Heart rate training provides an objective measure of internal effort that adjusts for variables like heat, fatigue, and terrain. By understanding and training in specific heart rate zones, you can ensure each run delivers the intended training stimulus—whether that's building aerobic base, improving lactate threshold, or developing speed.
What Are Heart Rate Zones?
Heart rate zones are ranges of heart beats per minute that correspond to different intensities and physiological demands. Each zone triggers specific adaptations in your cardiovascular system, muscles, and metabolism.
Why Heart Rate Training Works
- • Measures internal effort, not external pace
- • Adjusts automatically for heat, fatigue, and stress
- • Prevents overtraining on easy days
- • Ensures adequate intensity on hard days
- • Objective feedback independent of terrain
- • Tracks fitness improvements over time
As your fitness improves, you'll run faster at the same heart rate—a direct, measurable sign of progress that pace alone can't reveal on variable terrain or in changing conditions.
The 5 Heart Rate Zones Explained
Zone 1: Recovery (50-60% Max HR)
Feel: Very easy, could talk continuously
Purpose: Active recovery, warm-up/cool-down, easy days after hard workouts
Physiological benefit: Promotes blood flow for recovery without adding training stress
Zone 2: Aerobic Base (60-70% Max HR)
Feel: Comfortable, can hold conversation
Purpose: Building aerobic foundation, fat oxidation, endurance
Physiological benefit: Increases mitochondrial density, capillary networks, and aerobic enzyme activity. Should comprise 80% of training.
Zone 3: Tempo/Aerobic (70-80% Max HR)
Feel: Moderate, can speak in sentences
Purpose: Improving efficiency, marathon pace training
Physiological benefit: Enhances lactate clearance and running economy. Often called the "gray zone" because it's not easy enough for recovery or hard enough for major adaptations.
Zone 4: Threshold (80-90% Max HR)
Feel: Hard, only short phrases possible
Purpose: Raising lactate threshold, half marathon to 10K pace
Physiological benefit: Increases lactate threshold, improves sustainable speed. Sustainable for 20-60 minutes in trained runners.
Zone 5: VO2max/Anaerobic (90-100% Max HR)
Feel: Very hard to maximal, no talking
Purpose: Maximum oxygen uptake, 5K pace and faster
Physiological benefit: Improves VO2max, running power, and neuromuscular recruitment. Sustainable for only 3-8 minutes.
How to Calculate Maximum Heart Rate
Your maximum heart rate (MHR) is the foundation for calculating zones. While formulas provide estimates, individual variation is significant—some people's actual max HR differs by 20+ beats from predictions.
| Formula | Calculation | Best For |
|---|---|---|
| Classic | 220 - age | Quick estimate, less accurate |
| Tanaka (2001) | 208 - (0.7 × age) | Most accurate formula |
| Gulati (Women) | 206 - (0.88 × age) | Women specifically |
| Field Test | Actual measured max | Most accurate, gold standard |
Example Calculations (Age 35)
- • Classic: 220 - 35 = 185 bpm
- • Tanaka: 208 - (0.7 × 35) = 208 - 24.5 = 184 bpm
- • Gulati (Women): 206 - (0.88 × 35) = 206 - 30.8 = 175 bpm
Maximum Heart Rate Field Test
A field test provides your actual maximum heart rate, far more accurate than any formula. Only perform when rested and healthy.
3x3 Hill Test Protocol
Safety Warning
Max HR testing is extremely demanding. Consult a doctor if you have heart conditions, are over 40 and sedentary, or have risk factors for cardiovascular disease.
Calculating Your Personal Zones
Once you know your max HR, calculate your zones. Here's an example using max HR of 190 bpm:
| Zone | % of Max HR | HR Range (Max 190) | Training Purpose |
|---|---|---|---|
| Zone 1 | 50-60% | 95-114 bpm | Recovery |
| Zone 2 | 60-70% | 114-133 bpm | Aerobic base |
| Zone 3 | 70-80% | 133-152 bpm | Tempo |
| Zone 4 | 80-90% | 152-171 bpm | Threshold |
| Zone 5 | 90-100% | 171-190 bpm | VO2max |
Heart Rate Reserve Method (Karvonen)
For more precision, use heart rate reserve which accounts for resting heart rate:
Target HR = ((Max HR - Resting HR) × intensity%) + Resting HR
Example: Zone 2 at 65% with Max 190, Resting 50: ((190-50) × 0.65) + 50 = 141 bpm
→ Try our Karvonen Calculator for instant personalized zones
Zone 2 Training: The Foundation of Fitness
Zone 2 training has gained tremendous attention in endurance sports. Dr. Peter Attia, Dr. Inigo San Millan, and elite coaches emphasize that most training should occur in this zone.
