Half Marathon Training: What Is Zone 4 / Threshold?
SUMMARY:
Zone 4 — around 87–93% of max heart rate, RPE 7–8 — is your threshold zone. It feels hard but controlled, sitting just below your redline. For half marathon training, it sharpens your ability to sustain pace, improves lactate clearance, and builds the toughness needed for race execution. In this guide, we’ll break down what Zone 4 running is, why it’s essential for half marathon runners, and how to use it smartly in your plan.
What Is Zone 4 Running?
Zone 4 running—often called the threshold zone — is where your fitness sharpens, your speed-endurance improves, and your race-day strength is built. Zone 4 is your threshold or lactate tolerance zone—where your body is working hard, but still in control. This is the effort just below your redline—sustainable for 20 to 60 minutes, depending on your fitness. For half marathon training, Zone 4 is key for boosting your threshold pace, improving stamina, and preparing you to run faster for longer.
How Zone 4 Feels While Running
Effort Level: Hard, 8–9 out of 10
Heart Rate Zone: 87–93% of Max HR
Breathing: Heavy and laboured — breathing rhythm is harder to control
Talk Test: Only a few words at a time, conversation is very limited
Pace: Around your half marathon race pace or slightly faster
Use the FLJUGA Heart Rate Calculator to find your exact Zone 4 range.
Heart Rate Zones (Max HR Based)
Here’s how Zone 4 fits into your complete half marathon training zones:
Zone 1 (68–73% of Max HR):
Very easy. Used for recovery, warm-ups, and cool-downs.Zone 2 (73–80% of Max HR):
Comfortable effort. Builds endurance and supports long runs.Zone 3 (80–87% of Max HR):
Comfortably hard. Tempo runs and stamina workouts.Zone 4 (87–93% of Max HR):
Hard, controlled effort. Threshold sessions and race-pace workouts.Zone 5 (93–100% of Max HR):
Very hard. Short, intense VO₂ max intervals.Find your training zones fast – use our free calculators!
Why Is Zone 4 Important for Half Marathon Runners?
Key Benefits of Zone 4 Running:
Raises Your Lactate Threshold
Increases the pace you can hold before fatigue forces you to slow down.Improves Speed-Endurance
Trains you to hold strong paces for longer distances.Sharpens Race-Day Strength
Zone 4 is close to half marathon race pace—perfect for simulating race conditions.Boosts Mental Resilience
Teaches you to stay focused and composed under race-like intensity.
How to Use Zone 4 in Your Training Week
Best practices for half marathon runners:
1–2 Zone 4 sessions per week in key training phases
Use for threshold intervals or steady state threshold runs
Combine with long runs to simulate race effort in the later miles
Example Zone 4 Workouts for Half Marathon Training
Workout 1: Threshold Intervals
15 min easy warm-up
4 x 8 minutes at Zone 4 with 2–3 min jog recovery
10 min easy cool-down
Workout 2: Continuous Threshold Run
15 min easy jog
30–40 minutes continuous at Zone 4 effort
10 min easy cool-down
Workout 3: Long Run Finish in Zone 4
90 min long run (Zone 2–3)
Final 20–30 min in Zone 4
Sharpen your race pace. Try these threshold sessions.
Common Mistakes with Zone 4 Running
Overdoing Zone 4—leading to overtraining and burnout
Running too hard—accidentally slipping into Zone 5
Skipping easy recovery runs between Zone 4 sessions
Ignoring progression—jumping into long Zone 4 runs too soon
Mini FAQ: Zone 4 Running for Half Marathon Training
Is Zone 4 the same as threshold pace?
Yes. Zone 4 targets your threshold pace—the effort just below your redline.
How often should I do Zone 4 runs?
Once or twice per week is ideal—always balanced with easy running and long runs.
What heart rate zone should I race a half marathon in?
For most runners, a half marathon is raced in the upper end of Zone 3, with stronger runners spending more time in Zone 4 during the final miles. Find your training zones fast – use our free calculators!
Can beginners do Zone 4 runs?
Yes, but start cautiously with shorter intervals and always include plenty of recovery.
Final Thoughts: Push the Edge, Build the Strength
Zone 4 is where you develop the controlled power needed to race your best half marathon. It’s not about going all out — it’s about training just below your limit, consistently and with purpose. When paired with easy miles, long runs, and solid recovery, Zone 4 becomes the sharp edge of your endurance. Respect it, use it wisely, and you’ll gain the race-day strength to push harder, last longer, and finish faster.
Ready to reach Zone 4 and boost your half marathon speed and endurance?
Always consult with a medical professional or certified coach before beginning any new training program. The information provided is for educational purposes only and is not a substitute for personalized advice.
