Heart Rate Zone Calculator

Target heart rate zones for fat burn, cardio and peak effort.

Overview

Calculates aerobic and anaerobic target heart rate training zones (Zone 1 through Zone 5) based on maximum heart rate and resting heart rate.

Formula & Calculation Method

Max HR (Tanaka) = 208 - (0.7 × Age) | Target HR (Karvonen) = [(Max HR - Resting HR) × % Intensity] + Resting HR

Zone 1: Active Recovery (50-60%), Zone 2: Aerobic Base (60-70%), Zone 3: Tempo (70-80%), Zone 4: Lactate Threshold (80-90%), Zone 5: Anaerobic Max (90-100%).

Worked Example: 35-Year-Old Runner with 60 bpm Resting Heart Rate

Inputs: Age = 35 | Resting Heart Rate = 60 bpm | Method = Karvonen Formula

  • Estimated Max Heart Rate = 208 - (0.7 × 35) = 183.5 bpm
  • Heart Rate Reserve (HRR) = 183.5 - 60 = 123.5 bpm
  • Zone 2 Aerobic Base (60% to 70% HRR) = [123.5 × 0.60] + 60 = 134 bpm to [123.5 × 0.70] + 60 = 146 bpm

Summary: Max HR = 184 bpm | Zone 1 (Recovery) = 122-134 bpm | Zone 2 (Aerobic Base) = 134-146 bpm | Zone 4 (Threshold) = 159-171 bpm

Common Use Cases

  • Zone 2 Endurance Base Building: Build mitochondrial density and fat oxidation capacity through conversational-pace running.
  • High-Intensity Interval Training (HIIT): Calibrate sprint intervals to ensure efforts reach true Zone 5 (> 90% HR max).
  • Cardiovascular Recovery Monitoring: Track morning resting heart rate trends to detect overtraining and systemic fatigue.

Frequently Asked Questions

What is Zone 2 training and why is it popular?

Zone 2 (60-70% max HR) trains your slow-twitch muscle fibers to burn fat as fuel efficiently, building a massive aerobic cardiovascular engine.

What is cardiac drift?

A natural physiological phenomenon where heart rate gradually drifts upward during prolonged exercise even though running pace stays constant, caused by dehydration and body heating.

How does resting heart rate reflect fitness?

A lower resting heart rate (typically 45-60 bpm in fit individuals) indicates a stronger stroke volume, meaning your heart pumps more blood per beat.

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