High Intensity Heart Rate Calculator
Determine your optimal training zones for HIIT and aerobic performance.
Understanding High-Intensity Training Zones
High-Intensity Interval Training (HIIT) relies on reaching specific physiological thresholds to trigger cardiovascular and metabolic adaptations. Unlike steady-state cardio, high-intensity training requires pushing your heart rate into the 80% to 95% range of your Maximum Heart Rate (MHR).
The Karvonen Formula Explained
This calculator uses the Karvonen Formula, which is considered more accurate than simple age-based formulas because it accounts for your Resting Heart Rate (RHR). By calculating your Heart Rate Reserve (the difference between Max HR and Resting HR), the formula provides a more personalized target that reflects your current fitness level.
The Math:
1. Max Heart Rate = 220 (or 226) – Age
2. Heart Rate Reserve (HRR) = Max HR – Resting HR
3. Target HR = (HRR × Intensity%) + Resting HR
HIIT Intensity Levels
| Intensity | Zone Name | Typical Usage |
|---|---|---|
| 70% – 80% | Aerobic / Tempo | Sustained endurance, fat oxidation. |
| 80% – 90% | Anaerobic Threshold | HIIT Work intervals, improving lactic threshold. |
| 90% – 100% | VO2 Max / Redline | Short sprints, maximum power output. |
Example Calculation
If you are a 40-year-old male with a resting heart rate of 60 BPM and you want to perform HIIT at 85% intensity:
- Max HR: 220 – 40 = 180 BPM
- HRR: 180 – 60 = 120 BPM
- Target HR: (120 × 0.85) + 60 = 162 BPM
In this scenario, you should aim to maintain roughly 162 beats per minute during your high-intensity work intervals to maximize the benefits of the session.