maximum | 90–100% | All-out, cannot speak | Peak power, sprint capacity |
Zone 2: The Fat-Burning Sweet Spot
Zone 2 has become the most discussed zone in fitness because it trains your aerobic engine without excessive fatigue. At 60–70% MHR, your body primarily uses fat for fuel. Most endurance athletes spend 80% of their training time in Zone 2. For general health and longevity, Zone 2 training (brisk walking, easy jogging, cycling) for 150–180 minutes per week provides enormous benefits.
How to Structure Training by Zone
- Beginners: 100% Zone 1–2 for the first 4–8 weeks to build aerobic base.
- Intermediate: 80% Zone 2, 20% Zone 3–4 (the 80/20 rule).
- Advanced: 80% Zone 2, 10% Zone 3, 10% Zone 4–5.
Track your calorie burn across zones with the TDEE Calculator and the Steps to Calories Calculator.
Key Takeaways
- Max heart rate estimate: 220 minus your age (or use the Tanaka formula).
- Zone 2 (60–70% MHR) is the primary fat-burning and endurance zone.
- The 80/20 rule: 80% easy training, 20% hard training for optimal results.
- Use a heart rate monitor for accuracy; perceived effort is unreliable for beginners.
Frequently Asked Questions
What heart rate zone burns the most fat?
Zone 2 (60-70% of max HR) burns the highest percentage of calories from fat. However, higher zones burn more total calories. For weight loss, total calorie burn matters more than the fat/carb ratio during exercise.
Is the 220-minus-age formula accurate?
It is a rough estimate with a margin of error of plus or minus 10-12 bpm. The Tanaka formula (208 - 0.7 x age) is slightly more accurate. The gold standard is a VO2 max lab test.
How long should I train in each zone?
Most evidence supports the 80/20 rule: 80% of training time in Zone 1-2 (easy), 20% in Zone 3-5 (moderate to hard). This applies to beginners through elite athletes.