Summer is here, and race courses are heating up. While the obvious challenges of Ironman are the distances and difficulty of the swim, bike and run, one major barrier to summertime success can be heat and humidity. This builds as your race day progresses. Poor heat acclimation and hydration strategies can ruin even the best training preparation.
Your Heat Pre-Acclimation Plan
You can actually train your body to be able to ingest fluid more efficiently. A good goal is one liter per hour (1L = 33oz). That is two small bike bottles per hour. Drinking should be done regularly and systematically; if you forget and then “guzzle” to get the fluids in, it is more difficult to ingest. Hydration keeps blood plasma volume levels up, which is necessary for oxygen delivery to muscles and sweating.
The good news is you can pre-acclimate before your race. Three weeks out from your event plan 60-90 minute indoor sessions (bike or run) for five consecutive days. Turn up the heat and turn on a humidifier. Some athletes will ride in the bathroom with the shower running to get really steamy! Get very hot and let yourself sweat, riding at a moderately elevated heart rate. In the following two weeks repeat this activity 2-3 times per week (30-60 minutes is fine) to maintain acclimation.
Acclimation also reduces salt loss in sweat. On average, individuals that are heat acclimatized lower their rate of salt loss versus non-heat acclimatized individuals. In really hot conditions and at high sweat rates more salt will be lost. This too is highly individual and varies a lot. 500-750 mg sodium/liter of water is a good target, so you may need to add salt to your electrolyte drinks. 1/4 tsp of salt (sodium chloride) has 590 mg of sodium. If you use salt tabs, check sodium levels, which can vary between 50mg and 350mg per capsule.
Finally, plan your race outfit well ahead of time and make sure it is comfortable for a long day out there. A white or light colored uniform reflects heat, and a white mesh hat or sun visor keeps the sun off your head. Placing ice in your hat helps to keep core temperature down. Good sunglasses keep you relaxed from the sun’s glare, but do make sure there is some airflow for cooling, especially for the run.
Travel And Race Week Prep
What you do or don’t do during the days leading into Ironman, or any hot race, can have a profound impact upon your performance. To fully acclimate to an extreme change in climate you will have to arrive about 10 days prior to the event. While this may not be feasible or practical for some, arriving at least five days beforehand will allow your body to semi-adapt to the temperature and humidity and you will be far better off than flying in the day before. Once there, it may be tempting to jump out and get training in the heat of the day in hopes of speeding acclimation, but you will need to ease your body into this change to minimize stress. Don’t blow your taper! For the first couple days get up early for your taper sessions, before the heat hits. Minimize your time spent in the direct sun for the remainder of the day, but be sure to still spend short periods of time outside to aid your body’s adjustment. After these first couple of days try to do a few sessions at the hottest time of the day. The key here is not to overdo heat exposure this close to the race. For example, if you have a 30-minute run with some pick-ups, be outside for only 30 minutes and refuel/rehydrate immediately afterwards. When not outside, avoid air conditioning the best you can. This may be unpleasant to some, but it is key to speeding up heat acclimation. However, if the temperature is extremely high and you are having trouble cooling down or sleeping, turn the AC on a setting low enough just for comfort.
Hydration during the days leading up to the race can be just as crucial as race-day hydration. Starting right from the airplane trip or drive, have a water bottle with electrolytes on hand. Sip water and electrolytes throughout the days leading up. A good basic trick is to add a ¼ teaspoon of table salt to your water if you are stuck without a proper replacement drink. Monitor your urine color to make sure you are not over or under hydrated. It should be a nice light yellow, not completely clear, and not bright yellow. Add a little more salt than usual to your food race week. The extra sodium can help prevent heat related muscle cramps as well.
Weather forecasts, heat training camps and even the days leading up to the race cannot always predict or prepare you for the weather conditions on race day. For instance, in Kona you can count on the humidity being high, but the temperature can range between 75-100F (25-37C).
Rehydration needs will be dictated by sweat loss, which is highly individual. In Hawaii sweat loss most often will exceed 1L/hr (33oz/hr) and because the maximum rate of fluid absorption is about that, 1L is a good goal for fluid replacement. i.e. 250 ml every 15 minutes or 1 L/hr.
The bike in an Ironman is the crucial time for taking on fluids and calories on a schedule (all of which you have tested in training). Throughout the ride, keep your body cool and fueled. After the swim, start with water on the bike for the initial 10 minutes or so until your heart rate levels off, and to dilute the salt in your stomach if it was an ocean swim. At that point start your caloric intake. Generally, look at the course and try to anticipate the best times to drink on the bike. Learn how the wind predominantly blows, and anticipate sections of headwind and crosswind. Downhills or flatter sections are good drinking and eating areas as the heart rate drops slightly and it may be easier to control your bike. Find out where the aid stations are, this will be part of your plan for regular drinking and reloading stores. If you do find yourself fighting the course and unable to fuel, it may be advisable to slow down a little in order to safely take on calories. It is also advisable to always have a spare water bottle and gels, in case you miss an aid station or your special needs bag. If you do miss your special needs bag, or lose your nutrition (i.e. dropped water bottle), stop and retrieve it. The time lost doing this will be negligible, compared to the time lost from dehydration and caloric depletion.
In the transition from bike to run, remember to put on a mesh running hat or a visor, also take the time to apply sunscreen. Once out onto the run, you may feel invincible and motivated as you run through the cheering crowds. Do not get carried away; stick to your goal pace or even build into it. Generally you should pace the run more conservatively as the thermostat rises, at 10 to 15 seconds a mile slower than your regular goal pace. You heart rate runs higher in heat and humidity at a given pace.
Aid stations are located every mile along the way, with ice, electrolytes, sponges, fuel and water. Keep drinking electrolytes along the way, pour water over your head, stick a cold sponge in your race suit and ice in your hat. This will help keep the core temperature down, allowing your body to use its energy to propel you towards the finish line while keeping your body and organs cool. Once again, make sure that you take the time to fuel and keep cool. This may mean walking the aid stations, which is okay, as it is preferable and faster than a melt down later on in the race. If you find yourself walking, remember that the same principles apply. Keep cool, get the calories in and keep hydrating. If you are planning on running the whole marathon, remember the fastest way to run is to keep the first 20 miles controlled. If you have something left in the last quarter of the run, then try turning the pace up.
Once you cross the finish line, keep walking and monitoring your body. If you have any concerns, err on the side of caution and seek medical advice. Continue to hydrate with electrolytes, get out of the sun, have a cool bath, get off your feet and even lie down and elevate your legs if possible. Continue to graze on food and hydrate.
Race day can throw many curveballs. Be flexible, relaxed and confident in your ability with whatever may come your way. Whatever it is, remind yourself that everyone is out there tackling the same conditions. If you keep your cool and stay excited for the challenge, you’ll already have a competitive edge.
LifeSport head coach Lance Watson has coached a number of Ironman, Olympic and age-group Champions over the past 25 years. He enjoys coaching athletes of all levels. Contact Lance to tackle your first triathlon or to perform at a higher level. Find more tips on Twitter @LifeSportCoach.