Summer weather means Mother Nature can really turn up the heat. Although heat itself can cause problems, humidity, in addition to heat, significantly increases the overall heat stress on your body.
Weather forecasters use the term dew point to indicate the amount of moisture in the air. Dew points in the 50s and low 60s reflect fairly comfortable heat. Dew points in the upper 60s and low 70s refer to very muggy air that can both increase the effect of heat on your body and exaggerate air quality conditions like smog and airborne allergens.
One of your body’s first natural responses to heat is perspiration. This process allows your body to cool off by having moisture evaporate from the skin, taking some of the body heat with it. If you become hot, either playing a sport or just trying to stay cool on a hot day, you need to perspire. In a dangerous situation called heat stoke, an individual’s body doesn’t properly respond to increased body temperature by perspiring, and medical attention is usually required.
Although perspiration is necessary, it can often lead to another hot weather condition, dehydration. Dehydration occurs when the body loses more fluid than it takes in. Under normal conditions, you should drink from 6 to 8 eight-ounce glasses of water a day. This amount must increase in the heat or with exercise or other physical activity.
Patients often say, “I only drink when I’m thirsty,” but thirst is a poor indicator of when to drink. In some individuals the thirst mechanism doesn’t appear to function, and in others thirst occurs well into the dehydration process. A large number of people actually are somewhat dehydrated all the time. When they then find themselves in situations taxing their reserves, they can dehydrate a lot, and fast.
Symptoms of dehydration include a sense of fatigue, joint pain similar to arthritis, and dizziness, headache, nausea and disorientation. Other signs include a decrease in urine output and darker colored urine. Another way you can tell if you are dehydrated is called checking skin turgor. In a normal adult, this is done by pinching skin on the back of the hand for a moment, and then letting it go. The skin should quickly return to its original state. The slower it returns, the greater the degree of dehydration.
Clinically, mild dehydration occurs if you have lost 3%-5% of your body weight in fluids, moderate dehydration is a loss of 6%-10% of your body weight and life-threatening dehydration occurs with a 9%-15% loss of body weight.
Other factors leading to dehydration include drinking diuretic liquids (substances causing you to lose fluids). These include liquids with either caffeine or alcohol. So, despite the commercials, the worst thing you can do is drink a beer or caffeinated soda on a hot day while you work or play outside!
Along with water loss, perspiration can also cause a drop in certain minerals called electrolytes, which your body needs to function properly. Spasms and cramping in the muscles, usually of the legs, can result. Most people have more than enough salt in their diets to make up for lost sodium, but consuming bananas or orange juice helpfully replaces lost potassium.
In hot weather remember to limit outside activity and exercise to morning and late afternoons and use plenty of sunscreen. Drink lots of water and stay cool by wetting down your hair and skin, using a fan or staying in the shade. Better yet, stay in air conditioning.
Be smart when it’s hot! It’s the cool thing to do.