For a 43-year-old, the Tanaka formula estimates a maximum heart rate of about 178 bpm. That puts your Zone 2 (easy aerobic) at roughly 107–125 bpm and your Zone 4 (threshold) at 142–160 bpm. Below you will find the full 5-zone table, a formula comparison, and a calculator that personalises the numbers if you enter your resting HR.
| Zone | Name | % HRmax | BPM (age 43) |
|---|---|---|---|
| 1 | Recovery | 50–60% | 89–107 |
| 2 | Endurance | 60–70% | 107–125 |
| 3 | Aerobic | 70–80% | 125–142 |
| 4 | Threshold | 80–90% | 142–160 |
| 5 | Maximum | 90–100% | 160–178 |
No single equation is authoritative. The spread below shows why picking a formula matters — the difference between Fox and Nes at your age moves your Zone 2 ceiling by several beats.
| Formula | HRmax at age 43 |
|---|---|
| Fox (220 − age) | 177 |
| Tanaka (208 − 0.7 × age) | 178 |
| Gellish (207 − 0.7 × age) | 177 |
| Nes / HUNT (211 − 0.64 × age) | 183 |
| Gulati (206 − 0.88 × age, women) | 168 |
Using the Tanaka formula (208 − 0.7 × age), the estimated maximum heart rate for a 43-year-old is about 178 bpm. Population variability is roughly ±10–12 bpm, so your true HRmax could sit anywhere between 168 and 188 bpm.
Zone 2 for a 43-year-old is approximately 107–125 bpm, which corresponds to 60–70% of an estimated HRmax of 178 bpm. You should be able to hold a full conversation at this intensity.
Zone 4 (lactate threshold) for a 43-year-old is roughly 142–160 bpm — 80–90% of HRmax. At this intensity you can only speak in short phrases.
Enter your resting heart rate into the calculator to apply the Karvonen method, which anchors zones to your heart rate reserve. This is significantly more accurate than %HRmax alone, especially if you are trained or untrained.
Disclaimer: This calculator is for informational purposes only and does not provide medical advice. Always consult with a healthcare professional before starting any new exercise program.
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