The human body is remarkably efficient at regulating temperature during a broad range of conditions. In cold situations it does this by retaining heat, but in hot summertime conditions it must do the opposite and shed unwanted heat and bring core temperature down to the normal 37°C (98.6°F) and the skin temperature to 33°C (91°F).
The two main ways the body dissipates unwanted heat are by a combination of increasing blood flow to the skin and by sweating. Unfortunately, when the humidity level is too high, sweating is not efficient at having the desired effect of cooling by evaporation.
Serina McEntire, PhD, an exercise physiologist well-versed in hot weather running, says, “Core temperature can reach dangerous levels within 10 minutes without adequate dissipation.” The result of this can be several heat-related illnesses. The two most common are heat cramps and heat stroke. Heat stroke can be deadly if not properly treated immediately.
Symptoms and Treatment of Heat-Related Illnesses
Heat cramps manifest as uncomfortable pain, muscle spasms, or both, usually in the diaphragm or the legs due to dehydration and electrolyte imbalance. A runner experiencing this pain should stop running, find a cool spot to rest, and drink a cold electrolyte-fortified sports drink such as Gatorade or Powerade.
Exertional heat stroke, a form of hyperthermia, is much more dangerous and happens when the core body temperature rises above 40.5° (104.9°F). One of the problems with heat stroke, unlike cramps, is that the effects can be mental confusion or disorientation so the victim may not realize his or her condition, and so may not realize the need to stop and seek medical attention. This can especially happen during races or when training for a marathon, when the competitive instinct overwhelms common sense.
The preferred treatment for heat stroke is cooling the body by immersing in an ice bath. If this is not possible, at least seek to apply ice or ice packs under the arm pits and groin area where rapid cooling of the core temperature is more likely. At a minimum, remove excess clothing and spray the victim's body with a garden hose.
How to Avoid Heat Stroke and Cramps
Most prevention measures are simply common sense. For example, hydration combined with a good electrolyte balance is key. This does not mean to simply start drinking right before the run; it should be done during the 24-hour time period preceding the run. Obviously, runners training every day should make it a habit to keep a water bottle close at hand all day.
Ease into it. Don't just jump into a full-fledged running program during the middle of the summer. The process is called acclimation. Start a program (early in the morning or late in the day) with a comfortable number of minutes a day and build up gradually. The bottom line? Have fun, stay fit, but be aware of the dangers and use common sense.
Resources
RunningAcrossTexas.com, "Running in the Heat and Humidity"
MedicineNet.com, "Heat Stroke", p.2
Kelly Smith - Kelly has over 30 years experience as a journeyman carpenter and 20 as a freelance writer and photographer.
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