Why is Zone 2 training so popular for endurance and fat loss?

Zone 2 (60%–70% of Heart Rate Reserve) maximizes mitochondrial efficiency and fat oxidation while producing minimal fatigue, allowing athletes to train longer and build cardiovascular endurance.

How do I accurately measure my resting heart rate?

Measure your pulse for 60 seconds first thing in the morning right after waking up while still lying quietly in bed, or use an optical fitness tracker.

How does the Tanaka formula compare to 220 minus age?

The traditional 220 − age formula tends to underestimate max heart rate in older adults and overestimate it in younger adults. The Tanaka equation (208 − 0.7 × age) was derived from a meta-analysis of over 18,000 subjects.

Heart Rate Zones Calculator

Calculate your maximum heart rate and target training zones for fat burning, aerobic cardio, and VO2 max.

Cardiovascular Inputs

Your age (years)

Resting heart rate (BPM)

Measured in the morning before getting out of bed. Average adult: 60–80 BPM.

Maximum Heart Rate (Tanaka)

186 BPM

Tanaka: 208 − (0.7 × 32) = 186 BPM · Fox: 220 − 32 = 188 BPM

Resting HR

65 BPM

Heart Rate Reserve

121 BPM

Target Heart Rate Training Zones (Karvonen Method)

Target HR zones calculated using Heart Rate Reserve (HRR) personalized to your resting heart rate.

Zone 1: Very Light

50%–60%

126 – 138 BPM

Warm-up, active recovery, everyday metabolic health

Zone 2: Light / Fat Burn

60%–70%

138 – 150 BPM

Endurance base, fat oxidation, conversational pace

Zone 3: Moderate / Aerobic

70%–80%

150 – 162 BPM

Cardiovascular fitness, marathon pace, aerobic capacity

Zone 4: Hard / Threshold

80%–90%

162 – 174 BPM

Lactate threshold, high performance, heavy breathing

Zone 5: Maximum / VO2 Max

90%–100%

174 – 186 BPM

Peak sprints, short anaerobic intervals, all-out effort

Estimate only — not medical adviceView details

Consult your physician before starting intense heart rate training or high-intensity interval training (HIIT), especially if taking heart or blood pressure medications.

How it works

The Heart Rate Zones Calculator calculates your maximum heart rate and five personalized aerobic training zones using the Karvonen method.

Maximum Heart Rate is calculated using the modern Tanaka formula (208 − 0.7 × age), which research has shown to be more accurate across diverse age groups than the traditional Fox formula (220 − age).

The Karvonen method accounts for your Resting Heart Rate (Heart Rate Reserve), ensuring training targets reflect your baseline cardiovascular fitness.

Zones range from Zone 1 (active recovery) through Zone 2 (fat burn / aerobic base) up to Zone 5 (anaerobic threshold and VO2 max).

Frequently asked questions

Why is Zone 2 training so popular for endurance and fat loss?: Zone 2 (60%–70% of Heart Rate Reserve) maximizes mitochondrial efficiency and fat oxidation while producing minimal fatigue, allowing athletes to train longer and build cardiovascular endurance.
How do I accurately measure my resting heart rate?: Measure your pulse for 60 seconds first thing in the morning right after waking up while still lying quietly in bed, or use an optical fitness tracker.
How does the Tanaka formula compare to 220 minus age?: The traditional 220 − age formula tends to underestimate max heart rate in older adults and overestimate it in younger adults. The Tanaka equation (208 − 0.7 × age) was derived from a meta-analysis of over 18,000 subjects.