Exposure to extreme heat or working in a hot environment indoors or outdoors puts a toll on the human body. When combined with strenuous physical activities, humidity, poor hydration practices, or personal health factors (such as medications, illness, pre-existing medical conditions, or being overweight), that toll can quickly lead to a serious injury or fatality from a heat-related illness (HRI). HRIs occur when the body becomes unable to properly cool, resulting in a rapid rise in body temperature, or hyperthermia. HRIs include heat rash, heat cramps, heat syncope (fainting), rhabdomyolysis (death of muscle fiber), heat exhaustion or heat stroke.
While HRIs present a direct health concern, the physical symptoms of heat stress also elevate risk factors that can lead a worker to suffer other acute, traumatic injuries. These symptoms include a loss of balance, reduced mental awareness/focus, loss of grip, a decrease in reaction time, and general fatigue/muscle weakness. These physical states not only put the worker at risk, but possibly fellow co-workers and the public. Managing heat-related risk, whether from work outdoors or inside, is an essential part of an overall safety plan to prevent work-related injuries.