Heat stress is the effect that the thermal environment has on a person’s ability to maintain a normal body temperature. Physical work generates heat in the body which must be lost to the environment through sweating and evaporation. A hot or humid environment makes this more difficult and this can affect both mental and physical performance. Inability to get rid of body heat adequately may result in heat illness.
Heat-related disorders and diseases
Prickly heat rash: Heat rashes exhibit as red spots on the skin that cause a prickling sensation during heat exposure.
Heat cramps are often the first indicator of a heat-related problem. Symptoms are sharp and painful spasms in the muscles that are being stressed in hot environments, mostly calves, arms, abdominal wall and back. Heat cramps usually occur in unacclimatised workers who have replaced water lost through sweating but who have not replaced salt at the same time.
Heat exhaustion often begins suddenly, sometimes after excessive exercise or work, heavy sweating (with fluid and salt loss) and inadequate fluid and electrolyte intake. It can precede heat stroke and is characterized by heavy sweating but with cool, moist and pale skin. Dizziness, blurred vision and unconsciousness may accompany a rapid but weak pulse and low blood pressure. Low-grade fever, headache, confusion, fatigue, nausea, heat cramps, rapid breathing and dark-colored urine may also be present.
Heat stroke is the most serious heat illness, often resulting from exercise or heavy or prolonged work in hot environments with inadequate fluid intake. What makes heatstroke severe and potentially life-threatening is that the body's normal mechanisms for dealing with heat stress, such as sweating and temperature control, are lost. Main symptoms of heat stroke are elevated body temperature (> 40 °C), hot and dry skin (sweating stops), and central nervous system dysfunction, ranging from headache, Irritability, dizziness, confusion, personality changes to partial or complete loss of consciousness (coma). A rapid heartbeat, rapid shallow breathing and nausea can also be present. Heat stroke can be fatal and requires prompt medical attention.