Marathon Training: What Is Zone 5 / VO2 Max?
SUMMARY:
Zone 5 — around 93–100% of max heart rate, RPE 9–10 — is your VO2 max zone. It feels intense, sharp, and maximal. In marathon training, short sessions in this zone increase oxygen efficiency, and develop the speed reserve that makes race pace feel more manageable. In this guide, we’ll explain what Zone 5 running is, how it boosts marathon performance, and how to use it without risking burnout.
What Is Zone 5 Running?
Zone 5 training is where you unlock your VO2 max potential. It’s short, intense, and massively effective when used strategically in your marathon prep. Zone 5 is the VO2 max zone—the highest intensity you can sustain briefly. Your heart is near max output. You’re breathing fast. Your legs are burning. This is where you build top-end speed and oxygen delivery capacity. Even though a marathon is mostly aerobic, Zone 5 primes your system for strong finishes, surges, and race-day resilience.
How Zone 5 Feels (Marathon Training)
Heart Rate: 93–100% of Max HR
RPE (Effort Level): 9–10 out of 10
Breathing: Maxed — rapid, gasping for air
Talk Test: No speech possible
Pace: Much faster than marathon pace — short, controlled bursts
Find your Zone 5 heart rate — Try here.
Heart Rate Zones (Max HR Based)
Here’s where Zone 5 fits within your marathon training intensity guide:
Zone 1 (68–73% of Max HR):
Recovery and warm-up zone. Used often, never ignored.Zone 2 (73–80% of Max HR):
Easy aerobic effort. The foundation of marathon training.Zone 3 (80–87% of Max HR):
Tempo and race-specific efforts. High aerobic development.Zone 4 (87–93% of Max HR):
Threshold workouts. Lactate clearance and stamina building.Zone 5 (93–100% of Max HR):
VO2 max training. Short, sharp efforts to increase speed and oxygen efficiency.Not sure what pace to train at? Our Zone Calculators make it easy!
Why Zone 5 Training Helps Marathon Runners
Key Benefits of Zone 5 Running:
Increases VO2 Max
Boosts your body’s ability to use oxygen at high intensities.Improves Running Economy
Trains your body to run faster with less energy.Enhances Speed Reserve
Makes marathon pace feel easier by lifting your top-end potential.Supports Strong Finishes
Teaches your body to surge, kick, and stay smooth under fatigue.
How to Use Zone 5 in a Marathon Training Plan
1 session every 10–14 days
Ideal during speed phases before peak mileage blocks
Keep intervals short (1–3 minutes) with full recovery
Always follow with easy Zone 1/2 running the next day
Example Zone 5 Workouts for Marathon Training
Workout 1: VO2 Max Intervals
15 min easy warm-up
6 x 2 minutes at Zone 5 with 2–3 min jog
10 min easy cool-down
Workout 2: 30–30 Speed Play
20 x 30 seconds fast, 30 seconds easy
Light, race-friendly, and fun—great for sharpening
Workout 3: Hill Power Sprints
8 x 45 seconds up a steep hill
Walk/jog recovery down
Builds power, form, and aerobic demand
Want 10 Zone 5 marathon sessions to boost top-end speed and control? Try here.
Common Zone 5 Mistakes
Doing too much—Zone 5 is high-risk, high-reward
Using Zone 5 too early in your marathon cycle
Forgetting recovery — every VO2 max session demands rest
Letting ego push pace too hard—use HR, not feel, to stay precise
Mini FAQ: Zone 5 for Marathon Training
Is Zone 5 useful for marathoners?
Yes — but it’s a tool, not a foundation. It sharpens speed and supports finishing strength.
How often should I use Zone 5?
Once every 10–14 days is enough. Prioritise recovery between sessions.
Is Zone 5 the same as sprinting?
Not quite. Zone 5 is anaerobic, but not all-out sprinting. It’s intense, lasting 1–3 minutes—hard but still repeatable with rest. Sprints are shorter, sharper, and less sustainable.
Do elite marathoners train in Zone 5?
Yes. It boosts VO2 max, raises speed ceiling, and enhances pacing flexibility late in races.
Final Thoughts
Zone 5 isn’t where your marathon is raced—but it’s what helps you finish fast, push through tough moments, and lift your entire training ceiling. Use it sparingly. Pair it with a strong aerobic base and watch your performance sharpen as race day approaches.
These sessions aren’t about volume — they’re about precision. Just a few minutes at this intensity can drive major gains in speed, oxygen uptake, and mental sharpness. When added at the right time, Zone 5 gives you the ability to surge, to respond, and to hold form when the race starts to hurt. It’s not about going hard all the time. It’s about knowing when to go hard and making it count.
Ready to boost your VO2 max and finish your next marathon stronger?
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.
