ehs banner

Occupational Health - Heat Stress

Heat Stress


Heat Stress is the net heat load to which a person may be exposed to from the combined contributions of body (metabolic) heat, environmental factors (temperature, humidity, air movement, and radian heat), and clothing requirement.

Operations involving high air temperatures, radiant heat sources, high humidity, direct physical contact with hot objects, or strenuous physical activities have a high potential for inducing heat stress in a person engaged in such operations. Examples of such operations include: working in foundries, laundries, construction projects, commercial kitchen, boiler rooms, and out-door activities conducted in hot weather, to name but a few.

A mild or moderate heat stress can lead to discomfort and may adversely affect one performance and safety, but is not harmful to one's health. However, as the heat stress approaches human tolerance limits, the risk of heat-related disorders increases.

Heat-Related Disorders

Common heat-related disorders include:

Heat Stroke

Heat Stroke occurs when the body's temperature regulation system fails and the body temperature rises to critical levels. It is caused by a combination of highly variable factors, and its occurrence is difficult to predict. The primary signs and symptoms of heat stroke includes confusion; irrational behavior; loss of consciousness; convulsions; a lack of sweating (usually); hot, dry skin; and an abnormally high body temperature, e.g., a rectal temperature of 41°C (105.8°F).

Heat stroke is a medical emergency: if a person shows signs of possible heat stroke, professional medical treatment should be obtained immediately. A person suffering from heat stroke should be placed in a shady area and the outer clothing should be removed. The person’s skin should be wetted and air movement around the person should be increased to improve evaporative cooling until professional methods of cooling are initiated and the seriousness of the condition can be assessed.

Heat Exhaustion

The signs and symptoms of heat exhaustion include headache, nausea, dizziness, weakness, thirst, and giddiness. Fortunately, heat exhaustion responds readily to prompt treatment. However, heat exhaustion should not be dismissed lightly. A person suffering from heat exhaustion should be removed from the hot environment and given fluid replacement and encouraged to get adequate rest.

Heat Cramps

Heat Cramps are usually caused by performing hard physical labor in a hot environment. These cramps have been attributed to an electrolyte imbalance—too much and too little salt, caused by sweating. Cramps appear to be caused by the lack of water replenishment. Thirst cannot be relied on as a guide to the need for water; instead, water must be taken every 15 to 20 minutes in hot environments.

Heat Collapse ("Fainting")

Heat collapse occurs when the brain does not receive enough oxygen because blood pools in the extremities. As a result, the exposed individual may lose consciousness. This reaction is similar to that of heat exhaustion and does not affect the body's heat balance. However, the onset of heat collapse is rapid and unpredictable. To prevent heat collapse, a person should be gradually acclimatized to the hot environment.

Heat Rashes

Heat rashes are the most common problem in hot work environments. It manifest as red papules which usually appears in areas where the clothing is restrictive. As sweating increases, these papules give rise to a prickling sensation. In most cases, heat rashes will disappear when the affected individual returns to a cool environment.

Heat Fatigue

The signs and symptoms of heat fatigue include impaired performance of skilled sensorimotor, mental, or vigilance jobs. There is no treatment for heat fatigue except to remove the heat stress before a more serious heat-related condition develops. A factor that predisposes an individual to heat fatigue is lack of acclimatization. The use of a program of acclimatization and training for work in hot environments is advisable.


Chemical Inventory


Material Safety Datasheet (MSDS)

Search For MSDS


Currently No Student Vacancies.

Please check back for openings

EHS Training

Online Training


EHS - General

Tel: 770-499-3321

Fax: 770-420-4363


Campus Emergency

Dial - 6666