Surviving the Hotter ‘n Hell

By Jim Argabright

There are a number of American “classics” in cycling that have gained near cult status and become a “must ride” for any amateur cyclist worthy of their salt. One of these classics is the “Hotter ‘n Hell Hundred” century ride held in Wichita Falls, Texas. True to its namesake, the temperatures can be extreme, going well past 100 degrees. To add insult to injury, there can be vicious headwinds along the course that can suck the living life out of you.

With such extreme conditions, why would anybody in their right mind consider riding a century in an event like the Hotter ‘n Hell?

The answer is simple. With some 13,000+ participants, the Hotter ‘n Hell Hundred is not just an event, it’s an experience. The thing is absolutely awesome. With an event this large, there are perks you simply can’t get in a smaller event. You’ll honestly think you’re in the Tour de France. Many of the roads have full closure, all of the intersections are closed to automobile traffic by the police, the course is mostly flat, everyone gets a timing chip that captures your exact start and finish times — not to mention your time at several check points. And if you need it, there are rest stops every 10 miles or so with ice, water, energy drinks, and bars and gels of every description — even pickle juice if you’re so inclined. And with so many people participating, there are enough mini-pelotons to suit anyone’s speed requirements. You can even register (albeit for an additional fee) for a “pace group” that has a premier start position, full motorcycle support, and a team of elite riders driving the pace (i.e. your own personal domestiques!) In short, in spite of the heat, you’ll probably ride the fastest century of your life.

But as I said, all you have to do is survive the heat.

Fortunately, there’s an early morning start (~6:15am) which gives you a reprieve of about an hour and a half before the Texas sun starts to take hold. In this year’s race, the temperature for the first hour and a half held steady at about 80 degrees. But at around 7:45 the temperature began to rise steadily, passing 100 degree mark at around 9:45. At around 10:30, it settled in and held constant at about 106 with a brief high of 108. All that before 11:00am!

So, how do you deal with something like this? Can you survive the Hotter ‘n Hell and live to tell the tale? If you properly prepare yourself and take the necessary precautions during the ride, you’ll sail through the event unscathed, and quite possibly achieve a new PR for the century in spite of the heat.

Be prepared to go the distance

First and foremost, regardless of the heat, you need to be prepared to go the distance. There are no short cuts. A hundred miles is still a hundred miles, even on a relatively flat course with assistance from a peloton. I can’t tell you how many people were suffering by the end of the first hour, and it was only 80 degrees at that point. They simply were not ready to go 100 miles regardless of the temperature. The heat only makes a bad situation worse. Heat will accentuate (i.e. punish) any lack of preparation, training, logistics, or tactics on your part. So, the first step is simple, if you plan to do the Hotter ‘n Hell, and I certainly encourage you to do so, make sure you and your coach have it on your training calendar so that the proper training preparations can be made and you’re fully prepared to go the distance.

Heat acclimation

Numerous studies have shown that repeated low intensity exercise in the heat causes a number of physiological adaptations to occur that allow for better thermal regulation. These adaptations take between 9 to 21 days to occur. Well-trained individuals will need fewer exposures than untrained individuals to fully acclimate. A critical physiological adjustment that occurs over the first three days of acclimation is the expansion of blood plasma volume. However, this change is temporary and blood volume usually returns to original levels within 10 days. This early expansion of blood volume however is important because it supports stroke volume and allows the body to maintain cardiac output while other important physiological adaptations are made. Other adaptations include an earlier onset of sweat production and (of course) a significant increase in the rate of sweat production. In addition, the sweat that is produced becomes less salty with acclimation, thus conserving sodium. The amount of sweat produced often increases on the most exposed body areas such as the arms and legs, the areas that are most effective at dissipating heat.

Achieving heat acclimation

Heat acclimation involves more than just resting in a hot environment (although this helps). The benefits and rate of acclimation depend upon: 1) the environmental conditions (i.e. temperature and humidity) during each exercise session 2) the duration of the exercise-heat exposure and 3) the rate of internal heat production (i.e. exercise intensity).

In short, an athlete must exercise in a hot environment at the proper intensity to attain acclimation that carries over to exercise in the heat. Simply sitting in hot environment, such as a sauna, for long periods each day will not fully or adequately prepare the individual for physical exertion in the heat, at least not to the same extent as will be accomplished by exercising in the heat. So, take note.

