Fluids key to managing heat

MANHATTAN, Kan. – It’s a good thing water bottles have become ‘cool’ – the contents of the stylish containers can make coping with high heat and humidity easier.

They also can protect outdoor workers, athletes, exercise enthusiasts, older adults, and children at play from summertime health risks that can be deadly, said Mary Higgins, K-State Research and Extension nutrition specialist.

Mostly water. Fifty-five to 75 percent of the body’s weight is water; the brain is 70 percent water; blood is 82 percent water; and the lungs are nearly 90 percent water.

The refreshing liquid carries nutrients and oxygen to cells; cushions organs, tissue, bones and joints; removes wastes; and also regulates body temperature.

Excessive water loss (dehydration) can impair body function and lead to heat exhaustion and/or heat stroke that can be life threatening, she said.

Body loses H2O. Water is lost through perspiration and elimination. In high heat, humidity, or times of high activity (like working outdoors or participating in athletic activities), perspiration, which cools the body through evaporation of fluids, increases.

Exposure to the sun or a sunburn can speed fluid loss; so can beverages with caffeine, which acts as a diuretic.

“Fluid replacement is essential, but it’s best not to wait until you’re thirsty. People often become slightly dehydrated before they become thirsty,” Higgins said.

Are you dehydrated. Checking to see if your body is well hydrated is easy – just look at your urine. If urine is pale yellow in color, fluids would appear to be adequate. If urine is dark yellow or appears concentrated, more fluids are needed, she said.

Eight to 12 cups of fluid are recommended each day to replenish essential body fluids. Water is recommended as a majority of the fluid replacement because it is readily absorbed.

Cool water is preferred because it is absorbed more readily than warm, hot or ice water.

Where to get fluids. “Some fluid replacement can come from other sources, such as milk; 100 percent fruit juice; low-sodium vegetable juice; foods that have a high water content, like fruits (melons) and vegetables (celery or tomatoes); or foods made with fluids (milk, fruit juices or soup broths, for example), such as puddings, gelatin salads or soups,” the nutrition specialist said.

Beverages that contain alcohol, which acts as a diuretic that speeds fluid loss, are not recommended as essential fluid replacements.

Sports beverages may be helpful to some athletes who are exercising more than one hour and in need of quick energy, but Higgins recommends diluting them with an equal part of water to help replenish fluids and reduce calories.

How much do you need? Replenishing fluids is recommended for everyone. Before working in the heat, exercising or participating in athletics, Higgins recommends drinking 14-22 ounces of cool water.

In order to make sure that people who work outdoors, athletes and/or active children get enough fluids to replenish fluid loss, Higgins suggests weighing before and after an activity and drinking 16-24 ounces of water for each pound lost.