Summer Heat Health Tips

September 8, 2010
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Camping is certainly an enjoyable way to create memories with family and friends. Outdoor activities — such as sightseeing, hiking, fishing and biking — all require physical exertion, and all that time in the summer heat can cause you to become dehydrated, which can lead to more serious problems like heat cramps, heat exhaustion, or heat stroke. So before heading into the great outdoors, prepare yourself and your family against the dangers of dehydration and overheating.

What Is Dehydration?

When your body loses water and fluids without being replaced, dehydration occurs. Sweat, our natural cooling system, takes water out of our bodies to lower our skin temperature. We feel the “cool” when sweat evaporates off our skin. Over time, we need to replace the fluids lost through sweat; otherwise, sweat production will be limited or absent. Without sweat, the body can’t lower its temperature and we become overheated (hyperthermic). A common way for healthy individuals to become dehydrated is simply not drinking enough fluids prior to being out in the heat.

Dehydration not only impacts your body temperature, but it can also affect your body chemistry. When you sweat, in addition to water, electrolytes such as sodium and potassium are lost. The typical American diet already consumes plenty of electrolytes so it isn’t as important to consume them prior to exercise compared to water. However, when you sweat in great amounts — during, say, an afternoon hike — you may need to replace them by consuming a sports drink or potassium-rich food like a banana or kiwi. Otherwise you’ll risk muscle cramps or spasm, which might cut short your activity.

Other factors that can worsen or make someone more prone to dehydration include diarrhea, vomiting, burns and diabetes.

Dehydration Signals

Thirst is the most obvious sign of dehydration, but it can be a poor signal because it usually presents itself after you are dehydrated. Typically, thirst occurs after you lose 1 to 2 percent of body weight in fluids, which is significant (as little as

3 percent can lead to heat-related illness). For this reason, it is imperative to drink plenty of fluids before you feel thirsty.

Another easy way to tell if you are dehydrated is to look at the color of your urine. If your urine is clear, chances are you are well hydrated. If it’s yellow, dark yellow or amber in color, you are dehydrated. Other signs of dehydration include but are not limited to dry mouth, extreme fatigue, breathlessness, dizziness, vomiting, fainting, cold clammy skin or hot dry skin, aggressiveness, dis­orientation, rapid pulse, and emotional instability.

While we may not think of camping as a professional sport in terms of physical exertion, hyperthermia is still a potent danger when spending long days in the sun.

Three common symptoms are associated with hyperthermia: heat cramps, heat exhaustion, and heat stroke. Each of these illnesses can occur with little to no warning and independent of each other. For example, you may experience heat stroke without any symptoms of heat exhaustion or heat cramps. This makes it very difficult to predict the onset of hyperthermia. Each illness is caused by dehydration but each has a different set of characteristics.

Heat cramps occur when your body is still able to produce sweat, but a lack of electrolytes causes your muscles to cramp or spasm, often painfully. Heat cramps are treated with the consumption of water or a sports drink with electrolytes, and then applying a light massage to the affected muscle. It is important to allow your body to cool down in the shade or in air conditioning before resuming activity.

Heat exhaustion exhibits a range of signs and symptoms, which include (but are not limited to): extreme fatigue, breathlessness, dizziness, vomiting, fainting, clammy skin, or hot dry skin. People suffering heat exhaustion often report feeling “overwhelmed” by the heat. More serious than heat cramps, it is imperative to move people into a cooler environment and to replenish with water. In addition, it is helpful to bring down body temperature by loosening clothes, sponging with cool water while fanning the person, or applying ice packs to various parts of the body. You should also contact emergency medical services to decrease the risk of this situation becoming more severe.

