The Bodys Response to Heat

The human body maintains an appropriate balance between the metabolic heat that it produces and the environmental heat to which it is exposed. Sweating and the evaporation of the sweat are the body s primary way of trying to maintain an acceptable temperature balance. As sweat (water) evaporates it carries away latent heat, a large amount of heat removed when sweat goes from a liquid phase to a gas phase. However, when heat gain from the environment is more than the body can compensate for by sweating, the result is heat stress. 

Sweating is the body s principal method for removing excess heat. Sweat consists of water and electrolytes (salts). An individual at rest and not under stress, sweats about one liter per day. The sweating rate for an individual under stress of heavy woric or high temperatures is about four liters in four hours. The body must replace water and electrolytes to prevent heat stress or sickness. This is why many people who try to walk out of stranded situations in a desert with only a few liters of water fail and die. They do not realize how profusely they will sweat and how dehydrated they will become. In the pages that follow, we will take a closer look at temperature hazards the process technician may be exposed to in the processing industry. 

Heat stroke is a type of heat stress caused by a rapid rise in the body s core temperature. It is very dangerous and can be fatal. First aid should be rendered immediately. Heat stroke s symptoms are (1) hot, dry, mottled skin, (2) confusion and/or convulsions, and (3) loss of consciousness. In addition to these observable symptoms, the victim will have a rectal temperature of 104.5°F or higher. 

Factors that make a person susceptible to heat stroke include the following  

The last factor can cause heat stroke even in a healthy individual. A person who has one or more of the first four characteristics is even more susceptible to heat stroke. When heat stroke occurs, the body s ability to sweat becomes partially impaired or completely fails. Heat stroke can be fatal because sweating is the primary way the body disposes of excess heat. The inability to sweat causes the body temperature to increase uncontrollably. Action 

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