University of Virginia Health System

KNOWING WHEN TO STOP IS KEY TO PREVENT HEAT STROKE

Keeping cool can save your life. Environmental factors, such as heat, humidity and direct sunlight put a significant tax on the body's ability to dissipate heat and utilize the body's fluid status causing heat exhaustion and heat stroke. Heat-related illnesses can be serious and even deadly but also can be prevented by recognizing early signs such as dizziness, fatigue or muscle cramps. But for some athletes who push themselves to the limit, knowing when to stop may be difficult.

It can be tough to manage this problem in athletes because they have the attitude to continue and work through any discomfort that they may have, said John MacKnight, associate professor of Clinical Medicine at the University of Virginia Health System. So it is vital to educate athletes on the warning signs of heatstroke: excessive fatigue, shortness of breath, vomiting and confusion. In a hot environment, these are not normal responses and they need to give their body a rest.

A person suffers heat stroke when they lose the ability to dissipate heat and the core body temperature rises to a dangerously high level that ultimately causes cellular and organ dysfunction. According to MacKnight, the hallmarks of the condition are a core body temperature over 104 degrees, absence of sweating and central nervous system dysfunction.

The difficulty with heatstroke in an exertional setting is that you hope that the patient, before he gets to that point, will recognize that they've stopped sweating, that they feel weak and that they are getting nauseated. But because it affects the central nervous system, the person might lose the ability to know there is something wrong.

MacKnight advises that if a person experiences these symptoms, discontinue activity immediately, seek cool surroundings or shade and try to lower body temperature by applying ice to the neck, armpit or groin area. If someone has collapsed from signs of heat stroke, call 911, move the person to a cooler place and try and lower body temperature.

To help prevent heat exhaustion or heat stroke MacKnight recommends:

• Avoid activity in intense heat of the day usually between 12-4 p.m. Try to do your activity in the early morning or evening when the temperature may be lower. Even outside of those times, pay attention to the humidity because humid conditions make it more difficult for the body to utilize its fluids. If you have to be outside, seek shade.
  
  
• Pay close attention to fluid intake. During hotter portions of the summer, drink eight ounces of water every hour and every 15 minutes if outside in the heat.
  
  
• Wear lightweight, light-colored clothing that allows air to get to the skin and take the heat away from the skin.

August 3, 2001