Read time: 7min.
By Coach Yan Busset
So, you're thinking about doing an Ironman? That’s a great challenge, and understanding what it takes will help you prepare for it properly. In 1978, a group of military men in Hawaii wanted to see who was the fittest: swimmers, cyclists, or marathoners. And naturally, they decided to settle it in the most "reasonable" way possible: by picking the longest and toughest races on the island and combining them into one! You know, just your typical weekend challenge.
They combined the Waikiki Roughwater Swim (3.8 km), the Around-Oahu Bike Race (180 km), and the Honolulu Marathon (42.195 km) to create what we now know as the Ironman.
Understanding this race's demands is key to success. Let’s break it down so you can approach and reverse engineer each part of the race, so you can train for it with confidence. How much it takes for the average finisher to complete each segment, how many calories you burn, what are the limiters, the mental game it takes, and the goal you need to keep in mind in order to nail it.
The Swim (3.8 km / 2.4 miles)
Average Finisher Time: 1 hour 20 minutes (or 1/3 of "The Fellowship of the Ring" movie, just so you realise how long it takes)
Calories: 850 calories (or about 3-4 Hawaiian pizza slices, sorry for the pineapples)
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The swim in an Ironman is not just about covering 3.8 kilometers; it’s about swimming efficiently while keeping enough energy for the rest of the race. It’s about swimming in open water, which can be cold or choppy. This is very different from the calm of your local pool lane. You’re surrounded by other swimmers who all aim at the same buoy. You will be dealing with water temperature, visibility, and constant direction checks.
Limiters: The key limiters in the swim are technique and mobility. Poor technique leads to wasted energy, while limited mobility can cause fatigue, especially with the added resistance of the wetsuit.
Mental Game: Swimming in open water can bring anxiety, particularly due to the difficulty of managing your breathing in unfamiliar or rough conditions. This is why it’s important to be "race ready," practicing, if possible, in a group to maintain calm and focus, no matter what. Mental preparation is key to managing this anxiety and staying in control.
Goal: Your goal for the swim is to maintain a relaxed, efficient stroke while swimming as straight as possible without your usual pool lanes. Losing energy or swimming off course can cost you precious time and effort. Don’t underestimate the swim; getting it right sets the tone for the rest of the race.
The Bike (180 km / 112 miles)
Average Finisher Time: 6 hours 30 minutes (or "The Fellowship of the Ring" plus "The Two Towers," and halfway through "The Return of the King")
Calories: 4,500 calories (about 18 Hawaiian pizza slices)
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The bike is the longest part of the race and often the one where you can make mistakes that will cost you a lot of time on the marathon. It’s not just about completing 180 kilometers. "Bike to run": it’s about arriving at T2 with enough energy to tackle a marathon. You’re riding solo in an individual time trial, which means no drafting off other competitors. Pacing is crucial, and surges will burn energy you can’t get back. Every effort must be controlled, especially considering you still have the run ahead.
Nutrition is also a huge factor. The bike is a long “picnic buffet,” where you need to fuel for success. It’s essential to train your gut to handle as much calorie intake as possible during your preparation to avoid any gastric issues on race day.
Limiters: The key limiters here are endurance and strength. You need to develop aerobic efficiency to become a fat-burning machine and stay within your limits for hours. Building muscular endurance is crucial to handling the demands of the bike without fatigue.
Mental Game: Mentally, the bike segment can be tough simply due to its length. You need to stay focused and disciplined, especially as you’re static in one position for so long. This discomfort requires mental resilience. Your ability to maintain focus for safety but also to nail the nutrition and pacing will be the key.
Goal: Your goal on the bike is to focus on your plan. Stay in an aerodynamic but comfortable position that you can hold for the entire race. Conserve energy for the marathon, and don’t be tempted to push too hard early on. Many are so happy to have completed the swim that they get overexcited on the bike and push too hard. Remember, every surge burns a match, and you don’t want to run out before you hit the run.