Zone 2 Benefits
- • Mitochondrial biogenesis: Creates more cellular power plants
- • Fat oxidation: Trains body to burn fat efficiently
- • Capillary development: Better oxygen delivery to muscles
- • Lactate clearance: Improves ability to process lactate
- • Metabolic health: Improves insulin sensitivity
- • Low injury risk: Reduces mechanical stress
- • Recovery compatible: Can train frequently without overtraining
How to Know You're in Zone 2
Signs You're in Zone 2
- • Can hold full conversation
- • Breathing through nose possible
- • Feels "too easy" (that's correct!)
- • Could maintain for hours
- • Not building significant fatigue
Signs You're Too Hard
- • Need to pause for breath mid-sentence
- • Heavy breathing through mouth
- • Feels "moderate" (already too hard)
- • Legs starting to burn
- • Couldn't sustain for 2+ hours
Key insight: Most runners do Zone 2 too fast. If you can't nasal breathe, you're likely in Zone 3. Slow down—the aerobic adaptations require staying truly easy.
Polarized Training: Zone Distribution
Research shows elite endurance athletes follow an 80/20 distribution: 80% easy (Zone 1-2), 20% hard (Zone 4-5). Zone 3 is minimized.
The 80/20 Rule
- • 80% Zone 1-2: Easy running, builds aerobic base
- • ~0% Zone 3: "Gray zone"—too hard for recovery, too easy for adaptation
- • 20% Zone 4-5: Quality workouts that drive improvement
| Weekly Volume | Easy (80%) | Hard (20%) |
|---|---|---|
| 20 miles/week | 16 miles Zone 1-2 | 4 miles Zone 4-5 |
| 40 miles/week | 32 miles Zone 1-2 | 8 miles Zone 4-5 |
| 60 miles/week | 48 miles Zone 1-2 | 12 miles Zone 4-5 |
Choosing a Heart Rate Monitor
Chest Strap Monitors
Pros:
- • Most accurate, clinical-grade data
- • Reliable during high intensity
- • Works in cold/wet conditions
- • Better for intervals and sprints
Cons: Less comfortable, can chafe
Top picks: Polar H10, Garmin HRM-Pro, Wahoo TICKR X
Optical Wrist Monitors
Pros:
- • Convenient, always wearing watch
- • No extra gear to remember
- • 24/7 heart rate tracking
- • Good for steady-state running
Cons: Less accurate during intervals, affected by movement
Top picks: Garmin Forerunner series, Apple Watch Ultra, COROS
Recommendation: Use a chest strap for quality workouts where accuracy matters. Wrist HR is adequate for Zone 2 easy runs where precise data is less critical.
Heart Rate Variability (HRV)
HRV measures the variation in time between heartbeats—a key indicator of recovery status and autonomic nervous system balance.
Using HRV for Training
- • Higher HRV: Generally indicates good recovery, can handle hard training
- • Lower HRV: May indicate fatigue, stress, or illness—consider easy day
- • Track trends: Your personal baseline matters more than absolute numbers
- • Measure consistently: Same time, same conditions (morning, upon waking)
Apps for HRV: HRV4Training, Elite HRV, Whoop, Oura Ring, Garmin watches all track HRV and can guide training readiness.
Factors That Affect Heart Rate
Heart rate isn't just about effort—many factors influence your readings:
Factors That Raise HR
- • Heat and humidity
- • Dehydration
- • Caffeine
- • Stress and anxiety
- • Poor sleep
- • Illness (even mild)
- • Altitude
- • Accumulated fatigue
Factors That Lower HR
- • Improved fitness
- • Good hydration
- • Cool temperatures
- • Quality sleep
- • Low stress
- • Fresh/rested state
- • Beta-blocker medications
- • Acclimation to conditions
Practical tip: If HR is 10+ bpm higher than normal at the same pace, something is off. Consider an easier day or investigate causes (sleep, hydration, stress).
