Heat is a leading weather-related killer, according to the National Weather Service, and those who spend time outdoors should consider strategies to avoid heat-related illnesses. Extremely hot and humid weather makes it difficult for the body to regulate itself, and those who expect to be outdoors for personal or business activities should take precautions to avoid heat stress. Heat-related illnesses can range from heat cramps to heat exhaustion and heat stroke, which is a serious health emergency.