Heart Rate Formulas
Max HR = 208 − (0.7 × age) (Tanaka, more accurate)
Karvonen formula: Target HR = RHR + (HRR × intensity%)
HRR (Heart Rate Reserve) = Max HR − Resting HR
Training Zones (Karvonen Method)
| Zone | % of HRR | Purpose |
|---|---|---|
| Zone 1 — Recovery | 50–60% | Warm-up, cool-down, active recovery |
| Zone 2 — Fat Burn | 60–70% | Fat oxidation, aerobic base building |
| Zone 3 — Cardio | 70–80% | Aerobic fitness, endurance improvement |
| Zone 4 — Threshold | 80–90% | Lactate threshold, speed endurance |
| Zone 5 — Max | 90–100% | VO2 max, peak performance, HIIT |
How to Measure Resting Heart Rate
Measure your resting heart rate first thing in the morning before getting out of bed. Count your pulse for 60 seconds (or 30 seconds and multiply by 2). Average adult RHR is 60–80 bpm. Athletes commonly have RHR of 40–60 bpm. A lower RHR generally indicates better cardiovascular fitness.
Frequently Asked Questions
Is Zone 2 training really the best for fat loss?
Zone 2 maximizes the percentage of calories from fat (up to 60–65% fat-derived at this intensity). However, higher intensity zones burn more total calories per minute. For overall fat loss, total calorie deficit matters most. Zone 2 is ideal for long, sustainable sessions and building aerobic base without excessive recovery demand.
Why is the 220-minus-age formula inaccurate?
The 220-age formula has a standard deviation of ±12 bpm — meaning for a 40-year-old, actual max HR could be anywhere from 168 to 192 bpm. The Tanaka formula (208 − 0.7×age) is slightly more accurate, especially for older adults. A true max HR test (during all-out exertion) gives the most precise value.
Can I exercise above Zone 5?
Zone 5 represents 90–100% of HRR, which is essentially maximum effort. Sustaining this for more than 30–90 seconds is not physiologically possible. High-intensity interval training (HIIT) uses short bursts into Zone 5 followed by Zone 1–2 recovery periods. Extended Zone 5 exercise is possible only for very short durations.