Navy personnel who are required to work in hot, humid spaces must be aware of heat stress. To ensure this awareness, the Navy has established a strict program to prevent incidents of heat stress. This program requires that any circumstances that result in a case of heat exhaustion or heatstroke be reported to higher authority.

When personnel are required to work in hot spaces with stagnant, moisture-laden air, the environmental conditions (temperature, humidity, and airflow) are such that the heat load in the human body builds up. As the bodys internal temperature rises and the rate of heat buildup cannot be balanced by the evaporation of perspiration, the human body becomes stressed. A person who continues to work in this environment may experience heat cramps (painful muscle spasms). Heat cramps are an early symptom of a more serious problem called HEAT EXHAUSTION. Similar to the symptoms of physical shock to the body, the signs and symptoms of a person suffering from heat exhaustion are dizziness, headache, and nausea. The skin will appear gray in color and will feel cold and clammy. Correct treatment for this condition is the IMMEDIATE removal of the person to a cooler environment. Loosen the clothing and apply cool wet cloths to the head, groin, and ankles. Lightly fan the victim. If the person is conscious, you should make him or her drink cool water. (Do NOT administer more liquid if the victim begins to vomit.) The victim should be transported to a medical facility as soon as possible.

A less common, but far more serious, condition of heat stress is known as HEAT-STROKE. Heatstroke is fatal in about 20 percent of all cases. With heatstroke, the bodys temperature control system completely malfunctions and is unable to rid itself of excess heat. Bodily temperatures may rise as high as 105F (a high fever), and pro-longed high body temperatures can result in failure of vital organs such as the kidneys, liver, and brain. Although the early symptoms of heatstroke appear to be similar to those of heat exhaustion, the symptoms of heat-stroke are distinct. In a victim of heatstroke, breathing becomes shallow, almost absent, as the heat builds up within the body. The skin will appear flushed or reddened and will feel dry and hot. The pupils of the eyes will be constricted to pinpoints, and the pulse will be fast and very strong. Navy personnel must understand that HEATSTROKE IS A TRUE LIFE-AND-DEATH EMERGENCY.

Proper treatment of heatstroke requires immediate action to cool the victims body by moving it to a cooler place and dousing the body with cool water. Remove as much clothing as possible. A conscious victim should be made to drink cool water. Every case of heatstroke must be transported to a medical facility as soon as possible. An important part of the Navys heat stress awareness and prevention program is the constant monitoring of environmental conditions in work spaces, where liquid-in-glass (dry-bulb) thermometers are located at key watch and work stations. The temperature at each work site must be read and recorded at least once per watch. When the temperature in any work space rises to the point where work must be slowed down or curtailed for personnel to avoid heat stress (usually 100F), a heat survey must be taken. Safe stay time limits must then be determined and imposed for people who must continue to work in the space. More information about heat stress awareness and prevention may be found in OPNAV Instruction 5100.20 (latest edition).