The body's initial reaction to temperature rises is to lower internal body temperature by increasing the blood circulation to the skin so that excess heat can escape through the skin. But if the body's muscles are being used for physical activity, less blood is available to flow to the skin.
Sweating is another way the body releases heat. When increased blood flow does not lower the core temperature, the body will produce sweat. When this moisture reaches the skin surface, it evaporates and cools the body down. Sweating is only effective if humidity levels are low enough to allow evaporation to take place, and if the fluids lost by the body are replaced.
If the body cannot reduce its temperature through increased blood circulation and sweating, it will begin to store the heat. When this happens, you run the risk of serious health hazards.
When you continue to labor at the same pace in growing heat, your body loses fluids and becomes fatigued. The increasing heat stress results in poorer job performance by lowering your alertness and slowing physical responses. As the brain loses vital blood fuel that has gone off to fight the heat, you may no longer be able to even recognize your body's natural warning symptoms.
Symptoms of heat-related illnesses can range from rashes and sunburns to cramps, exhaustion, and heat stroke. Heat rashes, sunburns, and heat cramps can be painful and uncomfortable, but they are not life threatening. Heat exhaustion and heat stroke are more serious conditions. If a co-worker suffers from a heat illness, your ability to recognize the symptoms and apply the proper treatment can be vital to saving a life. Let us take a closer look at some of the physical symptoms.
Early warnings of approaching heat stress often are overlooked as routine heat discomfort. An example is heat rash. Some call it "prickly heat," which develops when the skin remains wet, as sweat does not evaporate. It's common during humid periods of heat when sweat on the skin is slow at evaporating. This clogs the sweat ducts, and a skin rash appears. Relief comes from bathing the affected areas, then drying the skin. Heat rash involves discomfort more than danger.
Fainting and fatigue
If you feel dizzy or faint, it likely is a result of standing upright and motionless in the heat. Not moving causes blood to pool-a tendency for blood to flow through heat-enlarged blood vessels and collect in the lower areas of the body, leaving the brain without adequate replenishment. Often walking or moving around can offset the dizziness. At the first sign of dizziness or fainting, lie down. If that is not possible, sit down and put your head between your legs. As your head clears, get back on your feet and start moving around to prevent continued blood pooling. In any case, don't ignore any bodily warnings, as they can lead to more serious levels of heat stress:
Heat cramps are painful muscle spasms that are caused by lack of salt in the body. They usually result from sweating heavily and drinking large amounts of water without replacing the body's salt loss. While water is needed to keep the body from dehydrating, drinking large quantities of it dilutes the body's fluids. This shortage of salt in the muscles causes sudden, painful spasms in the affected areas. Cramps usually affect tired muscles first, and sometimes don't hit until after work hours. Cramps may hurt, but they alert you that you need to ease up the work pace before the problem advances to the more dangerous areas of heat exhaustion and stroke. Replace the salt your body has lost by drinking a .5 percent solution of salt water or a sports drink. Rest in a cool place away from the sun. Lightly massaging the cramped muscles can bring some relief.
Continued loss of fluid and salt from sweating can lead to heat exhaustion. The victim sometimes mistakes the symptoms for the flu. Symptoms can include heavy sweating, cool and moist skin, and a weak pulse. Other symptoms can include possible fainting, weakness, dizziness, nausea, diarrhea, blurred vision, and a normal or slightly high body temperature. The advanced stages of heat exhaustion can cause vomiting or loss of consciousness.