Whenever you’re running in the heat such as competing in the Hawaii Ironman, you need to be smart to optimize your chances of success. Heat is always a major challenge and forces you to adopt a slower pace than when it’s cooler out. So whether you’re training for a 5K or a bucket list marathon, read on.

It’s important to know how your body will react to extremely hot weather and blistering heat. With the proper preparation, you can learn how to get used to running in the heat. You’ll be able to run hard while others are reduced to walking. I find that being prepared for the heat is most important when running a marathon such as the Boston Marathon or events such as an Ironman triathlon.

First, we’ll learn about heat acclimatization and thermoregulation. Then we’ll go over a few tips to allow our bodies the ability to adapt to hot weather appropriately.

What is Heat Acclimatization?

There are benefits to running in the heat. Your body will become stronger due to the increased pressure put on it. However, you can’t just go and run in hot conditions and expect everything to be great.

Running fast in the heat requires heat acclimation, which is a process of slowly exposing your body to hotter temperatures over the course of two to three weeks (according to some experts). Personally, I feel that it takes much longer for your body to adapt efficiently and to develop the mental confidence required to race in really hot environments.

Humidity versus Dry heat

Hawaii has humidity. Arizona has dry heat. Cooling the body includes the evaporation of sweat on your skin. In a humid environment, you won’t have the benefit of cooling down via sweating. Thermoregulation will be more difficult. Also, sweat is warm, so you’ll be covered in warm fluids when you want to cool down.

In dry heat, your sweat evaporates very quickly and it can be difficult to realize how much fluid you’ve lost.

Heat Exhaustion

Heat exhaustion is a condition that can occur when you are exposed to high temperatures and your body is unable to cool itself down. Symptoms of heat exhaustion include:

• feeling faint or dizzy
• nausea or vomiting
• headache
• increased heart rate
• increased sweating

If you think you or someone else may be suffering from heat exhaustion, it is important to seek medical help immediately. Heat exhaustion can lead to more serious conditions such as heat stroke, which can be life-threatening.

Heat Stroke

This is a condition caused by your body overheating, usually as a result of prolonged exposure to high temperatures or physical exertion in hot weather and humid conditions. This can lead to a range of symptoms, including:

• confusion
• loss of consciousness
• seizures.

If not caught quickly, heat stroke can be fatal.

There are two types of heat stroke – classical and exertional. Classical heat stroke usually affects the elderly or very young, and those with chronic medical conditions. Exertional heat stroke usually affects healthy adults who are involved in strenuous physical activity in hot weather.

Heat stroke can be prevented by staying cool and hydrated to minimize fluid loss in hot weather. If you must exercise in hot weather, do it during the cooler parts of the day to acclimate slowly over time. Make sure you always drink plenty of fluids such as a sports drink.

Heat stroke is a medical emergency and should be treated as soon as possible. Seek emergency medical treatment immediately if you or someone you know appears to be suffering from heat stroke.

After heat acclimation, you will be better able to tolerate running in hot weather. However, there are still some things you can do to stay cool during runs. We’ve compiled a few tips below.

Thermoregulation – Cliff Notes Version

Our body has a built-in way of trying to prevent heat exhaustion and heat stroke. When we sweat in response to hot conditions, that is referred to as thermoregulation.

Thermoregulation is the ability of the human body to maintain its internal temperature (core temperature) within a relatively narrow range. This is accomplished by a variety of mechanisms, including sweating, vasodilation, and panting. Basically, it’s what keeps us alive since too much heat can be lethal. Keeping our body cool is good.

The thermoregulatory center is located in the hypothalamus, and it consists of two regions: the preoptic region and the anterior hypothalamic region. The preoptic region is responsible for regulating body temperature in response to changes in environmental temperature, and the anterior hypothalamic region is responsible for regulating body temperature in response to changes in internal heat production.

The thermoregulatory center is sensitive to changes in the body’s temperature, and it responds by adjusting the level of activity of the various thermoregulatory mechanisms. Sweating is the most important thermoregulatory mechanism in humans, and it is controlled by the sympathetic nervous system. Vasodilation and panting are less important thermoregulatory mechanisms, and they are controlled by the parasympathetic nervous system.

The core temperature is the temperature of the internal organs, and it is maintained at a constant level by the thermoregulatory center.

What does all this mean? It says that your brain knows when to react to hot environments and cool itself down. The good news is that we can adapt and with the help of our brains, we can survive and be successful in hot weather.

When Can Make The Heat Feel Worse Than It Really Is?

Before we begin going over a plan to deal with the heat, it’s helpful to know that some factors that we control can make the heat feel worse than it really is. It’s important to avoid these like the plague if you want to do well.

Coming From Cooler Temperatures to a Hot Environment

This is always a dangerous situation. It is not uncommon for athletes or runners who live in cooler temperatures to travel to locations with hot weather to compete in races. This can present a problem if the body is not acclimated to the heat of the race environment and it may have difficulty regulating its temperature.

You can be training in 80-degree heat for six months, but if the race is in 90-degree heat, your body won’t be ready for it. It will wear you down, which is why the Kona Ironman always surprises people. The weather says 85 degrees, but the radiant heat from all the surrounding lava rock puts the real temperature well over 100 degrees. That heat index and humidity are a dangerous combination and they overwhelm even the fittest athletes.

I’d compare this to taking an ice bath at home and then immediately running in 90-degree heat. The shock will be amplified for your body.

Lack of Sleep

A University of Washington study has shown that sleep deprivation alters (hurts) thermoregulatory responses. The results showed that (in both hot and cold temperatures) the body began to lose its ability to accurately control its core temperature after a single night of sleep deprivation.

In other words, if you’re tired, heat will feel hotter than it should. Your body’s own cooling mechanisms may be sluggish in their responses. Remember that you probably won’t get a lot of sleep the night before the race, so if your body isn’t overly rested before that, it will be evident during the race.

Note – it’s harder to sleep comfortably and soundly if you have an injury. So make sure you have the best running shoes and the best running insoles for your body so you stay healthy.

Too Much Caffeine

I personally have found this out the hard way. I got into the habit of drinking too much caffeine leading up to Ironman Florida one year. I thought I had prepared well, but work had been stressful and my caffeine intake had become higher than normal so I could function with less sleep.

Over a few months, my normal routine was to rely on coffee instead of proper sleep. I was not truly well-rested on race day, and my body let me know. It was hot, and I was toast.

Going through this forced me to dial back the caffeine and to begin to pay closer attention to the total hours slept and the quality of my sleep, rather than how I felt after my morning coffee.

Dehydration

This one is simple. If you’re dehydrated, your body is already compromised and won’t be able to do any of its normal functions (such as thermoregulation) well. <