Zone 2 Heart Rate Calculator
Optimize your aerobic base and fat metabolism
Your Zone 2 Target Range
This range is calculated using the Karvonen Formula (60% – 70% of Heart Rate Reserve).
What is Zone 2 Heart Rate Training?
Zone 2 training is a specific intensity of exercise that focuses on building your aerobic base. It is typically defined as 60% to 70% of your maximum heart rate or, more accurately, 60-70% of your heart rate reserve (HRR). At this intensity, your body primarily uses fat as fuel through mitochondrial oxidation, making it the "fat-burning zone."
Why Zone 2 is Critical for Longevity and Performance
Athletes and health enthusiasts prioritize Zone 2 for several science-backed reasons:
- Mitochondrial Efficiency: It stimulates the growth and efficiency of mitochondria, the powerhouses of your cells.
- Metabolic Health: Improved insulin sensitivity and better lactate clearance.
- Endurance Foundation: Builds the "engine" required for longer sessions without fatiguing the central nervous system.
- Faster Recovery: Because it is low impact, you can perform it frequently without overtraining.
How This Calculator Works
We use the Karvonen Formula, which is considered superior to the basic "220 minus age" method because it accounts for your individual fitness level via your Resting Heart Rate (RHR). Here is the math behind the logic:
- Max Heart Rate (MHR): 220 – Age
- Heart Rate Reserve (HRR): MHR – Resting HR
- Zone 2 Low (60%): (HRR × 0.60) + Resting HR
- Zone 2 High (70%): (HRR × 0.70) + Resting HR
Zone 2 Example Calculation
If you are 40 years old with a resting heart rate of 60 BPM:
- MHR: 220 – 40 = 180 BPM
- HRR: 180 – 60 = 120 BPM
- Zone 2 Lower Bound: (120 × 0.60) + 60 = 132 BPM
- Zone 2 Upper Bound: (120 × 0.70) + 60 = 144 BPM
In this example, your target for a Zone 2 workout would be to keep your heart rate between 132 and 144 beats per minute.