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Home / Training / Long distance / Ironman triathlon: how to pace it

How to pace your first Ironman

Got your first Ironman coming up and, and worried you're going to mess it up from the off? Tim Don explains how to pace it so you avoid a DNF disaster

Credit: Korupt Vision

Some say that pacing is an art, but in Ironman it’s more a skill… and a bloody tough one at that! Yet these are skills you can learn from via your training and shorter races, or even race scenario-type brick sessions. So, if you’re practical about it, you can nail it!

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If you’re doing an Ironman and you’re worried about the correct pacing, I’m guessing you don’t just want to finish the race, but also have a goal time and position in mind. That’s the key and the start of your pacing strategy.


With your coach, or if you’re self-coached with some of the data you’ll have gained from consistent training, you’ll be able to make a pretty good guesstimate for your swim, bike and run speeds, paces and HR or power. There are also great websites out there (such as Best Bike Split and Windsock) that can help predict your bike time and that you can add into the equation.


With pacing also comes fuelling, and this can affect your pace badly if you don’t stick to your pre-determined fuel/hydration plan for the bike and run. It goes without saying that you shouldn’t try any new products for the first time in the race, no matter how good someone says they are! Stick to what you’ve tried and tested, and also to the same schedule, that you’ve tried in training; once you nail that you can then think about the pacing of the race.


In Ironman, it’s always better to be more conservative with your pacing as something can always go wrong. It’s a long day so keep some energy left for the last 30-40km of the bike and 10-15km of the run.


On the bike I use a power meter. Me and my coach normally break the 180km bike leg down into segments. For Ironman South Africa this year, it was the first 50km to the turnaround then the next 20km with a killer headwind, before the uphill with a headwind then the downhill back to the start of lap two. And then repeat. (Unfortunately, at about 135km, I had a mechanical that couldn’t be fixed; gutted is an understatement but that’s another story!) I also have to keep an eye on the other main players who are with me or I can see at any U-turns. Luckily, I was below all my planned powers, so instead of being an early-race hero and sitting on the front into the headwind or trying to drop everyone, I was more than happy to save up some of my energy for the marathon run.


Also aim to focus on hydration, fuelling and looking after your body. Stretch your back out and give your legs a good, old shake out on the fast downhills, as well as thinking about being as aero as possible on the faster sections of the course to try and save even more energy.


Once on the run, you can really use the wind to your advantage (if the weather conditions allow you to do this), getting your speed up on the tailwind sections and keeping your cadence up into the headwinds. If anyone is around you at the same time, try and take a little bit of shelter or drop behind them before you hit the headwind section.


I use current heart rate and average pace per/km for the run. But, as I’m also racing for the win in the last 10-12km, I have to make decisions that might not be 100% to plan. Yet that’s racing and, with all my experience of being an old racing dog (!), I can have the upper hand. So always have a pacing plan B if things don’t go to plan.


The golden rule is to listen to your body. Sometimes it just feels great and, well, sometimes it’s telling you to slow down and it feels awful. So have confidence in your race plan and pacing goals. Really believe that, through all your training and hard work, you can go out and try and execute the best race-day performance you have in you. And remember that power and speed are nothing without control. Good luck!

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The 220 Triathlon team is made up of vastly experienced athletes, sports journalists, kit reviewers and coaches. In short, what we don't know about multisport frankly isn't worth knowing! Saying that, we love expanding our sporting knowledge and increasing our expertise in this phenomenal sport.