Heart Rate Zone Calculator (Fat Burn vs. Cardio)
Determine optimal heart rate zones for fat oxidation and endurance. Supports Karvonen, Tanaka, and Fox formulas for precise training targets.
| Zone | Intensity | Range (BPM) |
|---|
About
Effective training requires manipulating intensity to target specific physiological adaptations. Low-intensity exercise predominantly utilizes fat as fuel, while higher intensities shift the body's reliance toward glycogen (carbohydrates). Training in the "Fat Burn" zone maximizes lipid oxidation, making it efficient for weight management, whereas the "Cardio" zone improves aerobic capacity and heart health.
Generic charts often use outdated math. This tool provides granular control by implementing multiple algorithms. The Karvonen method, which accounts for Resting Heart Rate (RHR), offers the highest accuracy for individuals with varying fitness levels, ensuring the calculated zones reflect true metabolic effort.
Formulas
1. Maximum Heart Rate (MHR):
Standard (Fox):
Tanaka (More accurate for >40y):
2. Target Heart Rate (Karvonen):
This method uses Heart Rate Reserve (HRR).
Reference Data
| Zone | Intensity (% MHR) | Physiological Effect | Feel |
|---|---|---|---|
| Zone 1 | 50% − 60% | Warm Up / Recovery | Very easy conversation. |
| Zone 2 (Fat Burn) | 60% − 70% | Maximal Fat Oxidation | Breathing heavier, but comfortable. |
| Zone 3 (Aerobic) | 70% − 80% | Cardiovascular Endurance | Moderate sweating, short sentences. |
| Zone 4 (Threshold) | 80% − 90% | Lactate Tolerance | Uncomfortable, labored breathing. |
| Zone 5 (VO2 Max) | 90% − 100% | Peak Performance | Maximum effort, sustainable for seconds. |