How to Pace an IRONMAN 140.6 for Your Best Performance
A well-executed pacing strategy is one of the biggest factors in IRONMAN success. The best athletes know their limits, stick to their plan, and resist the urge to go too hard too soon. In a 140.6-mile race, poor pacing decisions will come back to haunt you. Here’s how to pace each discipline for your strongest possible race.
IRONMAN Swim: Start Smart, Stay Controlled
The 3.8 km (2.4-mile) swim is a huge challenge, but it’s just the beginning of a long day. You need to balance speed with energy conservation to set yourself up for a successful bike and run.
How to Pace the Swim
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Stick to a steady effort: Use Rate of Perceived Exertion (RPE) instead of constantly checking your watch.
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Aim for “strong but controlled”: You should feel like you can maintain the effort for much longer than the distance.
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Start slightly harder if you're a fast swimmer: If aiming for sub-10 hours (men) or sub-11 hours (women), swim slightly faster for the first 300-400m to clear the crowds, then settle into your goal pace.
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Use drafting to save energy: Swimming behind or slightly to the side of another swimmer can save up to 10% energy—make sure they are swimming the most efficient line!
Common Swim Pacing Mistakes
❌ Going out too hard and fading – leads to exhaustion before the bike even starts.
❌ Following the wrong swimmer – who is zigzagging or not the right pace for you.
❌ Not staying relaxed – tension wastes energy; stay smooth and efficient.
IRONMAN Bike: The Most Important Part of Your Pacing Strategy
The 180 km (112-mile) bike leg is where smart pacing makes the biggest difference. Push too hard, and your marathon will become a survival shuffle. Ride with patience and discipline, and you’ll finish strong.
How to Pace the Bike
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Use a power meter if possible: This is the best way to control effort.
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If no power meter, use heart rate and RPE
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Be consistent: Avoid surging and big power spikes—these burn extra energy and hurt your run.
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Control effort on hills: Many athletes push too hard on climbs without realizing it. Use easier gearing and maintain an even effort.
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Expect others to pass you early on: Let them go. Many will fade by mile 80 while you stay strong.
Common Bike Pacing Mistakes
❌ Going too hard too soon – leads to a slow, painful run.
❌ Uncontrolled effort on hills – avoid burning extra energy.
❌ Ignoring your fueling plan – stay fuelled on the bike to stay strong for your run.
Pacing yourself properly on the bike will help you run faster and feel fresher and more energized.
IRONMAN Run: Survive, Then Thrive
By the time you start the marathon, your body is already fatigued. The key is to start conservatively and stay steady. The best possible outcome is maintaining a consistent pace without fading or walking excessively.
How to Pace the Run
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Start at an easy pace: Your goal is to avoid slowing down. Start slower than you think you should.
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Use all three pacing tools: RPE, Heart Rate, and Pace, as none are reliable in isolation. Many variables can affect them, such as wind direction, gradient, and cardiac drift (increased heart rate due to heat stress).
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Hold back until halfway: If you feel strong at mile 13, you can gradually increase your effort.
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Use aid stations wisely: Walk if necessary to get fluids in, but keep moving forward.
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Expect mental challenges: Positive self-talk and breaking the run into small segments can help.
Common Run Pacing Mistakes
❌ Starting too fast – feels good at first but leads to a massive slowdown later.
❌ Not adjusting for conditions – heat, wind, and fatigue all affect pacing.
❌ Skipping nutrition – lack of calories and fluids can cause an energy crash.
🔗 Triathlon Race Pace Calculator
A well-planned race pace strategy can make or break your triathlon. Proper pacing helps you stay strong, avoid fading, and improve hydration and nutrition absorption. Use our race pace calculator to plan your pacing based on actual fitness, not guesswork. It works with thresholds like Functional Threshold Power (FTP), Pace, or simple Rate of Perceived Exertion (RPE) (1-10 scale).
Fitness Tests
Ensure you base your Full-Distance Triathlon pacing strategy on real results from fitness tests done within the last eight weeks. DO NOT GUESS!!!
Fitness Tests To Determine Your Thresholds
Final Thoughts: Pacing is Everything
Your IRONMAN race isn’t won in the first hour—but it can be lost there. Stick to your pacing strategy, trust your training, and run your race. Remember:
✅ Swim steady and controlled – don’t waste unnecessary energy.
✅ Bike with patience – this is the key to a strong run.
✅ Run smart – start slow, stay steady, and only push if you can in the final miles.
Pacing is the difference between finishing strong and struggling to the line. Get it right, and you’ll have your best IRONMAN yet!
Copyright MyProCoach™ Ltd © May 2018. All rights reserved.
Comments
1 comment
I read an article about pacing an Ironman about 7 years ago. It said to swim a comfortable pace then on the first hour of the bike go slow, let people pass you then find your pace and the last 6 miles you will be finishing strong. It's worked well for me finishing on the podium and winning my AG last year at IMMD. Kona bound.
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