This Hack came on the coldest night of my life. It was my first World’s Toughest Mudder (WTM) in 2012. I had no idea what I was getting into except for the little information that former Navy SEAL, Stew Smith, and ultra runner, Jared Busen, could provide on how to prepare for a 24 hour event that would be in and out of water. Even the local dive professionals were like “you want to do what while wearing a wetsuit?”

I faced the most difficult experience of my life when the temperatures dipped below freezing. Ice was formed on obstacles. It was during these eight hours that I started burpees in order to prevent hypothermia. Chicken soup was no longer for drinking but instead warmed the coldest parts of my body. I remember thinking to myself around this time, “we should not have to deal with this. I have to be better prepared next year!”

I hope none of new class of WTM rookies will never know what temporary peripheral neuropathy is nor be subjected to the horrors of seeing a warming tent full of hypothermic mudders. At WTM you either come prepared or Mother Nature will win. It can even take down the Toughest Mudders! This article is long but I can assure you, very necessary!


Photo Credit: Bio911

Science of Thermoregulation

The human body is a heat generating machine. As we evolved and became more intelligent we lost what evolution provided other animals; the ability to hold in body heat. This made us much more adaptable to various climates; however, it can be a detriment to us when doing something like WTM. The human body cools itself in three ways. These cooling effects can happen individually or all at the same time depending on the environment. Those ways are the following:

  • Radiation– the transfer of heat being emitted by one body and then absorbed by another (placing ice on an injury)
  • Convection– the transfer of heat through the circulation of air (sitting in front of a fan to cool down)
  • Evaporation– reduction in temperature resulting from the evaporation of sweat, which removes latent heat from the surface of the skin.


The question is how does this effect the body in a situation like World’s Toughest Mudder.


Sweating is probably the most efficient method of heat loss from the human body. The evaporation of that sweat helps remove heat that is right next to the skin. This air next to the skin is warm due to the body radiating heat and warming it up. Keeping this warm air near the skin moving is the key to our loss of heat. This is the purpose of Under Armour type fabric. This clothing wicks away the moisture (speeding evaporation), allows air transfer to recycle the radiating warm air, and accomplishing this with a fabric that won’t absorb the moisture, allowing it to dry quickly.

The “Cold Gear” Under Armour fabric adds that fuzzy underneath layer to create a space between the compression shirt and your skin. This space allows some of the radiated warm air to be held next to the skin to help insulate you from the colder air outside. This works great unless the fabric is soaked. Convection cooling comes in when the air is moving which further helps speed the other two processes. Every runner is keenly aware the “cooking” effect that happens on a warm day with no breeze when you have to stop at a stoplight and you start to overheat.  Fortunately or unfortunately for us, the desert is always breezy because of the constant turnover of surface warm air and cooler atmospheric air. Sometimes there is too much wind as in the 2014 sandstorm.

Why is all of this such a big deal when it comes to the WTM?

13284979_race_0.3113175596848219.displayThe combination of warm day/ cold night and the fact athletes are constantly in and out of the water for 24-hours means you basically have to have gear for everything! Early in the race, you will be moving relatively quickly and generating a decent amount of heat. However, as you fatigue, you naturally slow down to a trot or even hiking. This coincides with the arrival of night ops when the temperature in the desert plummets.

Now your standard race clothing cannot keep you warm. This is where the wetsuits comes in. The problem is those suits weren’t designed to run in. Bear in mind that during the evening the temperatures are still mild. This is when you will want options. Maybe a short wetsuit or a thinner one until it gets colder. Overheating is a real problem in a wetsuit when you are not actually in the water. The wetsuit is designed to create a temperature stable environment while you are in the water. Your insulated clothing attempts to do this out of the water. I’m going to break down these differences so you can better understand.



  • Light summer clothing allows you to shed body heat as best possible. It’s usually lighter in color so it absorbs less light heat from the sun.
    • More insulated winter clothing is designed to hold your body heat in and provide an air barrier to the colder air outside. Layering assists this by helping trap more air inside your clothes and therefore creating a larger air barrier.
    • The problem with nearly all clothing is it flattens when it gets wet and it loses its ability to trap air. On top of that, the wet clothing now sucks heat from the skin because of water’s ability to absorb heat. Now your wet clothing can actually make you colder whereas bare skin would allow the water to quickly evaporate. Not to mention the fact that the soaked clothing is now adding weight this is not good when you have to climb obstacles.Designed to provide a temperature stable environment on land.


