Heart Rate Zone Calculator: Training Zones by Age and Max HR

The Five Heart Rate Training Zones

Heart rate training zones divide exercise intensity into five bands, each with different physiological effects and training purposes. All zones are defined as percentages of Maximum Heart Rate (MHR).

Finding Your Maximum Heart Rate

The widely-used 220 − age formula is a population average with high individual variation (± 10–12 bpm). Better options:

Tanaka Formula (more accurate for older adults): MHR = 208 − (0.7 × age)

Gellish Formula: MHR = 206.9 − (0.67 × age)

Example — 42-year-old: - 220 − 42 = 178 bpm (simple formula) - Tanaka: 208 − (0.7 × 42) = 179 bpm - Gellish: 206.9 − (0.67 × 42) = 179 bpm

For high accuracy, determine actual MHR via a maximal exercise test or note the highest HR observed during a very hard hill sprint or interval.

Zone Calculations: Worked Example

42-year-old with MHR = 179 bpm:

What Each Zone Develops

Zone 1 (50–60%): Active recovery. Light walking, very easy cycling. Used the day after hard workouts to promote blood flow without stress.

Zone 2 (60–70%): Aerobic base building — the most important zone for endurance development. Training here increases mitochondrial density and fat oxidation capacity. Elite endurance athletes spend 70–80% of total training volume in Zone 2. At this intensity, you should be able to hold a full conversation.

Zone 3 (70–80%): Often called the "grey zone" by endurance coaches — too hard to promote maximum aerobic adaptation, not hard enough for high-intensity benefits. Useful for tempo runs and moderate-intensity steady state.

Zone 4 (80–90%): Lactate threshold training. This is where race-pace training happens for most runners. Sustainable for 20–60 minutes. Increases lactate threshold, allowing faster pace before fatigue accumulates.

Zone 5 (90–100%): VO2max intervals and sprints. Short bursts of 30 seconds to 4 minutes at maximum effort. Increases maximal oxygen uptake, running economy, and speed.

The 80/20 Principle

Research from elite endurance training shows that 80% of training volume at low intensity (Zone 1–2) and 20% at high intensity (Zone 4–5) produces better results than "moderate all the time" training for most athletes.

This polarized approach builds a large aerobic base (Zone 2) and peak capacity (Zone 4–5) without excessive training stress from middle-intensity work.

Resting Heart Rate as a Recovery Indicator

Track morning resting heart rate (before getting out of bed). An elevation of 5–8+ bpm above your baseline often signals: - Incomplete recovery - Overtraining - Onset of illness - Excessive stress

Elite athletes average resting HR of 40–55 bpm; well-trained amateur athletes 50–65 bpm.