Training in the right heart rate zone makes exercise significantly more effective. Whether your goal is fat burning, cardiovascular fitness, or peak performance, knowing your target heart rate range ensures you're working at the right intensity.
Maximum Heart Rate: The Foundation
Before calculating training zones, you need to estimate your maximum heart rate (MHR) — the highest number of beats per minute your heart can achieve under maximum exertion.
Simple formula (most commonly used):
MHR = 220 − age
Example: A 35-year-old:
MHR = 220 − 35 = 185 bpm
More accurate formulas:
Tanaka formula (better for older adults):
MHR = 208 − (0.7 × age)
Gellish formula (research-validated):
MHR = 207 − (0.7 × age)
For our 35-year-old: Tanaka → 208 − 24.5 = 183.5 bpm
Note: These are estimates. Your actual MHR can only be found through a maximal exercise test, and may differ significantly from the formula result.
The Karvonen Formula: Heart Rate Reserve
The Karvonen formula (Heart Rate Reserve method) is more precise because it accounts for your resting heart rate — a measure of cardiovascular fitness.
Target HR = ((MHR − Resting HR) × Intensity %) + Resting HR
How to measure your resting heart rate: Check your pulse immediately upon waking, before getting out of bed. Count beats for 60 seconds. Average over 3 days.
Typical resting heart rates:
- Untrained adult: 60–80 bpm
- Regular exerciser: 50–65 bpm
- Endurance athlete: 35–50 bpm
Example: 35-year-old, MHR = 185 bpm, resting HR = 62 bpm. Training at 70% intensity:
Target HR = ((185 − 62) × 0.70) + 62
= (123 × 0.70) + 62
= 86.1 + 62
= 148 bpm
Heart Rate Training Zones
Zone 1 – Recovery (50–60% MHR)
Very light activity. Walking, gentle cycling. Promotes recovery, develops base aerobic fitness.
Using 220-age for a 35-year-old (MHR = 185): Zone 1: 93–111 bpm
Zone 2 – Fat Burning / Base Endurance (60–70% MHR)
The "fat burning zone" — your body uses fat as the primary fuel source. Conversational pace; you can speak in full sentences.
Zone 2: 111–130 bpm
This is where most long-run training takes place. It's less dramatic than it sounds — you can sustain this for hours.
Zone 3 – Aerobic Fitness (70–80% MHR)
Moderate-to-hard effort. Breathing is laboured; you can speak in short phrases. Improves cardiovascular efficiency.
Zone 3: 130–148 bpm
Zone 4 – Anaerobic Threshold (80–90% MHR)
Hard effort at or near the lactate threshold — the point where lactic acid builds faster than it clears. This is race pace for most people.
Zone 4: 148–167 bpm
Zone 5 – Maximum Effort (90–100% MHR)
All-out effort sustainable for only short periods. VO2 max training. Very uncomfortable.
Zone 5: 167–185 bpm
Training Zones by Age
| Age | MHR est. | Zone 2 (60–70%) | Zone 3 (70–80%) | Zone 4 (80–90%) |
|---|---|---|---|---|
| 20 | 200 | 120–140 | 140–160 | 160–180 |
| 25 | 195 | 117–137 | 137–156 | 156–176 |
| 30 | 190 | 114–133 | 133–152 | 152–171 |
| 35 | 185 | 111–130 | 130–148 | 148–167 |
| 40 | 180 | 108–126 | 126–144 | 144–162 |
| 45 | 175 | 105–123 | 123–140 | 140–158 |
| 50 | 170 | 102–119 | 119–136 | 136–153 |
| 55 | 165 | 99–116 | 116–132 | 132–149 |
| 60 | 160 | 96–112 | 112–128 | 128–144 |
| 65 | 155 | 93–109 | 109–124 | 124–140 |
Which Zone Should You Train In?
For fat loss: Zone 2 burns the highest proportion of fat calories. However, higher-intensity zones burn more total calories, which also contributes to fat loss. A mix of both is optimal.
For cardiovascular health: Zone 2 training is the foundation of long-term heart health. Most training volume should be here (80% of sessions).
For performance: Include zone 3 and 4 work alongside zone 2 base training.
For beginners: Start with zone 2. Build a base over months before adding higher-intensity work.
How to Monitor Your Heart Rate
Chest strap: Most accurate. Detects electrical signals from the heart. Recommended for training.
Wrist-based optical (smartwatch): Convenient but less accurate, especially during high-intensity intervals. Good for zone 2 and daily monitoring.
Manual (carotid or radial pulse): Count for 15 seconds and multiply by 4. Not practical during exercise.
Rate of Perceived Exertion (RPE)
If you don't have a heart rate monitor, the Borg RPE scale correlates with heart rate zones:
| RPE (6–20 scale) | Intensity | Zone |
|---|---|---|
| 7–9 | Very light | 1 |
| 10–11 | Light | 2 |
| 12–13 | Somewhat hard | 3 |
| 14–16 | Hard | 4 |
| 17–19 | Very hard | 5 |
| 20 | Maximum | Max |