98 degree always you and i

Heat stress can cripple you and place your mission at great risk. Who would have thought that something as unexciting as overheating could put you down for the count, or worse, even kill you?

Heat stress includes many conditions where the body is stressed by overheating. There are several different causes of heat stress including high temperatures, heavy workloads, lack of proper hydration and the type of clothing being worn. Roughly three-fourths of the stored energy the body draws on during activity converts to heat rather than motion. The harder you work, the more heat you create. In order to prevent the body from overheating, one must understand how it cools off.

The Body Has Built-in Air Conditioning

There are four ways the body rids itself of heat. This transfer takes place through radiation, evaporation, convection and conduction. Radiation occurs when the body turns heat into electromagnetic waves and the body simply radiates the heat into the air around it. Evaporation is what cools you down when you sweat. Convection and conduction happen after radiation and evaporation. Convection is when the body's heat passes into the air and vapors surrounding the body. Conduction is the transfer of heat through physical contact.

When you are hot, the body tells the brain that its core temperature has risen higher than the normal 98.6 degrees F. The anterior hypothalamus, in the brain, acts like a thermostat for an air conditioner. It signals the body to open up blood vessels near the surface of the skin so that heat can be transferred from the body. This lowers the core body temperature. Sometimes this internal air conditioning system can have adverse affects such as impairing strength and dulling senses. By increasing the blood flow to the body surface, the volume of blood carrying oxygen to muscles, brain, and other internal organs is decreased, which may cause fatigue, blurry vision and diminished alertness. The loss of water volume may thicken the blood, making the heart pump harder. Prolonged sweating reduces the electrolytes that the body needs for proper muscle function. The body's cooling system can even shut down under extreme stress, allowing the body temperature to continuously rise.

A Hot Situation Can Always Get hotter

How many times have you said, "I'm okay, just a little hot"? Well, a "little hot" can go a long way. You simply assume you are feeling a bit ill due to the heat, but you are sweating and that will cool you down, right? Wrong. If you don't replace the water in your body, you may soon become confused and even collapse. Symptoms of heat stress can vary in each individual. Early symptoms of heat stress include dizziness, headache, dry mouth, unsteadiness and muscle pain. Later stages may feature high temperatures, confusion, blurry vision, weak or rapid pulse, convulsions or coma. If you recognize these symptoms, you need to move to a shaded area, drink water, and seek medical attention. The number one defense against heat stress is proper hydration at all times.

Heat stroke is the most serious problem faced by individuals in hot environments. It is a definite, no doubt about it, medical emergency. It is caused by the body's failure to regulate your core temperature. In other words, your internal air conditioning shuts down and the heat just keeps rising. Sweating may stop completely and the body temperature rises well over 104 degrees F. Symptoms can range from confusion to coma. Until a medic can tend to the victim, he or she should be moved to a cool or shaded area and doused in lukewarm water - think of it as artificial sweat cooling down the body. The body should be fanned to speed up the cooling effect. In an emergency, remember to cool first and transport later; if the body temperature is allowed to remain high, brain and vital organs will be damaged. Heat stroke may first start as heat exhaustion or heat cramps. Anyone suspected of heat stroke must see a doctor as soon as possible as his or her condition will deteriorate quickly.

Heat exhaustion happens when you are extremely fatigued and sweating profusely. What has happened inside the body is that it is basically giving out more water than it receives. Nausea, weakness and a headaches signal that the body's water reservoirs are running on "E." The pulse rate may become rapid (120-200 beats per minute) and the body temperature may actually be lower than normal. With heat exhaustion the body's heat balance mechanism is still functioning, but may shut down very soon. The victim should rest, cool down, and drink cool water. Severe cases of heat exhaustion can even lead to loss of consciousness. Both heat exhaustion and heat stroke can easily reoccur as they weaken the temperature regulating system for a long period of time.

Heat cramps are painful spasms in muscles, primarily in the arms, leg and stomach areas. Heat cramps occur when the body loses too much salt. Tired muscles - those working very hard - are the most susceptible to cramping. They can cramp during or after an activity. Replacing missing salts is very important during hot weather activities. Cramps may occur in combination with heat exhaustion. A doctor may decide that an intravenous saline solution is necessary in extreme cases.

Heat syncope is commonly known as fainting. It is easy to tell when someone has fainted, but why did they faint? It usually happens when a person has to stay extremely still for a long time in a hot environment that they are not used to yet. Movement is the main ingredient in preventing fainting, though this may not always be an option in certain situations. Fainting victims usually recover quickly, though they need rest and water to prevent it from happening again.

Heat rash is known by many as "prickly heat." It will make you very uncomfortable, unable to concentrate, and very itchy. It has been described as something that "drives a person absolutely nuts." Left untreated, heat rash may result in a skin infection. Heat rash occurs in hot, humid environments where the skin stays damp. Keeping the skin dry and clean is the best prevention for heat rash. Skin powder and topical medications can provide relief and some victims of heat rash may be placed on an antibiotic.

Heat stress can show itself in many different ways ranging from fatigue to collapse, dehydration to vomiting. Heat stroke, heat exhaustion, heat cramps, fainting and heat rash are all very dangerous results of the body overheating. Heat stroke is the most dangerous level of heat stress and can cause brain damage, organ failure and even death. Heat rash is the least dangerous level of heat stress, causing lack of concentration and possible skin infections.

Staying Cool Requires Planning

The body efficiently manages heat when it is fully hydrated, physically fit, acclimatized, well nourished, and well rested. Each individual body deals with heat differently. Those that are younger and more physically fit are less likely to be hit by heat stress. Individuals with heart, lung or kidney disease, diabetes and those taking medications are at more risk. Caffeine heightens the risk and is often used by many people to jump start their mornings. You are more likely to experience heat stress when first exposed to a new environment and the job is physically demanding. Someone who has not spent a lot of time outdoors may find themselves facing heat stress on their first call out in a heat wave. Once a person has experienced heat stroke or exhaustion, he or she is very susceptible to a second attack.

How hot is hot? It's not just the air temperature you should be watching. There are four environmental characteristics that influence how " hot" it is: air temperature, direct sunlight, humidity, and wind speed. Direct sunlight on bare skin can increase the body's temperature and cause the risk of sunburn. Full sun can be equivalent to a 13 degree increase in air temperature. High humidity decreases the sweat evaporation rate, slowing cooling. Lack of wind can reduce the evaporation rate, also. Air movement affects the body's convective heat transfer; cool winds reduce heat stress, hot winds increase stress.