Runners Should Watch the Weather

NEW YORK (Reuters Health) - People who regularly run should watch the weather and know how to prevent weather-related injury, say sports doctors.

The American College of Sports Medicine (ACSM) now recommends that before heading outside, runners should check the temperature to prevent heat exhaustion, heatstroke, hypothermia (core body temperature below 97 degrees Fahrenheit), and frostbite during running.

The group's newest revised Position Stand, "Heat and Cold Illnesses During Long-Distance Running" appears in the journal Medicine and Science in Sports and Exercise. The statement is meant for medical directors and race officials of distance running events involving elite athletes, and for outdoor events involving recreational joggers. But its recommendations also apply to competitive cyclists, soccer players, and triathletes.

Noting that "the health status of participants varies from day to day," the statement cautions that "compliance with these recommendations will not guarantee protection from environmentally induced illnesses."

The report points out that dehydration is common among participants in prolonged endurance events in both hot and cold weather conditions. It encourages runners to replace fluids lost through sweat by consuming 5 to 10 ounces of fluid every 15 minutes.

It notes that on extremely hot days, on average between 3% and 10% of participants need treatment for heat-related illnesses, such as heat exhaustion (fatigue, sometimes collapse, caused by overexposure to heat), and heatstroke (a life-threatening disorder caused by a breakdown of the body's heat-regulating mechanisms).

To avoid heat exhaustion and heat stroke, the ACSM says runners should be adequately fed; drink fluids before, during, and after exercise; and should get themselves used to running in hot climates by training over several days, gradually increasing exercise intensity in the heat. Runners should not exercise if they have an on-going illness, respiratory infection (cold or flu), diarrhea, vomiting, or fever.

As to hypothermia, recommendations include wearing several layers of light, loose clothing that insulates the skin with trapped air. Areas of the body that lose large amounts of heat3head, neck, legs, and hands—should be covered.

Frostbite occurs when fluids in the skin crystallize after exposure to subfreezing temperatures. It can occur within seconds of exposure, says the report, depending on wind speed, air temperature, and body insulation. The ACSM statement says runners can avoid frostbite and hypothermia in cold windy conditions by dressing adequately and protecting themselves against wet skin and clothing.

"Running is enjoyed by more than 20 million people of all ages and fitness levels. By following the recommendations outlined above, runners can help ensure they cross the finish line, rather than be carried over it," says the ACSM.