Heart Rate Zone Calculator (Karvonen)

Why Calculate Heart Rate Zones?

In sports science, Intensity Control is the key to progress. By using heart rate zones, you can precisely manage your training stimulus, ensuring your body operates within the correct metabolic pathways. Zone 2 builds a powerful aerobic base, while Zones 4-5 improve your VO2 Max.

Karvonen Formula: More Accurate than 220-Age

Most basic devices use the 220 - Age formula, which ignores individual fitness levels. The Karvonen Formula** incorporates your **Resting Heart Rate (RHR) to calculate your "Heart Rate Reserve (HRR)." This means as your fitness improves and your RHR drops, your zones adjust automatically, providing truly personalized training.

The Five Training Zones Explained

• Zone 1 (50-60% HRR)**: **Recovery & Warm-up. Ideal for the day after intense training; promotes circulation without added fatigue.
• Zone 2 (60-70% HRR)**: **Aerobic Base / Fat Burn. The most critical zone for athletes; increases mitochondrial density for better endurance.
• Zone 3 (70-80% HRR)**: **Aerobic Power. Breathing becomes noticeably deeper; perfect for Tempo runs.
• Zone 4 (80-90% HRR)**: **Lactate Threshold. The key zone for practicing lactate clearance and speed endurance.
• Zone 5 (90-100% HRR)**: **Anaerobic Peak. Short bursts of max effort to increase power and VO2 Max.

FAQ

Q: When is the best time to measure Resting Heart Rate (RHR)? A: We recommend measuring it for one minute immediately after waking up, while still in bed. This provides the most accurate baseline for your metabolic state.

Q: What if I feel exhausted, but my heart rate stays low? A: Heart rate is affected by stress, sleep, and hydration. If your Rate of Perceived Exertion (RPE) is high but your heart rate doesn't match, you may be overtrained and should lower your intensity.