The Gulati formula estimates a maximum heart rate of about 173 bpm for a 38-year-old woman. Population variability is roughly ±10–12 bpm, so your true HRmax could sit anywhere between 163 and 183. This page compares the five main formulas at your age and shows how the difference propagates into your training zones.
Gulati estimate for a 38-year-old woman: 173 bpm. Likely range 163–183 bpm.
| Formula | HRmax at age 38 |
|---|---|
| Fox (220 − age) | 182 |
| Tanaka (208 − 0.7 × age) | 181 |
| Gellish (207 − 0.7 × age) | 180 |
| Nes / HUNT (211 − 0.64 × age) | 187 |
| Gulati (206 − 0.88 × age, women) | 173 |
For women, Gulati (2010) is generally the most representative formula because it was derived from 5,437 female participants.
| Zone | Name | % HRmax | BPM (age 38, female) |
|---|---|---|---|
| 1 | Recovery | 50–60% | 87–104 |
| 2 | Endurance | 60–70% | 104–121 |
| 3 | Aerobic | 70–80% | 121–138 |
| 4 | Threshold | 80–90% | 138–156 |
| 5 | Maximum | 90–100% | 156–173 |
The Gulati formula estimates a maximum heart rate of about 173 bpm for a 38-year-old woman. Your true HRmax is likely between 163 and 183 bpm.
Gulati (2010) is generally recommended for women. It was derived from 5,437 female participants and corrects the systematic overestimation seen with male-derived formulas like Fox and Tanaka.
Each formula was derived from a different study population. Genetics account for roughly 50% of individual variation in HRmax, so no single equation fits everyone. A supervised maximal effort test is the only way to know your true HRmax.
Yes, if you are healthy and cleared for vigorous exercise. Warm up thoroughly, then perform a 3–5 minute all-out effort finishing with a 30–60 second sprint. Record the peak value on a chest strap monitor. Do not attempt this if you have a heart condition or are on rate-limiting medication.
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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