The Run (42.2 km / 26.2 miles)
Average Finisher Time: 4 hours 50 minutes (or "The Fellowship of the Ring" and most of "The Two Towers")
Calories: 3,500 calories (about 14 Hawaiian pizza slices)
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The marathon in an Ironman is not like a regular marathon. After 180 kilometers on the bike, your legs may feel fresh due to the change in position, but that’s a trap. Hold your horses at the beginning, as the race really begins between the half marathon and kilometer 30. Everything before that is a warm-up, and if you push too soon, you’ll hit the wall.
Ironman is an energy management race. Your body has a limited store of carbohydrates, and you burn through more than you can replenish during the race. Training should reflect this, as you need to become more efficient at conserving energy. Strength training is also essential because by the end of the marathon, your body needs the strength to carry itself through.
Limiters: Running economy and strength are the key limiters. Running on tired legs after the bike is not like your Sunday local park run.
Mental Game: The run is where the mental battle truly begins. It often starts off easy due to the change of position, but as the race goes on, it becomes more and more "heavy." Mentally break the marathon into smaller segments; each aid station becomes a small victory. When the inevitable dark moments come, regroup, slow down, eat, and keep moving. Your body is capable of far more than you might think during those tough moments, and your willpower will be what gets you through. One step at a time.
Goal: The goal on the run is to maintain the energy management mode, steady pacing, and good nutrition. You may not be able to take as many calories as on the bike, but you still need them to reach the finish line. At this point, you are almost there—"Just a marathon to go." It’s a funny thought but a great motto.
Reverse engineering
So when you decide to sign up and prepare yourself for an Ironman, think of these as your end goal: assess what technique skills you have currently in the three sports, what is the longest distance you have completed so far, and what time you can dedicate to training. No rush there. Keep in mind that to be "Ironman ready" it can take 1-3 years, as you need to be progressive in your training regime if you want to avoid overtraining and injuries. Also, I would recommend that you train your "ABC" as a triathlete over shorter distances first, rather than jumping on a full distance first. Of course, the reward of becoming an Ironman finisher is priceless, but the main value of the overall experience is most probably more on the habits you will have to build to raise your fitness to the height of the challenge. It’s a transformative journey that is a lifetime gift.
Practical and Applicable Tip: The Ultimate Readiness Test
Before race day, it’s important to assess whether you’re truly prepared for the Ironman. About four to six weeks before your event, plan a big training day. This simulation can help you gauge if you’re ready and finalize details of your race plan.
Start with a one-hour swim, simulating the race start.
After a break (30min-1h), move on to a five-hour bike ride, focusing on race pacing and nutrition.
Take another break (30min-1h), then finish with a two hour run.
You should be able to tackle this test without significant issues. If you can manage this training day smoothly, it’s a great sign that you’re ready to complete the full Ironman.
Breaking down the Ironman into its individual segments and understanding the specific demands of each one will help you approach your preparation more effectively. When you decompose the race like this, it becomes less overwhelming; you can focus on each part and what it requires. For many, an Ironman may seem like the challenge of a lifetime, but it’s absolutely doable if you dedicate time and maintain the discipline to train for it.
Adaptation to race conditions is also key. Whether you're racing in a hot environment and need to train for heat adaptation or preparing for a hilly or flat course, your training must reflect the specific challenges of your race.
The goal for your first Ironman shouldn’t be about chasing a specific time; it’s about finishing the race and learning what the experience is like. With proper pacing, nutrition, and the right mindset, you’ll be able to cross the finish line and achieve something amazing. Remember, you don’t need to be a Superman to be an Ironman: with the right preparation and mindset, you can cross that finish line and achieve something truly remarkable.
The averages used in the article are based on the following data:
Average Time: The average finish time for men in an Ironman is approximately 12 hours, and for women, it’s about 13 to 14 hours. For simplicity, we used an average of 12 hours 40 minutes for both. So about the equivalent to watch the "Lord of the Rings" trilogy…twice!
Average Calories: Completing an Ironman burns approximately 8,000 to 10,000 calories (it varies according to, among other factors, your metabolism, your pace, your preparation). The estimate used here is 9,000 calories, split across the swim, bike, and run. Not that I'm asking you to switch energy gels and go for pizza, but it’s just a fun comparison so that you can easily picture the energy demand of such an event. An average slice of Hawaiian pizza is estimated to contain about 250 calories. So about 4.5 pizzas. Bon appétit!
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