  • IMG_207048998410781Designed to provide a stable temperature environment while in the water.
    • The wetsuit traps a small amount of water inside the suit which is then warmed by the body through radiation. This provides a much more efficient barrier against the cold water you are swimming in because water is such a good insulator of heat. The MM rubber thickness adds another level of insulation. The idea is that your body will continue to warm the water inside the suit faster than the cold water in which you are submerged can draw that heat out of the suit. The longer you are in the water or the colder water the more important the MM thickness of the suit. Also, make sure that your suit fits correctly. If it does not then you will have too much water transfer and you will get cold.
    • The key thing to remember about wetsuits is body heat transfer out of the suit occurs in only one way. This is through radiation. The suit will not allow air to pass through it nor perspiration to exit as a fabric like Gore-Tex will. This means that the heat must be transferred to the suit and then radiated to the outside environment.
    • Outside of the water your suit will shed most of that insulating water quickly. This leaves only a thin layer of cold, wet rubber between you and the cold air. This can cause a quick drop in body temperature if you aren’t moving fast enough.
    • We also lose a lot of heat through our heads so make sure to have a neoprene hood on at all times during the night. If you get hot, then switch to a swim cap.
    • Since radiation is the only option for heat transfer you have to be smart and understand how to use this knowledge. Basically, because most suits are black, the sun will warm it quickly during the day, so be careful not to overheat. You can quickly “cook” in the suit, so unzip it if necessary or flood the suit when you hit the water. At night, keep the outside air off the suit. Wear a windbreaker to accomplish this. This is a must during high winds!

The basic information needs to be provided so that everyone can develop their plan. The following points are what I believe is necessary for putting together a viable plan for WTM.


These are My Keys Points for Success.

  • Daytime 1:
    • The sun and terrain will heat you up!
    • Wet clothing will cool you down
    • Sunscreen block out UV rays but also traps in heat
    • There is no shade on this course


  • IMG_7221978787211Evening:
    • At dusk, the temperature will drop over the course of about one lap so be prepared for this transition. Hyperthermia can happen fast and will shut down your performance. Hypothermia at WTM takes a little longer and long as you are prepared, and you keep moving.
    • It’s good to have the option of a short wetsuit or suits of varying thickness. Make sure you bring EVERYTHING you have. Don’t leave the extra wetsuit in the hotel because you think you don’t need it.
    • Make sure you keep yourself warm throughout to preserve grip strength. This includes your hands. Good gloves are key
    • You will need wool or neoprene socks to keep your feet warm.
    • Make sure you have a windbreaker jacket. I also recommend windbreaker pants just in case. You MUST keep the wind off your suit and they won’t add much weight.
    • Make sure you have a neoprene hood and a cap. You must keep your head warm. A mask and goggles are also good in high winds.


  • Daytime 2:
    • Transition slowly back to regular clothing. Accomplish this with your short or thinner wetsuit. Your fatigue and hydration levels affect your thermoregulation. It’s much easier to get cold in this state. Also, the desert takes a bit to warm up.
    • Have a second set of regular race clothes for day two. The last thing you want to do it put on cold wet clothes from the day before. The fact you must be out on the course after 1pm will make this change necessary because it will be warm again at the end of the race.


  • Other points
    • 2014 weather recap: High- 72⁰F (22⁰C)/ Low- 43⁰F (6⁰C). Wind gusts to 34mph
    • 2015 Forecast (as of 11/3/15): High- 69⁰(21⁰C/ Low- 49⁰F (9⁰C). Wind gusts to 17mph
      • Basically, if you were there in 2014 then plan for more of the same. If not, then bring all of the gear you have and use what you need.
    • Ingesting warm liquids can warm you quickly from the inside so take advantage of the Outpost tent
    • The opposite is also true. Cold liquids will help cool you in the event you overheat.

The main key to conquering the World’s Toughest Mudder is coming prepared and never underestimating Mother Nature.