Getting Acclimatized to the Heat

Successful acclimatization takes about 7-10 days of training and living in a hot environment, so it isn't always possible to be fully adapted before racing in a hot climate. The advantage of living in a hot environment is that your body will adapt and allow you to train and race in the heat better than individuals from cooler climates. Most adaptations to heat that your body will go through are related to sweating. As sweat evaporates, heat is dissipated. In a hot and humid environment, the air is already saturated with water, and very little evaporation occurs. This is why hot and humid climates are the most difficult for competition.

The first adaptation is that your sweating threshold decreases. You will begin to sweat soon after starting exercising.

The second adaptation is a significant increase in sweating. Some athletes exercising in a hot and humid environment can lose up to two liters of sweat per hour.

Finally, the composition of your sweat changes with acclimatization to heat. The amount of sodium that is
lost through sweat decreases as you become adapted to the climate.

What can you do to prevent dehydration?

Adequate hydration, both before, during and after exercise can help you steer clear of dehydration. One of the biggest mistakes that novice racers make is drinking too much water immediately before the event. If you consume too much water in a short period of time, your body will lose an excessive amount of electrolytes (ie sodium and potassium) in urine. This is the first step in dehydration. Dehydration leads to cramping, decreased performance, increased heart rates and increased body temperature.

 Here’s how to avoid it:

1. Remain hydrated in the days before the event
2. Drink fluid replacement drinks containing sodium to replace electrolytes.
3. Drink one bottle of water or fluid replacement drink 2 hours prior to the race start
4. Drink another four to eight ounces 15 minutes before the race.
5. During events lasting greater than one hour, include both carbohydrates and sodium in your fluids.
6. If you will consume any gels, bars, or other food during the race - drink water.
7. Drink BEFORE you are thirsty. If you wait, you will already be moderately dehydrated - and have difficulty recovering during the event.
8. Continue to drink 6-10 ounces of fluid every 15 to 20 minutes throughout the race

You need to plan your fluid replacement strategy, and should drink according to a time schedule - rather than by thirst. Some racers set their watches to beep every 15 minutes to help keep them on schedule during the bike.

In an XTERRA, using a hydration pack on the bike makes drinking easier - since you can carry enough fluid for two or more hours of riding, and you can drink from a tube even while riding on moderately technical sections. During the run, it is often difficult to drink - but this is when it is most critical in a triathlon. By the run, the temperature outside is high - and most people tend to sweat more while running than while cycling. There are several other things that you can do to help keep you cooler during races in the heat.

1. First, wear light colored clothing!
2. A hat can help keep the sun off your head, and provides a great place to stash some ice and keep you cool while out on the run course!
3. Sunscreen has been shown to decrease the temperature of skin exposed to sun, so slap it on - and protect yourself from skin cancer while you're at it.
4. Make sure to ride in a helmet with adequate ventilation. Research has proven that helmets with good ventilation are even cooler than wearing no helmet at all - and they can save your life!
5. Finally, be prepared to go a little bit easier in the heat. Because heat is such a stressor, you may not be able to perform the same way you can in a cool climate.
6. Start out conservatively, and if you feel good two-thirds of the way through the race, then push it.

This is a good racing strategy in general, but can pay even bigger dividends in hot races when attrition starts to play a bigger factor in the outcome of the race.

 Neal Henderson is a PowerBar sponsored XTERRA Pro athlete, and is the Coordinator of Sport Sciences at the Boulder Center for Sports Medicine in Boulder, CO.