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Target Heart Rate

General

Exercise Intensity Heart Rate Zone

The range of heartbeats per minute during exercise that indicates you are working at an appropriate intensity for cardiovascular fitness or fat burning, expressed as a percentage of maximum heart rate.

Definition

Target heart rate (THR) is the recommended range of heartbeats per minute during aerobic exercise that produces a specific training effect — whether fat burning, cardiovascular conditioning, or performance improvement. It is expressed as a percentage range of your Maximum Heart Rate (MHR).

Training at the right intensity — not too easy (no conditioning stimulus) and not so hard you cannot sustain it — is the fundamental principle of effective cardiovascular exercise. Target heart rate zones provide a simple, measurable proxy for exercise intensity without requiring sophisticated equipment.

Heart rate zones are used in running, cycling, swimming, rowing, and HIIT training to structure workouts around specific physiological adaptations.

Formula

Maximum Heart Rate (MHR):

MHR = 220 − Age (Haskell & Fox — simplest)

MHR = 208 − (0.7 × Age) (Tanaka — more accurate for older adults)

Target Heart Rate Range (basic method):

THR = MHR × (Low% to High%)

e.g., Moderate zone: MHR × 0.50 to MHR × 0.70

Karvonen Formula (Heart Rate Reserve method — more precise):

THR = RHR + (MHR − RHR) × Intensity%

Where RHR = Resting Heart Rate (measured upon waking, before rising from bed).

Worked Example

A 32-year-old with a resting heart rate of 58 bpm.

  • MHR (Haskell) = 220 − 32 = 188 bpm
  • Heart Rate Reserve (HRR) = 188 − 58 = 130 bpm

Training zones (Karvonen):

Zone % HRR Formula Target HR
Recovery 50% 58 + (130 × 0.50) 123 bpm
Fat Burn 60% 58 + (130 × 0.60) 136 bpm
Cardio 70% 58 + (130 × 0.70) 149 bpm
Hard 80% 58 + (130 × 0.80) 162 bpm
Max 90% 58 + (130 × 0.90) 175 bpm

Use the target heart rate calculator to generate your personalised zones and pair with the calories burned calculator to estimate energy expenditure by zone.

Key Things to Know

  • Individual variability: The 220 − Age formula can be off by ±15–20 bpm for any individual. If you regularly feel that Zone 2 feels far too easy or impossibly hard, consider a field test (fastest sustainable 20-minute run/cycle average HR ≈ lactate threshold HR ≈ ~85% MHR for most people).
  • Zone 2 for longevity: Research from Dr. Peter Attia and others has highlighted Zone 2 training (60–70% MHR, comfortable conversational pace) as the most important zone for metabolic health, mitochondrial density, and long-term cardiovascular fitness. Most people spend too little time here and too much in "the grey zone" (70–80%).
  • HIIT and Zone 4–5: High-intensity interval training (HIIT) involves short bursts at 85–95% MHR with recovery intervals. It improves VO2 max and cardiovascular efficiency efficiently but requires more recovery time. For general fitness, 80% Zone 2 + 20% Zone 4–5 is a widely recommended weekly split.
  • Relationship to BMR and TDEE: Higher-intensity training (Zone 4–5) burns more calories per minute but is sustainable for shorter durations. Zone 2 training typically burns 200–400 calories/hour depending on body weight. Use the TDEE calculator to factor workout calories into your total daily energy expenditure.
  • Beta-blockers and heart rate: Some medications (beta-blockers for blood pressure/heart conditions) artificially lower heart rate. Users of these medications should not use age-based MHR formulas for training guidance — consult a physician for appropriate intensity guidance.

Related Calculators

Target Heart Rate Calculator →Calculate your target heart rate zone for fat burning, cardio, and peak performance training. Uses the Karvonen formula with your age and resting heart rate for accurate results.
Calories Burned Calculator →Calculate calories burned during exercise based on your weight, activity type, and duration. Covers running, cycling, swimming, yoga, badminton, and 15+ activities. Free online calculator.
TDEE Calculator →Calculate your Total Daily Energy Expenditure (TDEE) based on your BMR and activity level. Find your maintenance calories for weight loss or muscle gain.

Related Terms

TDEETotal Daily Energy ExpenditureBMRBasal Metabolic RateBMIBody Mass IndexOne Rep MaxOne-Repetition Maximum (1RM)

Frequently Asked Questions

The most widely used formula is MHR = 220 − Age (Haskell & Fox, 1970). A 35-year-old has an estimated MHR of 185 bpm. The formula is a statistical average with high individual variability — standard deviation is roughly ±10–12 bpm, meaning two 35-year-olds could have MHRs of 175 or 195 and both be normal. More accurate alternatives include the Tanaka formula (MHR = 208 − 0.7 × Age) and direct measurement via a maximal exercise test.
Zone 1 (50–60% MHR): Very light, recovery, warm-up. Zone 2 (60–70% MHR): Fat burning, aerobic base building, conversational pace. Zone 3 (70–80% MHR): Aerobic conditioning, slightly laboured breathing. Zone 4 (80–90% MHR): Anaerobic threshold, hard but sustainable for intervals. Zone 5 (90–100% MHR): Maximum effort, VO2 max training, can only sustain briefly. Most fitness benefits come from consistent Zone 2 training, with periodic Zone 4–5 work for improvement.
The 'fat burning zone' burns a higher percentage of calories from fat, but a lower total number of calories compared to higher-intensity zones. For weight loss, total calorie expenditure matters more than fuel source. Higher-intensity training burns more total calories per minute and continues burning calories post-exercise (EPOC effect). A combination of mostly Zone 2 with some higher-intensity intervals is optimal for both fat loss and cardiovascular health.
The Karvonen formula incorporates your Resting Heart Rate (RHR) to produce Target HR ranges: Target HR = RHR + (MHR − RHR) × Intensity%. A fitter person has a lower RHR, so the Karvonen formula gives them a proportionally different target HR than the basic % of MHR approach. For example, a 35-year-old with MHR 185 and RHR 50 at 70% Karvonen intensity = 50 + (185−50) × 0.70 = 50 + 94.5 = 144.5 bpm, versus 185 × 0.70 = 129.5 bpm using the basic formula.
The most accurate methods are: (1) Chest strap heart rate monitor — picks up electrical signals from the heart, very accurate even at high intensities; (2) Wrist-based optical sensors (smartwatches, Fitbit, Garmin) — convenient, accurate at steady-state but less reliable during high-intensity interval training; (3) Manual carotid or wrist pulse count — take your pulse for 10 seconds and multiply by 6. For training zones, consistent measurement method matters more than absolute accuracy.