One of the major differences between our sport and most other sports is that the duration of the race is so long that many of its competitors will have to perform in the heat of the day. Take for example the Olympic marathon which is usually run during the heat of the day. This is the total opposite from your standard marathon that starts at 7:00 or 8:00 AM. For this reason the Olympic marathon is an unpredictable race, and it is usually never won by the race favorites. Your typical world record holder who can beat everyone in 60-degree weather may not be able to perform as well if he/she does not do proper heat acclimation and acclimatization training and ignores all the complications associated with the heat. In triathlon where the majority of the racing is done in the summer and the running portion of the race is at the end of the race when it is even hotter, heat acclimation and acclimatization are a way of life. First let's explore what happens to your body when the temperature is high and you exercise. Then we will see how much of one's ability to deal with heat is genetic and what can be trained. Finally we will detail some of the things that anyone can do to improve their ability to perform well in the heat. 

The human body is a very adaptable system. Even while we are going about our daily lives our organs and brain are processing information. Things like minerals, water, temperature and many other things are constantly being checked. All the information is processed and action taken. Excess minerals are expelled, sugar levels are maintained by the liver, and our body controls the blood flow to many organs for proper function and to maintain temperature. This process is sometimes referred to as homeostasis. It is the ability for the body to react to feedback on certain conditions in order to maintain healthy overall functioning. There are limits to what the body can do, of course, but when it comes to handling heat and body temperature we will find that training and proper acclimatization can help the body with this task.

Remember the last time you ran at noon in the heat, perhaps during your lunch hour? It was hot and your heart rate was higher than normal, not to mention the shirt and socks were soaked afterwards. What happened during your run? What did your body do different this time as compared to a cool morning run. Let us explain the process that happens in heat training. As one begins to exercise in the heat, the brain begins to process all the signals, which include increased temperature due to the environment and exercise. There are two main demands that the body needs to deal with at this time. One is maintaining proper body temperature. Sending more blood to the skin capillaries for cooling purposes and activating the sweat glands begins the cooling process. The other demand caused by our exercising is supplying enough oxygen carrying blood to the muscles to maintain the demand for energy for the exercise.

As you can see, both of these require our precious blood. What is the body to do with a fixed supply of blood? The answer is of course increase the rate at which the heart is pumping the blood. The other possible solution is to limit the blood from going to other organs that are not critical. This point is really important to triathletes. If the body starts to not send blood to the digestive system, any food we take may not get digested. This is the reason I recommend triathletes not eat solids during races. Blood is required for your stomach to process foods and digest it. If blood is not in good supply and you eat solids then they can very possibly sit on your stomach and cause GI problems. There is only a fixed amount of blood to go around. Something has to give and this is one reason why there are so many GI problems during long hot races. But that's a topic for another time. Back to our hot weather workout.

Once the additional blood reaches our skin for cooling purposes, our body activates all the sweat glands to moisten the skin. As the water evaporates from the skin, it takes away the heat and cools the blood. The more evaporation occurs the more cooling will take place. One problem with this cooling process occurs when the ambient humidity is high. If the humidity is high then there is very little evaporation and very little cooling. You will sweat and sweat until you either slow down or dehydrate. That brings a very important aspect, which is hydration. As a triathlon gets longer, hydration becomes very important. Each athlete needs to know how much they sweat and how much to drink to replenish the water and minerals lost in exercise. Performance can deteriorate very rapidly even in a short session. Blood thickens due to dehydration as blood plasma is reduced. If the blood is thick then your heart cannot pump it as fast. This will start a chain reaction that will have you walking in no time and most likely send you to the medical tent if not risk your life. Remember Lance Armstrong at the one-hour time trial during the tour de France? He forgot to hydrate during warm up in a hot day. Even a professional like him cannot ignore the basic principles of exercising in the heat. There is only so much the body can do.

So far we discussed what happens on a hot day during exercise and we discussed how the body uses blood to cool itself. We also discussed how the body takes away blood to other organs like the stomach, which can cause GI problems when the food sits unprocessed in the stomach. Additionally we discussed how hydration is important in order to replenish fluids and minerals to keep the cooling process working properly. There is one more item related that needs to be discussed.

 Remember that so far the solution to the demand for blood was to pump more and also take it away from organs that are not critical. As you can see at some point the heart will not be able to pump fast enough especially if your goal is to go as fast as possible in a race situation. As your demand for energy and the body temperature rises, your metabolism will also shift from a less aerobic one were energy comes from fatty acids to a more anaerobic one where the energy comes from muscle glycogen. If your session or race is short (up to two hours) you will most likely have enough stored glycogen in your muscles and liver to get you through the effort. However, for longer sessions you will need to restore the glycogen via calories with food. But wait a minute! We just mentioned that food may sit on the stomach for lack of blood to process it since it is getting used for cooling purposes and to maintain the exercise demands. That is correct. I am going to call this the "long distance triathlete dilemma". How to be able to go as fast as possible while cooling the body, providing nutrition that is digestible and maintaining proper hydration. As you can see hydration, nutrition and cooling are all related and one cannot discuss one without taking all the other aspects into consideration. The solution to this is to transfrom your body into an aerobic machine. We at MarkAllenOnline feel this should be the primary training goal. But back to the heat.

