Karvonen Formula Zone 2 Calculator
*Zone 2 is typically 60% to 70% of your Heart Rate Reserve (HRR).
What is the Karvonen Formula?
The Karvonen Formula is a mathematical method used to determine your target heart rate training zones. Unlike simple percentage-of-max-HR methods, the Karvonen formula incorporates your Resting Heart Rate (RHR), making it a much more personalized and accurate tool for athletes and fitness enthusiasts.
By calculating your Heart Rate Reserve (HRR)—the difference between your maximum heart rate and your resting heart rate—this formula accounts for your current cardiovascular fitness level. As your fitness improves and your resting heart rate drops, your training zones will shift accordingly.
Why Zone 2 Training?
Zone 2 training is often referred to as "Base Training." It is the intensity at which you are primarily using aerobic metabolism (fat oxidation) for fuel. Key benefits include:
- Mitochondrial Efficiency: Increases the number and efficiency of mitochondria in your muscle cells.
- Metabolic Flexibility: Improves your body's ability to burn fat as fuel.
- Faster Recovery: Enhances blood flow and waste removal without overstressing the central nervous system.
- Lactate Clearance: Teaches your body to clear lactate more effectively at higher intensities.
How the Calculation Works
The math behind this calculator follows these steps:
- Determine Max HR: If not provided, we use the Fox formula (220 – Age).
- Calculate HRR: Heart Rate Reserve = Max HR – Resting HR.
- Target HR: (HRR × Intensity%) + Resting HR.
Practical Example
If you are 40 years old with a Resting HR of 60 BPM:
- Estimated Max HR: 220 – 40 = 180 BPM
- HRR: 180 – 60 = 120 BPM
- 60% Intensity: (120 × 0.60) + 60 = 132 BPM
- 70% Intensity: (120 × 0.70) + 60 = 144 BPM
In this scenario, your target Zone 2 training range is 132 to 144 beats per minute.