Published: August 05, 2008 10:00 am         

Weathering the heat

Keep a water bottle handy. It’s not getting any cooler out there.

Hot, dry summer days should be reminding each of us to pay special attention to our own fluid intakes. Whether you are outside on the job or for recreation, it is important to keep a water bottle handy at all times.

Adults should closely monitor the children in their care as well, and see that they drink water throughout the day.

As a nutrient, one of the important roles for water is to regulate core body temperature. It takes only a few minutes in the hot outdoors before you begin sweating. The moisture on your skin helps to cool you down as the air moves over your body. The cooling action is good but you are losing water from your body that will need to be replaced.

Unless that water is replaced, you risk disrupting this important cooling mechanism. Unreplaced water loss can result in fatigue, nausea, headaches and dizziness. Severe water loss can lead to heat stroke and even death.

Most people will need from 8-12 cups of water daily, from drinking water, other beverages and water contained in foods. When you don’t get enough water, your body will trigger a sense of thirst. However, during hot weather, drink water before you feel thirsty to avoid the signs of water deprivation. The best fluid replacement is plain, cool water but other fluids will work, too. Beverages with caffeine are not the best choice for replacing lost water because caffeine increases water loss through urination.

Are you getting enough fluids? To make sure you are getting enough water, you can monitor your body in the following ways:

• Check your urine. If your urine is dark yellow or amber in color or small in quantity, it is likely concentrated with metabolic wastes, and you need to drink more fluids. Your urine should be a pale yellow color and normal quantity when you are getting enough fluids. If you are not going to the bathroom every 2-4 hours, you are not drinking enough.

• Weigh yourself. By weighing yourself before and after work or exercise, you can monitor the pounds lost during your activity. For every pound lost, you should drink at least 2 cups of fluid. In hot weather, those who work outside or exercise may find that they’ve sweat off as much as 5-8 pounds. This is water loss, not fat loss.

• Monitor your feelings. If you feel chronically fatigued, lethargic, or have a constant headache, you may be dehydrated. Monitor yourself and others for impaired performance, heat cramps, chills, clammy skin, rapid pulse, gastrointestinal problems, dizziness, dry mouth, hallucinations, no sweat or urine, swollen tongue, unsteady walk, high body temperature, refusal of water, vomiting and changes in levels of consciousness. These may all be signs and symptoms of sever heat problems.

In addition to getting enough fluid, getting the right type of fluid is important. A rule of thumb is to try to drink 4 to 8 ounces ( 1/2 to 1 cup ) of cool water every 15 minutes during work or exercise in a hot environment to prevent dehydration. Cold fluids seem to be absorbed more rapidly from the stomach than those that are warm or room temperature.

Commercial sports drinks can help to replace fluids, but they should not contain more than 6-8 percent glucose or be high in fructose. Glucose concentrations higher than 8 percent will slow down water absorption when working or exercising in the heat. You can also make homemade sports drinks.

In the box below you’ll find a recipe for a homemade sports drink that will work as effectively as store bought drinks, but it costs a lot less.

Soft drinks and energy drinks (like Red Bull and Atomic Energy ) contain glucose levels that are too high for proper rehydration during work or exercise in the heat. For example, the average soft drink contains between 10-12 percent glucose.

Salt or salt solution consumption is not necessary. The concentration of sodium in your blood actually increases during exercise because you lose proportionately more water than sodium. Your first need is to replace fluids. You will get adequate sodium in the foods you eat. In one study, even athletes who lost 6 percent of their body weight only lost 1 to 2 teaspoons of salt.

Additionally, the less salt you eat, the less you lose because kidneys and sweat glands tend to conserve sodium when it is in short supply.

     

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