Free Zone 2 Heart Rate Calculator: Karvonen Formula (Biohacker Edition)

Zone 2 training is the holy grail of metabolic health and longevity. It's the intensity where your body builds mitochondria and burns fat with maximum efficiency. But finding your exact Zone 2 requires precision. Our calculator uses the Karvonen Formula, which accounts for your resting heart rate for superior accuracy.

Why Biohackers Obsess Over "Zone 2"

Zone 2 is defined as the highest metabolic output you can sustain while keeping lactate levels below 2 mmol/L. In this zone, you are training your Type 1 (slow-twitch) muscle fibers to utilize oxygen and fat more efficiently.

💡 Longevity Benefit: Dr. Peter Attia and other experts cite Zone 2 cardio as the single most potent tool for improving mitochondrial function and insulin sensitivity.

❤️ HEART RATE ANALYZER

Karvonen Method (Gold Standard)

Measure in bed upon waking.

Understanding Your 5 Zones

Zone 1: Recovery (50-60%)

Very light effort. Used for warm-ups, cool-downs, and active recovery. Improves blood flow without fatigue.

Zone 2: The "Biohacker Zone" (60-70%)

You should be able to hold a conversation, but it should feel slightly strained. This is where mitochondrial biogenesis happens. Aim for 150-180 minutes per week here.

Zone 5: VO2 Max (90-100%)

Maximum effort. Sustainable for only a few minutes. Crucial for increasing your aerobic ceiling and "engine size".

Frequently Asked Questions

Why is Karvonen better than 220-Age? +
The standard "220 minus age" formula ignores your fitness level. The Karvonen formula uses your Resting Heart Rate (RHR) to tailor the zones to your actual cardiovascular health.
How do I measure my Resting Heart Rate? +
The best time is immediately after waking up, before getting out of bed. Count your pulse for 60 seconds or use a wearable tracker.

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⚠️ Medical Disclaimer: This tool provides estimates. Always consult a cardiologist before starting high-intensity training, especially if you have pre-existing conditions.