Half Marathon Training: What Is Zone 3 / Tempo?

SUMMARY:
Zone 3, around 80–87% of max heart rate, RPE 5–6, represents tempo running. It feels comfortably hard and rhythm driven. In half marathon training, it builds speed endurance, improves aerobic strength and prepares you to hold strong pacing over longer efforts. In this guide, we’ll break down what Zone 3 running is, why it matters for half marathon runners and how to use it safely and strategically.

Run Strong, Stay Smooth

You don’t race a half marathon in Zone 5. You race it with control and that’s exactly what Zone 3 teaches. This is where you develop your ability to hold a strong, steady effort for an extended time. It’s not about top-end speed. It’s about resistance to fatigue and staying sharp over distance. It teaches you how to stay composed, efficient and focused when the miles start to feel heavy. For half marathon runners, it’s where the race is won or lost.

What Is Zone 3 Running?

Zone 3 is commonly known as the tempo zone. It’s harder than a typical endurance run, but not as intense as a threshold or VO2 max session. You’re working, but in control.

Zone 3 Defined:

• Heart Rate: 80–87% of Max HR

• Effort Level: 5–6 out of 10

• Breathing: Strong and rhythmic

• Pace: Steady and challenging — talking becomes limited

Zone 3 isn’t an all-out push. It’s consistent work that tests your ability to hold form, manage discomfort and stay mentally engaged for longer periods.

Why Zone 3 Matters in Half Marathon Training

The half marathon is a test of pacing and endurance. It demands that you hold a strong effort without blowing up. Zone 3 running helps you build that exact skillset.

What Zone 3 Improves:

• Aerobic Power: Extends the ceiling of your aerobic system

• Fatigue Resistance: Teaches you to sustain effort without fading

• Running Economy: Reinforces efficient movement patterns under stress

• Mental Focus: Builds concentration and control over long stretches

• Lactate Clearance: Increases ability to clear byproducts and stay smooth

Zone 3 is the zone of discipline and every strong half marathoner needs that edge.

When to Use Zone 3 in a Half Marathon Plan

You’ll use Zone 3 during the mid-to-late blocks of your half marathon cycle. When endurance is established and you’re sharpening stamina.

Smart Uses of Zone 3:

• Midweek Tempo Runs: 20–40 minutes of steady Zone 3

• Progression Runs: Finishing long runs with 20–30 minutes in Zone 3

• Broken Tempo Sets: Intervals like 3 x 10 min with short jog recovery

• Simulation Days: Running at goal pace to lock in rhythm

Use it once per week or every 10 days, depending on training load.

How Zone 3 Feels While Running

It’s not easy, but it shouldn’t feel desperate either. Tempo effort should challenge your ability to stay composed, especially mentally.

• Heart Rate: 80–87% of max

• Talk Test: Can speak in short phrases only

• Breathing: Controlled but deep

• Fatigue: Builds gradually, not instantly

It’s the feeling of holding strong, not hanging on.

Sample Zone 3 Workouts for Half Marathon Runners

Here are two effective ways to use Zone 3 during your training week.

Option 1: Continuous Tempo Run

• 10 min Zone 1 warm-up

• 25–35 min continuous in Zone 3

• 10 min Zone 1 cool-down

• Focus: Pacing, breathing and form under sustained effort

Option 2: Tempo Blocks

• 3 x 10 min in Zone 3 (2 min Zone 1 jog between)

• Easier to recover from, still develops stamina

• Focus: Holding rhythm across multiple efforts

Both approaches build control, fatigue resistance and half marathon-specific endurance.

Common Mistakes with Zone 3 Training

Zone 3 is easy to get wrong if you rush the pace or neglect recovery.

Mistakes to Avoid:

• Going Too Hard: Turns it into a Zone 4 session, harder to recover from

• Skipping Zone 3: Many runners overdo speed or long runs, missing this sweet spot

• Underestimating the Effort: Zone 3 isn’t easy, it’s smart work that adds up

• Ignoring Form: Don’t let posture and stride break down, stay tall, smooth and strong

Use heart rate to guide your effort, especially on flatter terrain.

Zone 3 vs Other Training Zones

Each training zone has a purpose. Zone 3 is where aerobic development meets pacing control, ideal for half marathon racing.

• Zone 1 / Recovery (68–73%)
  Effort: Very easy
  Use: Recovery, warm-up, cool-down
  Check out: Running: What Is Zone 1 / Recovery?

• Zone 2 / Endurance (73–80%)
  Effort: Easy and steady
  Use: Base building and long runs
  Check out: Running: What Is Zone 2 / Endurance?

• Zone 3 / Tempo (80–87%)
  Effort: Comfortably hard
  Use: Tempo runs, fatigue resistance

• Zone 4 / Threshold (87–93%)
  Effort: Hard but controlled
  Use: Race pace prep, lactate tolerance
  Check out: Running: What Is Zone 4 / Threshold?

• Zone 5 / VO2 Max (93–100%)
  Effort: Very hard
  Use: Speed sharpening, short intervals
  Check out: Running: What Is Zone 5 / VO2 Max?

You can use our free calculator to find your exact zones.

Why Tempo Running Works for Half Marathon Training

Half marathon racing lives in the overlap between Zones 2, 3 and 4. That means the more time you spend training efficiently in Zone 3, the more race-ready you become.

Why Zone 3 Is Powerful:

• Pushes your aerobic limit upward

• Improves how you handle fatigue over time

• Develops psychological readiness for pacing and patience

• Helps smooth transitions from base phase to race-specific work

Tempo isn’t trendy, but it works. Elite and amateur runners alike use it consistently to build race-day performance.

FAQs: Zone 3 for Half Marathon Runners

How long should a tempo run be?
Start with 20 minutes and build to 30–40 as fitness improves.

How often should I do Zone 3 work?
Once a week is typical during mid-season. Twice if your recovery allows.

Is Zone 3 the same as goal pace?
For many runners, yes. Zone 3 often overlaps with half marathon pace.

What’s the best time of year to focus on Zone 3?
Mid-build or peak phase, after your base is set and before final race sharpening.

Further Reading: Explore the Full Half Marathon Zone Series

• Half Marathon Training: What Is Zone 1 / Recovery?

• Half Marathon Training: What Is Zone 2 / Endurance?

• Half Marathon Training: What Is Zone 4 / Threshold?

• Half Marathon Training: What Is Zone 5 / VO2 Max?

Training Sessions:

• Half Marathon Training: 10 Zone 3 / Tempo Workouts

• Half Marathon Training: 10 Essential Sessions

Final Thoughts: Train in Tempo, Race with Confidence

Zone 3 is more than a pace. It’s a mindset. It teaches you how to hold effort, stay in control and stay smooth under pressure. For half marathon runners, this is where you develop the skill of staying strong, not just starting fast or finishing hard. Train consistently in Zone 3 and your race-day confidence will rise with your stamina.

Ready to harness Zone 3 for your half marathon training?

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.