For those athletes that live in hot environments and who have become proficient at avoiding the heat by riding indoors with air conditioning and fans, early in the morning, or at night will need to schedule riding sessions outside during the warmer parts of the day in the three weeks prior to the event. For those of you that live in cooler climates you will need to find a way to simulate the higher temperatures you expect to encounter. For example, you can ride indoors on your trainers with the heat turned up, with the fan turned off, or with additional clothing on to simulate a hot climate.

Training in the heat for the Hotter ‘n Hell in the days prior to the event also allows you to test equipment configurations, clothing, brand of sun screen, number and placement of bottles, rate of fluid intake, etc. that will constitute a successful ride.

Sources of heat during the Hotter ‘n Hell: metabolic, conduction, convection, and radiation

For any event like the Hotter ‘n Hell that occurs in high temperatures, there are a number of avenues of heat transfer that will transmit heat energy to your body. There are four fundamental avenues of heat transfer that we’ll discuss: metabolic heat generation, conduction, convection, and radiation. Thoroughly understanding these processes will be of infinite value to you in minimizing their occurrence.

Metabolic heat generation

When you exercise, only a small part (usually less than 25%) of the energy expended goes to muscle contractions, the rest is converted to heat. Simply put, the higher your exercise intensity, the more metabolic (internal) heat you generate. The more metabolic heat you generate, the more heat your body needs to dissipate in order to maintain its core temperature at reasonable levels. So, in something like the Hotter ‘n Hell, you can help regulate your core temperatures by simply reducing your intensity at the appropriate times and by limiting sustained hard efforts. In that vein, it goes without saying, the easiest method for reducing intensity while maintaining speed in any road race is riding in the peloton and minimizing effort. The only difference with racing in the heat, though, is you need to be far, far more cautious about how you conserve energy and when or where you attempt a break or how long you pull at the front. In temperatures in excess of 100 degrees, the rule of thumb for breaks and pulls is “don’t.” For those of you just looking to complete the Hotter ‘n Hell century and perhaps looking to nab a PR, just finding a peloton (or signing up with a pace group) with a comfortable speed will get the job done. Stay in the pack and don’t take any turns at the front. If your core temperature is within proper limits and you’re feeling good and have energy to spare, simply hook up with a faster peloton when one goes by. As I mentioned earlier, there are lots of advantages of a large event like the Hotter ‘n Hell, one of those advantages is there are lots and lots of mini-pelotons to choose from. Use them to your advantage to maintain speed while keeping your intensity within reasonable limits and thus minimizing the amount of metabolic heat your body generates.

Metabolic heat won’t be the only source of heat your body has to deal with. There are other forms of heat transfer that are important to understand — and as I mentioned above understanding them thoroughly will allow you to deal with them appropriately.

Other sources of heat transfer (to you, the rider) include conduction, convection, and radiation. We’ll discuss each separately. However, the most critical thing to remember about heat transfer in general is that heat energy flows from hot to cold — and never in the opposite direction. In other words, the temperature of your surroundings versus your skin temperature will dictate in which direction heat energy will flow. If your surroundings are cooler than your skin temperature, heat energy will flow out of your body. On the other hand, if your surroundings are hotter than your skin temperature, heat energy will flow into your body. That’s the essential point to keep in mind. We’ll talk about this in more detail as we discuss the various forms of heat transfer and their effect upon you, but just understanding that one point is a powerful tool that will allow you to properly appraise the effects of most environmental conditions.

Conduction

The first form of heat transfer we’ll talk about is conduction. Conduction involves the transfer of heat from one solid material to another when the two are in contact. In cycling this is usually limited to where you make contact with your bike: the seat, the pedals, and the handlebars. Since these items are well insulated, their contribution to heat transfer, either to or from your body, is minimal, if there’s any at all. So, no need for concern there. In the Hotter ‘n Hell, one possible use of conduction to work in your favor to help keep you cool can be in the form of a Camelback (I’m using “Camelback” here in the generic sense) filled with ice and water. The Camelback pressed up against your back will allow for heat transfer from your body to the Camelback. Although the wearing of a Camelback is not too common in road racing, the people who manufacture these things do manufacture some very minimalistic models that lend themselves to a ride like the Hotter ‘n Hell. So, it’s certainly something to consider.