Heat stroke is a life-threatening condition caused by severe water depletion. During heat stroke, the body is unable to cool itself and sweating may stop altogether. If you are out in the sun and not sweating, always suspect the onset of heat stress, which can lead to heat stroke. People suffering from heat stroke show symptoms including (but not limited to): aggressiveness, disorientation, hot and dry skin, rapid pulse, and emotional instability. As with heat exhaustion, it is imperative to get out of the heat, consume water, and contact emergency medical services (911) immediately. While waiting for the ambulance to arrive, use any method available (spraying them with a garden hose, fanning, shade) to cool the individual. Treat them for potential shock by elevating their legs.

For each of these illnesses con­sider how clothing might be affecting the problem. Clothing that is soaked in sweat limits evaporation even more. You should always keep a dry shirt with you for changing, particularly if you go far from home base, such as on a long hike, or even a short one in hot muggy weather.

Prevention: The Best Medicine

Before venturing out, take time to check the weather conditions. Check both the temperature and relative humidity for various times during the day. If the relative humidity is high, our body’s capacity to lose heat through evaporation decreases. The higher the humidity level, the hotter your body will feel. For instance, if you decide to go for a hike on a nice 82-degree day with the relative humidity level at 87 percent, the perceptible temperature will be about 90 degrees F. Humans are most comfortable when humidity is around 45 percent. The closer the relative humidity is to 100 percent, the more difficult it is for sweat to evaporate from our body.

Drink plenty of fluids. But what should you drink? Plain old-fashioned water is still the best way to stay hydrated. Our diets tend to provide the electrolytes we need, so water is almost always the best option for basic hydration as opposed to juices and other such beverages.

Many factors impact the amount of water you should drink, such as physical activity, air temperature, health status, and body size. On average, a woman should consume nine cups of water per day and men 13. However, as you exercise and perspire in the heat, that requirement increases.

Sports drinks (Gatorade, Powerade, etc.) are typically recommended when physical activity exceeds 60 minutes. These drinks are designed to replace fluid and electrolytes lost through sweat, and even give you an energy boost, which may help fight fatigue. When choosing a sports drink, be sure that it contains at least 6 percent carbohydrate in the form of glucose, sucrose, or fructose (sugars). These sugars give you immediate energy.

What to Avoid

Avoid sports drinks that contain only fructose as a sugar, and be sure it contains some sodium content to replace electrolytes. You also want to avoid sports drinks that are carbonated and/or contain caffeine.

Today’s advertising overwhelms us with a range of sports drinks, many promising everything from a longer life to building muscle. But for hydration purposes, you should avoid beverages that contain caffeine such as coffee, iced tea, and pop along with energy drinks. Caffeine is a diuretic and works against you when you are trying to hydrate yourself.

Stay away from alcohol, as it increases urine output and leads to dehydration. Carbonated beverages may cause stomach discomfort and fruit juices can lead to heartburn and contain too many carbohydrates. If you do choose a fruit juice, dilute it with water.

Hydration Schedule

The amount of fluid you should consume in the heat during physical activity varies. Important factors to consider include exertion level, humidity, and length of activity. As a good rule of thumb, consider the following guidelines.

Consume about 17 to 20 ounces of fluid two to three hours before any activity, and then another 7 to 10 ounces 10 to 20 minutes before the activity begins. During activity, consume 7 to 10 ounces every 10 to 15 minutes. Be sure to hydrate again when the activity is over. Another good rule is to consume approximately 20 ounces of fluid per pound of weight loss. This should be consumed within two hours following activity. One gulp of fluid is approximately 1 ounce.

With safety and prevention in mind, dehydration and heat illnesses can be avoided. Plan ahead. Check the weather, bring water, and if you intend to spend extended hours in the sun, consume plenty of fluids the day before.

Camping brings hours of family fun, but that fun can cause us to forget the toll of heat and sun on our bodies. Hiking, biking, kayaking, etc. — all offer hours of fun, but they’re only enjoyable when properly hydrated. Remember, as long as you prepare for the heat, there’s less chance of spoiling your fun.

This article is for general information purposes only, and is not intended to diagnose any condition you may be feeling or treating.

If you have questions about medical needs, consult your physician immediately. We encourage you to participate in first-aid and CPR training through local public education or the American Red Cross.

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