Marathon Training: What Is Zone 4 / Threshold?

MarathonZone 4 / Threshold
Written By FLJUGA

SUMMARY:
Zone 4 sits around 87–93% of max heart rate with an RPE of 7–8. It represents threshold running. It feels hard, focused and controlled. In marathon training, it helps increase your ability to hold effort just below your redline, improves lactate clearance and builds strength for surges, climbs and fast finishes. In this guide, we’ll break down exactly what Zone 4 is, how it feels and why it’s one of the most powerful tools in your marathon training plan.

Focused runner working through a threshold effort under bright race conditions.

Threshold Training Builds the Edge

Marathon success is not just about how far you can go. It is about how strong you can stay in the final 10K. That is where Zone 4 training becomes essential. You are not sprinting but you are working close to your maximum sustainable intensity. It sharpens pacing, improves form under pressure and teaches you how to stay strong when fatigue builds. Zone 4 is where stamina becomes strategy. Use it well and your marathon finish becomes faster and more controlled.

What Is Zone 4 Running?

Zone 4 is your threshold zone. It sits just below VO2 max and pushes you to hold a hard pace without losing control. It is challenging but manageable and it improves your body’s ability to process lactate during high-output running.

Zone 4 Defined:

  • Heart Rate: 87 to 93% of Max HR

  • Effort Level: 7 to 8 out of 10

  • Breathing: Deep and laboured

  • Pace: Faster than marathon pace but not an all-out effort

  • Duration: 10 to 30 minutes per interval or in structured blocks

This is where the body learns to tolerate discomfort. You are holding back just enough to stay strong throughout the rep. It is not about speed. It is about sustainability under strain.

Why Zone 4 Matters in Marathon Training

Threshold training is where performance and discipline intersect. For marathon runners, Zone 4 develops your ability to run hard without fading. It helps you manage lactate, pace evenly and maintain posture when others are breaking down.

Top Benefits of Zone 4 Work:

  • Raises Lactate Threshold
    Teaches your body to handle more intensity before lactate accumulation becomes performance-limiting

  • Improves Pacing Under Fatigue
    Conditions you to hold steady effort without slowing in the late miles

  • Builds Mental Control
    Sharpens focus and strengthens your ability to run through discomfort

  • Supports Race-Day Stamina
    Improves your capacity to work hard for long periods without crashing

  • Improves Running Economy at High Effort
    Trains your muscles and nervous system to stay efficient under stress

Threshold running is a cornerstone of race prep. It teaches you to be smart with effort and strong under pressure.

How to Use Zone 4 in a Marathon Plan

Zone 4 should be introduced only after building a solid base of Zones 2 and 3. It works best in the final six to ten weeks before your race when your aerobic foundation is already strong.

When to Use It:

  • During the peak phase of your plan

  • After rest days or easy recovery runs

  • Once per week to avoid overtraining

  • As part of a tempo session or progression run

You do not need high volume to see gains. Quality reps matter more than quantity in Zone 4.

Sample Zone 4 Sessions for Marathon Runners

These workouts build the stamina and strength needed to hold pace under pressure.

Option 1: Continuous Threshold Tempo

30 minutes steady Zone 4
Smooth pacing from start to finish
Good for developing control at marathon plus pace

Option 2: Cruise Intervals

4 x 10 minutes at Zone 4
2 minutes easy jog between
Improves lactate clearance and mental pacing

Option 3: Progression Run Finish

Easy Zone 2 for 45 minutes
Final 20 minutes in Zone 4
Simulates marathon fatigue and late-race intensity

Option 4: Long Intervals

3 x 15 minutes in Zone 4
3 minutes jog between
Focus on holding form and breathing under extended stress

Always warm up properly and finish with 10 to 15 minutes of Zone 1 jogging to recover.

How Do You Know You Are in Zone 4?

Zone 4 should feel like work, but not like survival. You are in control but close to your edge.

Key Indicators:

  • Heart Rate: 87 to 93% of max

  • Breathing: Strong and rhythmic but heavy

  • Effort: RPE 7 to 8 — challenging but maintainable

  • Mental State: Focused and alert

  • Form: Begins to weaken if you lose concentration

You should be able to hold the effort for several minutes but not speak more than a word or two. If you feel like you could go forever, it is not Zone 4.

Common Mistakes with Zone 4 Training

Threshold training is powerful when done correctly. Done wrong, it becomes draining or ineffective.

Avoid These Pitfalls:

  • Pacing Too Hard
    If you push into Zone 5, you miss the sustained benefits of threshold training

  • Not Recovering Enough Between Intervals
    Inadequate recovery ruins quality and leads to poor adaptation

  • Doing It Too Often
    Too much Zone 4 leads to overtraining and fatigue

  • Skipping Warm-Ups or Cool-Downs
    You need full prep and recovery to make threshold sessions effective

Zone 4 should be treated with respect. It is not just another workout. It is a skill session for racing.

Zone 4 vs Other Training Zones

Each zone supports a different part of the marathon puzzle. Zone 4 is where your racing skills are developed.

Use our free FLJUGA calculator to find your exact heart rate zones before you begin.

Why Elite Runners Train in Zone 4

Elite marathoners spend a lot of time in Zones 2 and 3. They use Zone 4 to prepare for race intensity. It is where they learn how to pace under pressure and hold strong through the hardest miles.

Elite Benefits of Zone 4:

  • Trains lactate tolerance

  • Builds confidence in race pace

  • Improves running economy at high effort

  • Reinforces mental control under fatigue

This is the difference between hanging on and kicking strong.

FAQs: Zone 4 for Marathon Runners

Is Zone 4 the same as race pace?
Most marathon pacing is built in Zone 2 with stretches that push into Zone 3. Some runners may reach Zone 4 in the latter stages of the race.

Can beginners train in Zone 4?
Yes but only after building a strong aerobic base. Start with Zones 2 and 3.

How often should I train in Zone 4?
Once per week is enough during race build-up.

How long should a Zone 4 rep be?
Anywhere from 8 to 30 minutes depending on experience and session type.

FURTHER READING: EXPLORE THE FULL MARATHON ZONE SERIES

Training Sessions:

Final Thoughts

If you want to hold your marathon pace with confidence, you need to spend time at threshold. Zone 4 sharpens your ability to run strong under pressure, stay smooth through fatigue and unlock new levels of performance. These sessions aren’t easy and they’re not meant to be. But they teach you how to stay composed when your legs are heavy and your breathing is deep. That’s what race day feels like in the final 10K.

The more controlled work you put in here, the more prepared you’ll be to stay focused and finish strong. Zone 4 is where fitness turns into race strength. Use it wisely and it will change how you run.

Are you ready to raise your threshold and run stronger for 26.2?

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.

FLJUGA
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