Understanding Cardiac Drift
Cardiac drift is the gradual increase in heart rate during prolonged exercise at constant pace. It's normal and doesn't mean you're working harder.
Causes of Cardiac Drift
- • Dehydration: Lower blood volume means heart pumps faster
- • Core temperature rise: Body works to cool itself
- • Glycogen depletion: Shifts energy systems
- • Heat dissipation: Blood diverts to skin
What to do: For long runs, start at the lower end of your target zone. Accept that HR will rise 5-10% over 60+ minutes. Don't chase a specific HR by slowing dramatically—the drift is normal.
Heart Rate vs Pace Training
| Workout Type | Use Heart Rate | Use Pace |
|---|---|---|
| Easy/Recovery Runs | Yes - stay in Zone 1-2 | Secondary |
| Long Runs | Yes - monitor effort | Allow variation |
| Tempo Runs | Reference | Yes - target pace |
| Intervals/Speed | Too slow to respond | Yes - hit target splits |
| Hill Workouts | Yes - pace unreliable | Meaningless on hills |
| Race Day | Elevated due to adrenaline | Yes - execute strategy |
Common Heart Rate Training Mistakes
1. Using Wrong Max HR
Formula-based max HR can be off by 10-20 bpm. All your zones will be wrong. Do a field test.
2. Running Zone 2 Too Fast
Most runners' "easy" pace is actually Zone 3. True Zone 2 feels embarrassingly slow. That's correct.
3. Ignoring HR Variability
HR is elevated in heat, when tired, stressed, or sick. Adjust expectations accordingly.
4. Using HR for Intervals
HR takes 30-60 seconds to respond to effort changes. It's useless for short intervals—use pace.
5. Obsessing Over Numbers
HR is a guide, not a law. If you feel terrible at "correct" HR, something else is wrong. Listen to your body too.
Sample Heart Rate-Based Workouts
Zone 2 Aerobic Builder (60 min)
Entire run in Zone 2. Start lower (62-65% max HR), allow drift to 68-70% by end. Can you talk? Good. Nasal breathing? Perfect.
Threshold Development (50 min)
15 min warm-up Zone 1-2 → 20 min Zone 4 (80-88% max HR) → 15 min cool-down Zone 1. Monitor HR response, not just pace.
Long Run with HR Ceiling (90 min)
Cap HR at 75% max. Walk hills if needed to stay under. Build aerobic endurance without accumulating fatigue.
Progressive HR Run (45 min)
15 min Zone 1 → 15 min Zone 2 → 10 min Zone 3 → 5 min Zone 4. Finish feeling strong, not depleted.
Frequently Asked Questions
What are the 5 heart rate zones for running?
Zone 1 (50-60% max HR) is recovery, Zone 2 (60-70% max HR) is aerobic base building, Zone 3 (70-80% max HR) is tempo, Zone 4 (80-90% max HR) is threshold, and Zone 5 (90-100% max HR) is VO2max/anaerobic training.
How do I calculate my maximum heart rate?
The most accurate method is a field test or lab test. Common formulas include 220 minus age (basic), 208 - (0.7 x age) (Tanaka formula), or 211 - (0.64 x age) for more active individuals. Field tests provide the most accurate personal results.
What is Zone 2 training and why is it important?
Zone 2 training (60-70% max HR) builds aerobic base by developing mitochondria, improving fat oxidation, and enhancing capillary networks. It should comprise 80% of training volume and is characterized by being able to hold a conversation while running.
Why is my heart rate high when running slow?
High heart rate at slow paces can indicate insufficient aerobic base, dehydration, heat, fatigue, stress, or caffeine effects. It may also mean your zones are calculated incorrectly. Building Zone 2 fitness gradually lowers heart rate at the same pace over time.
Should I train by heart rate or pace?
Both are valuable. Heart rate shows internal effort and adjusts for conditions like heat and fatigue. Pace shows external performance. Use heart rate for easy and aerobic runs, pace for speed work and races. Many runners use both together.