Half Marathon Training: What Is Zone 4?

Ready to enhance your half marathon fitness by hitting the threshold zone?

Zone 4 running—often called the threshold zone—is where your fitness sharpens, your speed-endurance improves, and your race-day strength is built.

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 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:

• Effort Level: Hard, 8–9 out of 10

• Breathing: Heavy, talking is difficult

• Talk Test: Only a few words at a time

• Pace: Around your half marathon race pace or slightly faster

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:

1. Raises Your Lactate Threshold
   Increases the pace you can hold before fatigue forces you to slow down.

2. Improves Speed-Endurance
   Trains you to hold strong paces for longer distances.

3. Sharpens Race-Day Strength
   Zone 4 is close to half marathon race pace—perfect for simulating race conditions.

4. 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

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: Zone 4—the Half Marathon Performance Zone

Zone 4 is where you sharpen your half marathon fitness—raising your threshold, improving stamina, and building race-day strength.

By using Zone 4 workouts carefully and combining them with a solid base of easy running and long runs, you’ll train smarter, race faster, and finish your half marathon with strength.

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.