Zone 2 (Z2) Heart Rate Calculator
Percentage of Max HR (Standard)
Karvonen Formula (Uses Resting HR)
Your Target Zone 2 Range
What is Zone 2 Heart Rate Training?
Zone 2 training is often referred to as "Base Training." It is a steady-state intensity where your body primarily uses fat as a fuel source and builds aerobic capacity. This intensity is sustainable for long periods and is a cornerstone of professional endurance programs for runners, cyclists, and triathletes.
Why Train in Zone 2?
- Mitochondrial Density: Increases the number and efficiency of mitochondria in your muscle cells.
- Fat Metabolism: Teaches your body to burn fat more efficiently at higher workloads.
- Lactate Clearance: Improves your ability to clear lactic acid from the bloodstream.
- Reduced Injury Risk: Lower intensity allows for high volume without the systemic fatigue of HIIT.
How to Use Your Results
Your calculated range (60% to 70% of effort) should feel like a "conversational pace." You should be able to speak in full sentences without gasping for air. If you use the Karvonen Method, the calculator takes your fitness level (Resting Heart Rate) into account, which is often more accurate for trained athletes.
Example Calculation
For a 40-year-old with a resting heart rate of 60 BPM:
- Max Heart Rate: 220 – 40 = 180 BPM.
- Standard Zone 2 (60-70%): 108 to 126 BPM.
- Karvonen Zone 2: 132 to 144 BPM (Accounting for heart rate reserve).