Pro triathlete and doctor Tamsin Lewis on how to race in Ironman Hawaii.

Every year in October, thousands of the world’s best Ironman athletes arrive in Kona, Hawaii, for the Ironman World Championships. Before getting the chance to race here, every single one of them had to qualify by finishing near the top of their category at an Ironman event earlier in the year. So they know what they’re doing.

But although the race in Hawaii covers the same Ironman distance (3.8km swim, 180km bike, 42.2km run), it’s a very different beast to other events. As if the stifling humidity and brutally high temperatures aren’t enough, they’re sometimes accompanied by strong crosswinds on the bike. These issues can create a number of problems for even the most experienced athletes.

And when you consider that of the 1,800-odd highly trained athletes that take part in Ironman Hawaii, 15-20 per cent of them end up in the medical tent, you realise just how serious those problems can be.

In 2010, I was allowed to look around the medical tent and was intrigued to see the number of athletes hooked up to drips and looking barely conscious. All of them had finished in under 10 hours – a respectable performance in Kona – yet they were barely able to remember their own names.

I was in Kona again in 2012, this time as a volunteer medic on the race staff, which meant I could attend the Ironman Sports Medicine Conference. It’s held during race week and it’s where some of the most-informed medics in the world present the latest research. It’s also where volunteer medics learn how to tackle the medical problems most likely to arise on race day.

These lessons, along with my experience as a volunteer medic, gave me a valuable insight into the challenges athletes face at Ironman Hawaii. So if you dream of tackling this famous race, there are two things you need to know how to handle: the heat and your nutrition. Get a firm grasp on these two, and you’ll be prepared and able to perform well in the challenging Hawaii environment.

Lesson 1: Beat the heat

Heat exhaustion is what Paula Newby-Fraser famously exhibited as she collapsed in the finishing stretch of the 1995 Hawaii Ironman. The early warning signs may include irritability, confusion, apathy, emotional instability and irrational behaviour. Giddiness, extreme fatigue, and vomiting can also be precursors. Athletes suffering from heat exhaustion also experience chills and get goose pimples, which is a sign their circulation is shutting down.

Hyperventilation may also occur – another of the body’s methods of cooling down. Poor coordination and staggering, or “running like a puppet on a string” are late signs and can be followed by collapse, seizure and/or coma.

Hawaii Prescription: 

  • Hydration

Good hydration helps prevent heatstroke but there’s no advantage to consuming more fluid than you’re losing. Weigh yourself before and after a simulated race session to calculate your fluid loss. Some experts believe that drinking too much fluid after endurance events can dilute the sodium in your blood.

  • Train in the heat

You need to acclimatise to exercising in the heat if you want to race well in it. Start gently and slowly build your sessions in the heat. You need a good fortnight, at least, for the acclimatisation process to take place, which involves your body retaining more water and salt, and increasing blood volume so your heart pumps more blood at a lower rate. ‘Heat-fit’ athletes also start sweating sooner but their sweat is of a weaker concentration. They also sweat in greater volume and over more of their body to help them stay cooler.

  • Get lean

Fatter athletes are more prone to heatstroke. This is simply because the extra fat is extra load, which takes more effort to move and so increases your exertional heat production.

  • Keep cool

Wear a ventilated helmet, hold ice in your hands or under your hat, or put sponges soaked in cold water in your top or shorts.

  • Use waterproof sunscreen

Sunburnt skin doesn’t sweat well, and sweating is vital for keeping cool.

Lesson 2: Fuel up right

Many of the athletes wound up in the medical tent because they got some aspect of their nutrition wrong and ended up losing a lot of weight – both water and fat. Some athletes lose as much as 8kg. Records show that the stronger the winds at Hawaii (a key part of the bike course), the higher the number of admissions to the medical tent. In windy conditions, riders typically don’t like to let go of their bars, tense up, use more energy and forget to eat and drink. So while their energy output is higher, energy input is reduced and soon becomes insufficient.

Athletes competing in the heat can sweat between two and six litres an hour, and most athletes drink less than they sweat so they start to dehydrate. And as their level of hydration drops so does their bodyweight –and a drop of just 2 per cent from dehydration is enough to impair performance.

Hawaii Prescription:

  • Fuel and hydrate on the bike

Find out what works for you by practising! By fuelling well you’ll be sparing your glycogen stores for when you really need them on the marathon. Get a hydration system with a tube on your aerobars so you can drink without taking your hands off the bars.

  • Pace yourself on the bike

Endurance training makes the body more efficient at burning fat as a fuel to higher relative heart rates. By riding at an intensity you’re accustomed to from training, you’ll burn more fat than glycogen. But remember, your heart rate will be higher for same effort due to the heat, so you’ll need to take on more carbohydrate than usual.

  • Train your gut

When your training is at its peak, allocate one session a week to practise your race nutrition strategy. Your gut is an organ and can be trained in the same way as any other muscle. Any endurance athlete knows that working out a nutrition strategy is essential for race day, but how many actually test that strategy in simulated race sessions?

  • Salt and cramping

Research is inconclusive, but most people who take extra salt experience reduced cramping during an Ironman. Clues to salt depletion include visible salt on your skin, sweat stinging your eyes and a salty taste in your mouth. The key is to experiment with extra salt in training, so you’re not trying anything new on race day.

Avoid the 3 B’s of Hawaii

Beware of bloating, burping and barfing. They’re all signs that your race preparation leaves a little to be desired

  • Be well trained for the race
  • Get acclimatised to the heat
  • Keep cool
  • Drink/eat a little and often
  • Train to eat and drink while racing
  • Start exercising with some fluid in your stomach
  • Avoid high-fibre foods before exercise – especially in the final 48 hours before racing
  • Keep your calorie intake between 200-400kcal/hr (calculated as per your bodyweight)
  • Don’t overdo it – if you start to suffer any of the three Bs, reduce the intensity of your effort until the symptoms subside
  • Minimise or completely avoid the use of anti-inflammatories (such as ibuprofen or aspirin) as they can irritate your gut