One of the best things about living in Texas is the endless days of summer. However, heat related illness affects thousands of central Texans every year. We are not immune. Imagine it is the middle of August and you get a SWAT call out at ten in the morning. It is already ninety degrees outside. As the team deploys around the target you notice that even though there may be some cover or concealment from the suspect, there is likely no cover from the sun. No shade. After about three hours in the sun standing behind your armored vehicle you find that you are getting impatient and have headache. Your teammates mention that you are being irritable. More irritable than normal perhaps. The team is already spread thin and now because you are not the only one experiencing these symptoms its about to get thinner. Your only hope is to understand what is happening and do some about it.

The human body has its own internal furnace called metabolism, which along with energy, produces heat. Heat can be transferred both to and from the human body depending on the environment.

Radiation

direct transmission of heat to the surroundings, accounts for roughly 65% of heat transfer when the surroundings are cooler than current body temperature.

Convection

occurs when body heat from metabolism heats water molecules in the air that surround the body. This method of heat transfer is used by the body for only about 10-15% of heat regulation.

Conduction

the exchange of heat from direct contact of the human body and another surface. This can be a very reliable source of heat loss if the contacted object is cooler than the body.

Evaporation

the process of changing liquid to gas. This process uses a great deal of energy and that energy use results in heat loss. Evaporation can only result in heat loss and cannot contribute to an increase in body temperature. Sweating is a function of evaporation and is used frequently by the human body to regulate heat production.

Heat related illness typically manifests in two very distinct fashions. Both are very serious and individuals experiencing any signs or symptoms of a heat illness should seek medical attention from your tactical medics or other EMS resource.

Heat Exhaustion

A condition with symptoms including severe sweating, dizziness, light-headedness, fatigue, nausea, vomiting, headache, fast heart rates and rapid breathing. Individuals will typically feel hot to the touch and may have temperature as high as 140 degrees.

Heat Stroke

The most severe form of heat related illness and will present with a triad of symptoms including temperature greater that 105 degrees, alteration in the individual’s level of awareness and a cessation of sweating. This condition is a true medical emergency and needs immediate treatment.

The best defense is a good offense so the first step is to avoid dehydration. Signs of dehydration include increased thirst, dry mouth and mucous membranes, decreased urine output, increased heart rate and weakness. Urine output should be constant and urine should be light yellow to clear when well hydrated. Hydration doesn’t just happen. In order for your body to perform to its potential you must stay hydrated.

Individual solutions begin with proper planning. Adding some sort of personal hydration system to your deployment gear is a necessity. Find a hydration system that holds at least 2 Liters of liquid so that you have enough to last a few hours. It’s best not rely exclusively on sports and energy drinks to keep you hydrated because it is possible that their inherent high sugar content may promote dehydration. Fluids of this nature should be diluted to a 50/50 mixture with water. You would have to consume something like half a gallon an hour of the best the sport drinks to take in 1 gram of sodium. The best solution would be to drink water and rely on food to replenish sodium.

Hyponatremia or low sodium can cause cramps and other performance limiting effects. Sodium loss occurs at different rates in each person, and is also workload and temperature dependent. Therefore it is difficult to predict how much you will lose in any given situation. As an example, an Iron Man triathlete loses about 1 gram of sodium an hour. I would suggest taking in at least .5 grams an hour when temperatures are extreme. A great source for this replenishment would be a small bag of salted pretzels such as Rold Gold. The best foods to eat are high in sodium (salty foods also promote thirst) and carbohydrates.

Individuals can also take some steps to help stay cooler overall. Wear layered clothing that can be removed as it heats up and moisture wicking garments next to the skin. Have sun block readily available like your mother used to tell you. Create heat escape routes by removing your balaclava, opening cuffs, untucking your blouse, unblousing pants and unbuttoning your trouser fly. Try to get some airflow under your vest and between your head and hat/helmet to help with evaporative cooling. Finally, find shaded areas and take frequent breaks to rest and rehydrate to decrease body temperature.

It is imperative for the team to have adequate volumes of fluids and food for operators above and beyond what is carried by the individual. Stocking fluids in the armored vehicle or having someone from the command post making a run to the corner store during callouts should be standard practice. Having large volumes of intravenous fluids available for medics to mainline team members who can then return to the operation is also important. Another option is to keep cases of chemical ice packs readily available. They are shelf-stable and provide about fifteen minutes of cooling. They are great to put under armpits or in any other area that arteries come close to the skin’s surface such as wrists or groin area and help promote conductive cooling. Another great solution is the use of air-conditioned city buses, which provide a secure location for team members to get out of the sun and rehydrate.

Tactical aspects of an operation are usually planned meticulously, but in some cases environmental factors will take a larger toll on individual operators than suspects will. Preplanning how to respond to extreme environment factors will help to take one more element of chance out of the operation. Just about every team has limited manpower to handle an incident, and we must all make the most of what we have. Don’t let the loss of team members to extreme heat have a negative effect on the mission. Plan ahead. The heat in Texas is predictable, therefore its effects are largely preventable.

About the Author Patrick Phillips is a licensed paramedic and tactical medic with the Austin SWAT Team. He has been with Austin/Travis County E.M.S. for 9 years.