If you ask your triathlete friends how they like racing in the heat you will find that some would say "I hate the heat', I never race well on the heat. Other will say exactly the opposite. There are many factors that would determine your ability to perform well in the heat. Certainly some people will have a make up that allows them to be better but many factors can be controlled and you can also improve your ability to race well in the heat via training and by being smart on race day. Here are some of the factors:

Surface area. If you are a larger triathlete you will obviously have more skin and as a result more sweat glands that will cause you to lose a lot more fluids than a smaller person. Also, larger means more overall volume which means your total skin area that enables you to cool yourself will be less than for a smaller triathlete. Attention to your sweat rate is important so that you know how much to drink. Weigh yourself prior and after a workout regularly, count how much you drank and calculate your sweat rate. Remember this will change in the summer.  

Sweat glands. Some people sweat more than others but it is not because they have more sweat glands than others. The surface area is one factor, but also we have to remember that it is the nervous system that activates the glands. A sensitive nervous system can activate more sweating. That is why we sweat during a job interview and why sweat is measured during polygraphs tests. Training in the heat will improve this system.

Gender. Several studies have shown that woman do sweat less then man, regardless of body mass and surface. We of course have observed this on many training sessions.

Body fat. The objective of sweating is to cool the blood, which allows the cooling of the core as cooler blood is transported. If you carry extra fat in your body it will provide resistance to the cooling system. It will act as a blanket preventing heat to be transferred out of the body. Being leaner is a definite plus for better performance in the heat.

Body Mass. Similarly to fat, a muscular individual will provide more resistance to the heat flow that will provide cooling. 

VO2Max. There seems to be a relationship between one's fitness and VO2Max and the ability to dissipate heat. Although VO2Max is something we are born with to a large extent it can be improved. VO2Max is directly related to our weight and our ability to take oxygen during prolonged exercise. Both weight and oxygen play a huge role in dissipating heat, and it is no surprise that if your VO2Max is high you will do better in the heat.

Age. Although at first glance it will seem that older folks are not as good in the heat, it is not directly related to age but rather to their diminished lung and heart capacity and the reduced VO2Max. An older person who stays fit and takes care of their body can still do very well in the heat and much better than younger counterparts that do not.

As you can see there are some factors that when combined together will make one person less apt to perform in the heat. However, with some knowledge of the factors, good training, good body weight and a good head on your shoulders you can perform well in the heat.

If you live and train in a hot environment then your body will adapt and improve on the process of dissipating heat, so your body is well acclimatized. On the other hand, if you live in cold weather and you want to compete in hot and humid climates you will be at somewhat a disadvantage. However, via acclimation, which is the process of training in a artificially controlled environment, you can improve your ability to perform in a hot environment.

Here are four tips that will help you be ready to take on heat race day.

Pick your workout time. Swimming has little to do with heat adaptation because of the controlled environment of a pool. Cycling is better, but with the speed on a bike on the hottest of days there will be a good amount of cooling. The run, however, is excellent for adapting your body to heat.

The best way to do this is to do the bulk of your runs in the middle of the day at the hottest time. Of course, if you live in an extremely hot climate this is not necessary and can actually be dangerous to your health. But if you live in a moderate climate, there are many days with a decent amount of heat near the mid to late afternoon hours.

Training in the hot times will enable your body to make some of the blood protein changes that thins your blood, making you better at dealing with during heat exercise. This is the opposite of what you see most people doing in a hot environment like at the Ironman in Kona. Alii Drive is like a freeway of runners until about 8:00am and by noon it is almost completely devoid of people on their feet. However, to maximize your ability to race in heat, the noon option will serve your body better.

Make a microclimate. If you are gearing for a hot race but just don't live in a location with anything close to what you will encounter the day that counts most, you can still adapt to heat by what you wear in training. A good rule of thumb is to dress one layer more than is really needed to stay warm. So even if it is going to be a 70-degree day, but your race will be in the 90's, you can add a long sleeve shirt over a short sleeve top as a way to make the microclimate right next to your skin closer to what you will need to be used to on race day.

Load up on water and salt. One of the best ways to be ready to handle heat is to start well hydrated before the gun goes off. This process starts long before race day. As was mentioned earlier, weigh yourself before and after workouts. For every pound lost, drink 1.5 pounds of fluids. This will help keep you hydrated on a day-to-day basis.

Then as the race approaches, focus on hydrating during the final 72 hours before your event. Humans can only absorb water a little at a time unlike other animals that can take in huge amounts at one time. Use both water and sport drinks to ensure complete hydration, sipping both frequently in those final three days.

Salt will help you hold onto the water that you do take in as well as become a reserve of sodium in your body to utilize during the race. Add a little extra salt to your foods also during your hydration time. Having a reserve of both (water and sodium) at the start of a hot race will help immensely as the day unfolds.

Expect heat performance. The final thing to keep in mind is that no one goes as fast in a very hot race as they would in a cool race. Expect this and set your mental standards accordingly. Running 30-45 seconds a mile slower in heat can in essence be a better performance than a faster time in cooler climates. Expecting a different feeling will help you to be less worried by your speed in the heat, which ends up reducing the stress that can come if you re judging your race by cool weather standards. And we all know a positive attitude about what is going on can be the trump card that delivers the race of your dreams, even in the heat.

There you go. Train in the heat of the day, create a microclimate to give added heat, hydrate and add a little extra salt in the 72 hours leading up to your race, and above all give your heat speed a positive mental outlook. These four tools will help you maximize your performance in the heat and ensure that you are ready for a great performance at the hot weather triathlons.