Our bodies’ organs are designed to perform in a relatively narrow temperature range. Our normal body temperature is 98.6 degrees F (37 degrees C). Typically, our bodies will conserve just enough heat to keep it there. Any extra heat our bodies acquire gets eliminated through a process called thermoregulation. The major actions in thermoregulation are sweating and pushing hot blood out to the skin. Heat can then be lost through the processes of evaporation and convection. However, when this thermoregulation is compromised, it results in the dangerous condition called heat stroke.
Physiology
Heat stroke is a true environmental emergency. An acute heat illness, heat stroke is defined as a condition in which the body’s temperature reaches an excessive height, causing its ability to regulate temperature to fail. This unregulated hyperthermia can lead to cell death, brain, kidney, and liver damage and death if not treated. Although there is no exact body temperature at which heat stroke occurs, typically it happens at temperatures in excess of 105 degrees F (40.6 degrees C).
Causes
In running, heat stroke is usually caused by a combination of prolonged exposure to high environmental temperatures, excessive exertion, improper hydration and poor heat acclimatization. However, it is possible for heat stroke to occur in milder temperatures or during a run of proportionally low exertion levels.
Signs and Symptoms
The classic presentation of heat stroke is the cessation of sweat, dry and hot skin, a very high fever, rapid breathing, rapid pulse and mental confusion or unconsciousness. However, when you are running, your skin may not be dry because your perspiration has not yet evaporated, but it will be hot. Seizures are also possible.
Treatment
Heat stroke requires swift action. First, call 911. The patient requires the immediate treatment of EMS and a hospital. While awaiting EMS, move the patient away from the hot environment into an air-conditioned room, remove his clothing and begin aggressive efforts to cool him. Laying the patient down and covering him with a sheet saturated in cold water works well, especially when combined with a fan. Spraying the victim with cool water or even immersing him in cool water will also work, but take care to avoid causing reflex hypothermia, which will complicate matters. If the patient is alert and able to swallow, give him cool fluids. Ice is a poor method for lowering body temperature and should never be used directly on skin.
Prevention
Staying properly hydrated goes a long way towards avoiding heat-related illness. Drink plenty of fluids before a run, and learn how much and how often you can drink during the run. In races, take advantage of water stations. Slowing down will also ease your body’s efforts to compensate. Avoiding the hot part of the day and running indoors are obvious precautions; however, during a race, you don’t have those options. To prepare for a potentially scorching race, begin acclimatizing well beforehand by setting up workouts that mimic the expected conditions. Finally, wear light, loose clothing.
References
- "Daniels' Running Formula"; Jack Daniels, PhD; 1998
- "Wilderness and Rescue Medicine"; Jeffrey E. Isaac, PA-C, and David E. Johnson, MD; 2008
- "Paramedic Care Principles and Practice: Medical Emergencies"; Bryan E. Bledsoe, DO, et al.; 2009
