With the hot summer months looming up on us, it’s time to review the single most serious threat to the outdoor competitors’ life--heat. It has a higher fatality rate than sudden death (heart attacks), or being killed by automobiles while running.

Elite triathletes and runners have even been known to have heat problems, but it’s the semi-conditioned rank and file competitior who is most susceptible to heat injury. Even dehydration can lead to unconsciousness and death if allowed to escalate into heat exhaustion or heat stroke.

Let’s examine the factors that combine to cause heat problems: air temperature, air movement, humidity, exposure to the sun, acclimatization and the intensity or duration of your exercise session or competition.

We can generally tolerate temperatures as high as 80-90 degrees F. because we’re able to sweat as much as two liters per hour. Given dry air, most of this sweat evaporates, cooling the body as it does so. However, as humidity increases the already saturated air absorbs less sweat, and body heat begins to build up.

The greater the air movement around us, the greater the cooling effect as air currents enhance evaporation. A headwind helps evaporation but a tailwind actually reduces the airflow over the body, hindering evaporation.