Weather, climate and temperature can all play a significant role in a person's health.
"Most people feel comfortable when the air temperature ranges between 68F and 80F, and the relative humidity is between 35 to 60 percent," explained Family Medicine physician Tim Wagner, D.O. "However, when air temperature or humidity reaches higher levels, people may feel discomfort as their body tries to adjust to the warmer environment."
Body temperature is a measure of the body's ability to generate and get rid of heat. The body is very good at keeping its temperature within a narrow, safe range averaging 98.60F, in spite of temperature changes occurring in the environment.
"When you are too hot, the blood vessels in your skin expand or dilate to carry the excess heat to your skin's surface," Dr. Wagner said. "You may begin to sweat, and as the sweat evaporates, it helps cool your body. When you are too cold, your blood vessels narrow or contract, so that blood flow to your skin is reduced to conserve body heat. You may start shivering, which is an involuntary, rapid contraction of the muscles. This extra muscle activity helps generate more heat. Under normal conditions, these actions help keep your body temperature within a safe range.
"However, in a very hot environment, the rate of heat gain starts to exceed the rate of heat loss, and body temperature begins to rise. Changes in blood flow and excessive sweating can then reduce a person's ability to perform physical and mental activities."
Risk Factors for Heat-related Illnesses
"A heat-related illness occurs when our bodies can no longer transfer enough heat to keep us cool," Dr. Wagner added. "A high body temperature, also known as hyperthermia, can develop rapidly in extremely hot environments, such as when a child is left in a car in the summer heat or if a person is working in a small space with poor ventilation. The risk of heat-related illness varies from person-to-person, and there are several factors that may influence how people adapt to warmer temperatures."
- Age: Babies don't lose heat quickly or sweat effectively. Older adults do not sweat easily and usually have other health conditions that affect their ability to lose heat.
- Obesity: People who are overweight have decreased blood flow to the skin, hold heat in because of the insulating layer of fat tissue, and have a greater body mass to cool.
- Chronic diseases, such as diabetes, heart failure, cancer, or skin diseases and rashes may change the way the body gets rid of heat.
- Exercising during hot weather, working outdoors, and overdressing for the environment increase your risk.
- Caffeine or alcohol use increases the risk of dehydration.
- Medications: Some medicines decrease the amount of blood pumped by the heart and limit blood flow to the skin, so the body is less able to cool itself. Other medicines can alter your sense of thirst or increase your body's production of heat.
"If you take medicines regularly, ask your physician about how hot weather activities may affect your risk for a heat-related illness," Dr. Wagner suggested.
Illnesses Related to Heat Exposure
As people perform outdoor activities, they can develop heat-related illnesses, such as:
- Heat edema: Swelling which generally occurs among people who are not used to being in hot conditions. Swelling is often most noticeable in the ankles.
- Heat rashes: Tiny red spots on the skin which cause a prickling sensation during heat exposure. The spots are the result of inflammation caused when the ducts of sweat glands become plugged.
- Heat cramps: Sharp pains in the muscles that may occur alone or be combined with one of the other heat stress disorders. The cause is salt imbalance resulting from the failure to replace salt lost with sweat. Cramps most often occur when people drink large amounts of water without sufficient salt (electrolyte) replacement.
- Heat exhaustion: Caused by loss of body water and salt through excessive sweating. Signs of heat exhaustion include: heavy sweating, weakness, dizziness, visual disturbances, intense thirst, nausea, headache, vomiting, diarrhea, muscle cramps, breathlessness, palpitations, tingling and numbness of the hands and feet.
- Heat syncope: Heat-induced giddiness and fainting induced by temporarily insufficient flow of blood to the brain while a person is standing. It is caused by the loss of body fluids through sweating, and by lowered blood pressure due to pooling of blood in the legs.
- Heatstroke: Occurs when the body fails to regulate its own temperature and body temperature continues to rise. Symptoms of heatstroke include mental changes (such as confusion or unconsciousness) and skin that is red, hot, and dry, even under the armpits.
Classic heatstroke can develop without exertion when the body is unable to cool itself effectively. In this type of heatstroke, the body's ability to sweat and transfer the heat to the environment is reduced. Exertional heatstroke may develop when a person is working or exercising in a hot environment and may sweat profusely, but the body still produces more heat than it can lose. Both types of heatstroke cause severe dehydration and may cause body organs to stop functioning.
"Home treatment is usually all that is needed to treat mild heat-related illnesses," Dr. Wagner concluded. "But, heat exhaustion and heatstroke need immediate first aid and medicalattention."
Tim Wagner, D.O., is board certified in Family Practice, and a member of Salem Community Hospital's medical staff. He is affiliated with Firestone Health Care, with offices located at 28885 State Route 62 in Damascus, 330-537-4661; 132 N. Market Street in East Palestine, 330-426-9484; and 2364 Southeast Boulevard in Salem, 330-332-4833.