Target Heart Rate Zone Calculator
Calculate your exercise heart rate zones using the Karvonen method (heart rate reserve) for optimal training intensity. Zones range from recovery (50-60% HRR) to anaerobic (90-100% HRR).
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Karvonen more accurate than % Zone 2 for fat burn Zone 4-5 for intervals
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Why: Training in the right heart rate zone maximizes exercise benefits while minimizing injury risk.
How: Enter your age, resting heart rate, and fitness goal. The Karvonen formula calculates personalized heart rate zones.
Run the calculator when you are ready.
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For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
🏥 Health Facts
Zone 2 (60-70%) optimal for fat burn
— ACSM
Karvonen accounts for resting HR
— AHA
Target heart rate zones help you train at the right intensity. The Karvonen formula (heart rate reserve method) is more accurate than simple percentage of max HR because it accounts for your resting heart rate. Max HR ≈ 220 − Age (or Tanaka: 208 − 0.7×Age). Five zones map to different training goals: fat burn (Zone 2), cardio (Zone 3), threshold (Zone 4), peak (Zone 5).
Sources: ACSM, AHA, Karvonen 1957, CDC.
Key Takeaways
- • Karvonen formula: THR = [(MHR − RHR) × %Intensity] + RHR
- • Zone 2 (60-70%) optimal for fat burn and aerobic base
- • Zone 4-5 for speed, power, VO2max (limit to intervals)
- • AHA: 50-70% moderate, 70-85% vigorous
Did You Know?
How Does the Karvonen Formula Work?
Heart Rate Reserve
HRR = Max HR − Resting HR. This is your "usable" range. A fit person with low RHR has a larger reserve.
Target HR Calculation
THR = Resting HR + (HRR × %Intensity). Example: RHR 60, MHR 180, 70% → 60 + (120 × 0.70) = 144 bpm.
Why It's Better
Simple % of max HR ignores fitness. Karvonen personalizes zones using your RHR, giving more accurate training targets.
Expert Tips
5 Heart Rate Zones
| Zone | % Max HR | Purpose |
|---|---|---|
| Zone 1 — Recovery | 50–60% | Recovery, warm-up |
| Zone 2 — Fat Burn | 60–70% | Fat burn, endurance |
| Zone 3 — Aerobic | 70–80% | Cardio fitness |
| Zone 4 — Anaerobic | 80–90% | Lactate threshold |
| Zone 5 — Maximum | 90–100% | VO2max, peak |
Frequently Asked Questions
What is the Karvonen formula?
THR = [(Max HR − Resting HR) × %Intensity] + Resting HR. It accounts for fitness level via resting HR and is more personalized than the simple percentage method. Karvonen (1957) developed this heart rate reserve approach.
What are the 5 heart rate zone descriptions?
Zone 1 (50-60%): Recovery, warm-up. Zone 2 (60-70%): Fat burn, endurance. Zone 3 (70-80%): Aerobic fitness. Zone 4 (80-90%): Anaerobic threshold. Zone 5 (90-100%): Maximum effort, VO2max.
What is the max heart rate formula?
220 − Age is the classic estimate (Fox 1971). The Tanaka formula (208 − 0.7 × Age) is more accurate, especially for adults over 40. True max HR requires graded exercise testing.
Is the fat burn zone myth real?
Zone 2 burns a higher proportion of fat, but Zone 3-4 burns more total calories. For weight loss, total calorie expenditure matters most. A mix of Zone 2 and Zone 4 is optimal (ACSM).
How do I use heart rate zones in training?
Build aerobic base in Zone 2 (60-70%). Improve cardio in Zone 3. Push lactate threshold in Zone 4 (intervals). Peak efforts in Zone 5 (short bursts). Most training should be Zone 2-3.
How accurate is age-predicted max HR?
Standard deviation is ±10-12 bpm. Individual variation is high. Tanaka (208 − 0.7 × age) is more accurate than 220-age. For precision, use a graded exercise test or field test.
Key Statistics
Official Data Sources
⚠️ Disclaimer: Heart rate zones are estimates. Individual max HR varies ±10-12 bpm. Consult a physician before starting a new exercise program, especially with heart disease, high blood pressure, or diabetes. Stop if you experience chest pain, dizziness, or irregular heartbeat. Not medical advice.
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