Heart Rate Zones
Heart rate zones divide exercise intensity into categories based on percentage of maximum heart rate. Learn how to calculate and use heart rate zones for effective training.
Quick Answer
Heart Rate Zones — are intensity categories based on percentage of your maximum heart rate (or heart rate reserve). They range from Zone 1 (very easy) to Zone 5 (maximum effort) and help guide training intensity for different fitness adaptations.
What are Heart Rate Zones?
Heart rate zones divide exercise intensity into categories, each targeting different physiological adaptations:
| Zone | % Max HR | % HRR | Description |
|---|---|---|---|
| Zone 1 | 50-60% | 50-60% | Very easy, recovery |
| Zone 2 | 60-70% | 60-70% | Easy, aerobic development |
| Zone 3 | 70-80% | 70-80% | Moderate, aerobic/anaerobic |
| Zone 4 | 80-90% | 80-90% | Hard, threshold |
| Zone 5 | 90-100% | 90-100% | Very hard, VO2 Max |
Use our Zone 2 Heart Rate Calculator.
Calculating Your Zones
Method 1: Maximum Heart Rate
Find Max HR:
- Age-predicted: 220 - age (rough estimate)
- 206.9 - (0.67 × age) (more accurate)
- Field test: Hard effort to exhaustion
Calculate zones:
Zone HR = Max HR × Zone %
Example (Max HR = 180):
- Zone 2: 180 × 0.60 to 180 × 0.70 = 108-126 bpm
Method 2: Heart Rate Reserve (Karvonen)
More accurate because it accounts for resting HR:
Formula:
Target HR = Resting HR + (Max HR - Resting HR) × Zone %
Example (Max 180, Resting 50):
- Zone 2: 50 + (180-50) × 0.60 to 0.70 = 128-141 bpm
Method 3: Threshold-Based
Define zones relative to lactate threshold heart rate:
| Zone | % of LTHR |
|---|---|
| Zone 1 | < 81% |
| Zone 2 | 81-89% |
| Zone 3 | 90-93% |
| Zone 4 | 94-99% |
| Zone 5a | 100-102% |
| Zone 5b | 103-106% |
5-Zone vs 7-Zone Systems
5-Zone System
| Zone | Name | Purpose |
|---|---|---|
| 1 | Recovery | Active recovery |
| 2 | Endurance | Aerobic base |
| 3 | Tempo | Muscular endurance |
| 4 | Threshold | FTP/LT development |
| 5 | VO2 Max | Aerobic capacity |
7-Zone System (Power-Matched)
| Zone | Name | Purpose |
|---|---|---|
| 1 | Active Recovery | Blood flow |
| 2 | Endurance | Aerobic base |
| 3 | Tempo | Muscular endurance |
| 4 | Threshold | FTP improvement |
| 5 | VO2 Max | Aerobic ceiling |
| 6 | Anaerobic | Short, intense |
| 7 | Neuromuscular | Sprints |
Training with Heart Rate
Benefits
| Advantage | How It Helps |
|---|---|
| Accessible | Most wearables measure HR |
| Accounts for conditions | Adjusts for heat, fatigue |
| Easy to understand | Simple zone system |
| Works without power meter | Available to all athletes |
Limitations
| Limitation | Issue |
|---|---|
| Lag time | 30-60 second delay |
| Variability | Caffeine, sleep, stress affect HR |
| Cardiac drift | HR rises over long efforts |
| Not precise for intervals | Too slow to respond |
HR vs Power Training
| Factor | Heart Rate | Power |
|---|---|---|
| Response time | 30-60 seconds | Instant |
| Affected by conditions | Yes | No |
| Cost | Low | Higher |
| Best for | Easy/endurance work | All intensities |
| Precision | Moderate | High |
For most athletes, combining both is ideal:
- HR for Zone 2/easy work
- Power for intervals and threshold
Zone Purposes and Adaptation
Zone 1 (Recovery)
| Purpose | Workout Type |
|---|---|
| Active recovery | Very easy spin/jog |
| Blood flow | Post-hard workout |
| Not much training benefit | Just recovery |
Zone 2 (Endurance)
| Purpose | Workout Type |
|---|---|
| Aerobic base | Long, easy efforts |
| Fat oxidation | 80% of training |
| Mitochondrial development | Foundation for all |
Read: Benefits of Zone 2 Training.
Zone 3 (Tempo)
| Purpose | Workout Type |
|---|---|
| Muscular endurance | Steady-state efforts |
| "No man's land" | Use strategically |
| Bridge zone | Connects easy and hard |
Zone 4 (Threshold)
| Purpose | Workout Type |
|---|---|
| Lactate threshold | Tempo runs, threshold intervals |
| FTP improvement | Key development zone |
| Race pace simulation | 10K-half marathon pace |
Zone 5 (VO2 Max)
| Purpose | Workout Type |
|---|---|
| Aerobic ceiling | Short, hard intervals |
| Maximum oxygen uptake | 3-5 min efforts |
| Racing preparation | 5K pace development |
Common Training Distribution
The 80/20 Approach
| Zone | % of Training Time |
|---|---|
| Zone 1-2 | 80% |
| Zone 4-5 | 20% |
| Zone 3 | Minimize |
This polarized approach produces optimal adaptations for most endurance athletes.
Factors Affecting Heart Rate
Cardiac Drift
HR increases over time at constant effort due to:
- Dehydration
- Heat accumulation
- Fatigue
Daily Variation
| Factor | Effect on HR |
|---|---|
| Poor sleep | +5-10 bpm |
| Caffeine | +5-10 bpm |
| Heat | +10-20 bpm |
| Altitude | +10-20 bpm |
| Overtraining | +5-15 bpm resting |
Common Questions
How do I find my max HR?
Best methods:
- Field test (3-min all-out effort after warm-up)
- Racing (often reach near-max)
- Age formula (less accurate): 220 - age
Why is my HR higher than expected?
Check for:
- Caffeine
- Dehydration
- Heat
- Poor sleep
- Accumulated fatigue
- Starting too fast
Should I train by HR or power?
Use both:
- HR for easy/Zone 2 work
- Power for intervals and threshold
- HR as backup/validation
How often should I retest?
- Max HR: Rarely changes (maybe yearly)
- Threshold HR: Every 4-8 weeks
- Resting HR: Monitor regularly