Convection

The second form of heat transfer, convection, is more interesting. Convection involves heat transfer via a liquid or gas flowing over a body. For example, cool air flowing over your skin will have a cooling effect as energy is transferred from your warm skin to the cooler air — this occurs even when there is no evaporation. Simply having cool air flowing over your warm dry skin will have a cooling effect as energy transfers from an area of high temperature (your skin) to low temperature (the air). The greater the difference between the air temperature and your skin, the greater the transfer of energy. In addition, the faster the air is moving over your skin, the greater the cooling effect will be as well (more air flow equals more energy transfer.) However, and this is extremely important, the direction of energy flow changes when the air temperature exceeds your skin temperature. As I mentioned above, heat energy will flow from an area of high temperature to low. When the air temperature is higher than the temperature of your skin or clothing, heat energy will flow from the air to your skin and clothing. Instead of a cooling effect, the air will have a warming effect as it transfers energy to your body. When exercising, skin temperature will range roughly from 80 to 100 degrees depending on how much blood is being routed to the skin surface and the temperature of the blood itself, but, whatever the case, when the surrounding air temperature exceeds 100 degrees, the conditions exist for the air to have a warming effect on your skin and thus transfer heat energy to your body. If you’ve ever had the opportunity to use a convection oven (common in commercial kitchens), you will know just how quickly things can cook by way of convection!

So, how do you minimize the effects of convection in extreme temperatures? Evaporation, which we’ll discuss further below, will be your biggest ally. However, you can use convection to cool yourself as well. The act of pouring cool water from an external source (say, your water bottle) over your skin will use convection to your favor as heat energy will flow from your warm skin to the cool water. The additional water will also aid heat loss due to evaporation. So, there are several benefits for dousing yourself with water. In situations of high humidity where heat loss due to evaporation is severely restricted, dousing yourself with cool water from an external source will be one on the few ways you’ll have for keeping yourself cool. In such situations, take advantage of external sources of cool or ice water from teammates, support vehicles, feed zones, or from rest stops.

Radiation

The third form of heat transfer is radiation. Radiation is the transfer of heat energy via electromagnetic waves. What’s unique about radiation is that no direct physical contact is necessary to transfer heat between two objects. Radiation does, however, require a “direct line of sight”, i.e. nothing between you and the energy source. A good example of radiation is the warmth you feel on your skin or clothing when you’re exposed to direct sunlight. If there is cloud cover or trees blocking the sun from reaching you, heat transfer from radiation from the sun will be dramatically reduced or eliminated.

Again, radiation follows the same general rule as conduction and convection: energy will transfer from a point of high temperature to low. In the case of the sun, given that the temperature of the surface of the sun is higher than your exposed skin and clothing, there will be a warming effect as heat energy is transfer from the sun to you via radiation. Alas, the sun is not the only source of radiant energy — any object, let me repeat that, any object or objects in your surroundings that are hotter than your exposed skin temperature or your clothing will transfer radiant heat energy to you and thus have a warming effect. This includes pavement, houses, signs, walls, anything in your surroundings that has a temperature higher than your exposed skin or clothing will radiate heat energy to your body. So, as they say, you get it from all directions.

Another aspect of radiant energy, given that it’s being carried by electromagnetic waves, is that it exhibits wave behavior. In short, radiant energy can be reflected. Now this is both good and bad news. The purpose of wearing light colored clothing in extreme heat is that light colored clothing reflects a significant portion of the electromagnetic spectrum such that less radiant energy is transferred to you. Light colored clothing is one of your best defenses against radiation. That’s the good news. The bad news is that radiant energy from the sun and other sources can be reflected off of other objects (i.e. pavement or walls). For example, hot pavement not only radiates energy to you because of its temperature, it also reflects radiant energy coming from the sun back to you. So, there’s a double whammy going on there.

Methods of reducing heat transfer to your body from radiation under hot conditions revolve around blocking or reflecting the sources of radiation. As mentioned above, light colored clothing will reflect a significant portion of radiant energy. Riding in the peloton with riders on all sides of you will also be beneficial as the riders around you will be the ones picking up the radiant energy (or reflected radiant energy) from your surroundings.

