Heat Stroke and Other Heat-Related Illnesses

Hot humid weather can cause additional stress to employees while working, and using personal protective equipment in these conditions can exasperate that stress. It is important that you learn to recognize the signs of heat stress and recognize when you are overheated and in need of medical attention.

While working in hot weather conditions, the body may not be able to maintain a normal temperature simply by sweating. If this happens, heat-related illnesses may occur. The most common health problems caused by hot work environments include:

Heat stroke – This is the most serious heat-related effect. Heat stroke occurs when the body temperature increases above 104°F. Signs and symptoms of heat stroke are confusion, loss of consciousness, seizures, and lack of perspiration. This condition must be treated as a medical emergency, and the employee must receive immediate medical attention.

Heat exhaustion – Signs and symptoms of heat exhaustion include headache, nausea, dizziness, weakness, irritability, confusion, thirst, heavy perspiration and a body temperature greater than 100.4°F. Employees experiencing heat exhaustion should be moved to a cool area and given fluids to drink and cold compresses for their head, face, and neck. Employees should be taken to a clinic or emergency room to be monitored by medical personnel.

Heat cramps – Signs and symptoms of heat cramps include muscle pains usually caused by the loss of body salts and/or fluids. This can happen later also. Employees should replace fluid loss by drinking water and/or carbohydrate-electrolyte replacement liquids (e.g., Gatorade) every 15 to 20 minutes.

Heat rash – Heat rash is caused by excessive perspiration and looks presents as a red cluster of pimples or small blisters. Heat rash usually appears on the neck, upper chest, in the groin, under the breasts, and in elbow creases. Treatment for heat rash is to provide a cooler, less humid environment.

Dehydration – Dehydration is a major factor in most heat disorders. Signs and symptoms of dehydration include increasing thirst, dry mouth, weakness or light-headedness (particularly if worse upon standing), and a darkening of the urine or a decrease in urination. Dehydration can be reversed or put back in balance by drinking fluids that contain electrolytes (i.e., Gatorade) that are lost during work-related activities. Avoid caffeinated drinks.

Here are some things to think about when working in hot environments:

  • Exposure to a hot work environment requires that workers be continuously hydrated. Be sure to take breaks and drink as much water as necessary to stay hydrated.
  • Try to limit exposure time. Schedule as many hot activities as practical for the coolest part of the day (early morning or late afternoon).
  • Take rest breaks at frequent regular intervals, preferably in a cool environment sheltered from direct sunlight. Anyone experiencing extreme heat discomfort should rest immediately.
  • Wear loose-fitting clothing that is permeable to air. Generally, less clothing is desirable in hot environments, except when a person is standing next to a radiant heat source. In that case, covering exposed skin is beneficial to reducing heat stress. Be sure to follow departmental uniform guidelines.

The OSHA Heat Index was developed to assign protective measures for workers in hot environments.

Occupational Heat Exposure