Find Your Heart Rate Zones for Training
Heart rate zones tell you how hard your body is working during exercise - from easy recovery to all-out sprint. Training in the right zones improves endurance, burns fat more efficiently, and prevents overtraining. This calculator gives you personalized zone targets based on age and resting heart rate.
Heart Rate Zones Explained
| Zone | Intensity | % of Max HR | What It Does |
|---|---|---|---|
| Zone 1 | Very light | 50-60% | Warm-up, recovery |
| Zone 2 | Light | 60-70% | Fat burn, aerobic base |
| Zone 3 | Moderate | 70-80% | Aerobic endurance |
| Zone 4 | Hard | 80-90% | Anaerobic, lactate threshold |
| Zone 5 | Maximum | 90-100% | Sprint, peak performance |
The Karvonen Formula
For accurate zone calculation, we use the Karvonen formula which includes your resting heart rate:
Max HR is estimated as 220 - age (or use 208 - 0.7 × age for a more modern formula).
Worked Example: 35-Year-Old, RHR 65
- Max HR: 220 - 35 = 185 bpm
- Heart rate reserve: 185 - 65 = 120
- Zone 2 (65%): (120 × 0.65) + 65 = 143 bpm
- Zone 3 (75%): (120 × 0.75) + 65 = 155 bpm
- Zone 4 (85%): (120 × 0.85) + 65 = 167 bpm
How to Measure Resting Heart Rate
- Measure immediately after waking, before getting out of bed
- Place two fingers on your wrist (radial pulse) or neck (carotid)
- Count beats for 30 seconds, multiply by 2
- Average over 3-7 mornings for accuracy
Training by Zone - Weekly Plan
- Zone 1-2: 60-80% of training time - the base of endurance
- Zone 3: 10-20% - tempo runs, moderate cycling
- Zone 4: 5-10% - interval training, threshold work
- Zone 5: 1-5% - sprints, race pace
Frequently Asked Questions
What is a normal resting heart rate?
Adults: 60-100 bpm. Athletes: 40-60 bpm. Below 60 in non-athletes may indicate bradycardia - see a doctor.
Is 220 - age accurate?
It is a rough estimate. Individual max HR varies by +/- 10-15 bpm. For accuracy, do a supervised max HR test.
What zone burns the most fat?
Zone 2 burns the highest PERCENTAGE of fat. But Zone 3-4 burns more TOTAL calories - overall fat loss depends on calorie deficit, not zone.
How long should I train in Zone 2?
For endurance: 80% of training time. For general fitness: 30-60 minutes, 3-4 times per week.
Can I use a smartwatch for HR?
Wrist-based optical sensors are 85-95% accurate at rest, less accurate during high-intensity intervals. Chest straps are more reliable.
Is high heart rate dangerous?
During exercise, a high rate is normal. At rest, sustained rates above 100 (tachycardia) warrant medical evaluation.