In summary, sources of heat energy come from a multitude of sources: metabolic heat, conduction, convection, and radiation. Be aware of them and always be thinking on how to minimize their effects. We’ll now switch gears and focus on the primary methods on cooling ourselves under extreme conditions and how we can aid our bodies on maintaining our core temperature within reasonable levels.

Primary sources of cooling during the Hotter ‘n Hell: Evaporation and Ingestion

If things sound pretty dismal at this point, take heart. There are some exceedingly powerful mechanisms for cooling yourself in the heat that we’re about to discuss: Evaporation and Ingestion.

Evaporation

Evaporation of moisture from the skin is the primary avenue for heat dissipation during exercise. Whether the “moisture” is sweat or water (from, say, your water bottle) doesn’t really matter. The evaporation of moisture from your skin has an astounding cooling effect — the transformation of liquid to vapor absorbs tremendously large amounts of heat energy. The evaporation of 1 liter of sweat (or water) in an hour results in the dissipation of 680 watts (2,428 kilo joules per hour) of heat energy. That’s a lot. Be aware that sweat or water that drips off the skin or remains on the skin or clothing does not contribute anything to heat loss associated with evaporation. This get exasperated in situations in which there is high humidity in which little to no evaporation is occurring and the moisture just sits on your skin or clothing. As such, in situations of high humidity, you have very little or no heat loss occurring due to evaporation. Fortunately, for the Hotter ‘n Hell, the humidity is usually within reasonable levels and evaporation represents a significant avenue of heat loss. As I mentioned, it doesn’t matter where the moisture on your skin comes from for the evaporation to be effective. It can be sweat, or it can be water from an external source. It doesn’t matter. It should also be mentioned that cold water (and by cold water I mean water that is cooler than your skin temperature) will have the added benefit of cooling by convection (as described above, heat loss due to convection occurs whenever a fluid flowing over the skin surface has a lower temperature than your skin). Alas, cold water will have a cooling effect due to convection even when there is absolutely no evaporation occurring at all! So, even in situations of high humidity, dousing yourself with cool water is highly effective.

Of course, your supply of moisture, be it from sweat or water, is limited and must be replenished. And that leads us to our next topic, ingestion.

Ingestion

Last, but not least, we have what I call “ingestion”. Certainly, we’re all aware that any sweat that your body expels to cool itself needs to be replenished. Ingestion is simply the consumption of fluids to replace that lost by sweat. All of the usual recommendations for replacing fluid apply here. Consuming approximately 8 ounces of fluid every 15 minutes will be required. However, I emphasize the word “approximate” here. The exact amount of fluid intake for a given individual will vary based on the rate of sweat production, gastric emptying, and a number other factors. This is one area where a little experimentation goes a long way. Doing practice rides in the heat as you acclimate will allow you to experiment with different brands and flavors of sport drinks, their dilution, the amount of water versus the amount of sport drink you carry, and the amount of intake you can handle, etc. Dialing in all of these factors will be an important part of your preparation for your event.

Another vitally important part of ingestion is fluid temperature. Not only does fluid intake replace that loss by sweating, but it also has a cooling effect due to its temperature. Any fluid cooler than your core body temperature will assist you in cooling your body. It takes energy to raise the temperature of any fluid. The cooler the fluid the better. An ice, fluid combination is best, something on the consistency of a “Slurpee” is ideal and will allow the greatest cooling effect while replacing lost fluid at the same time. Again, a bit of experimentation is required (i.e. essential) here to see what your body can tolerate. Logistics will play a role as well in determining how you might receive such drinks in the event you’re participating in.

Summary

We’ve covered a number of topics with respect to heat transfer and their effect upon you, the rider. Use the knowledge gained here to your advantage. Since it’s impossible to cover every aspect of how to ride and survive in the heat in a single article, I encourage you to continue to expand your knowledge. A good of discussion on the subject can be found in any good human physiology text that focuses on sport science. My favorite is “Physiology of Sport and Exercise” by Jack Wilmore, et. al. It devotes an entire chapter to the physiological effects of heat and heat transfer and is well worth the read. Ideally, I hope I have encouraged you to consider giving the Hotter ‘n Hell a go and work with your coach in preparing to do participate in the event next year.