Скачать или смотреть Heat Stress Research 1950s

Heat can kill workers if precautions are not taken. This clip was taken from a 1950s newsreel as early research into heat stress was just beginning. Four environmental factors affect the amount of stress a worker faces in a hot work area: temperature, humidity, radiant heat (such as from the sun or a furnace) and wind speed. Individuals with high blood pressure or some heart conditions and people who take water pills may be more sensitive to heat exposure. The body defends itself from heat through three mechanisms: breathing, sweating, and changing the blood flow. The first reaction is to circulate blood to the skin, which increases skin temperature and allows the body to give off some heat. During heavy work, muscles need more blood flow, which reduces the amount of blood available to flow to the skin and release the heat. Sweating also helps the body to cool off, but only when the humidity levels are low enough to allow the sweat to evaporate and if water and salts lost through sweating are replaced. When the body becomes overheated, a condition of heat stress exists. Heat stress can lead to a number of problems, including heat exhaustion, heat stroke, heat cramps, fainting, or heat rash. For more about heat stress and its prevention at work, check out the Washington State Department of Labor and Industries website at: http://www.lni.wa.gov/Safety/Research...