News Release Distributed 06/07/11

Excessively hot weather can lead to an increased risk of dehydration, especially in older adults. Dehydration – the reduction of total body water – may result from an insufficient intake of fluids and/or fluid loss.

“Older people are at high risk for developing heat-related illness because the ability to respond to summer heat can become less efficient with advancing years,” says LSU AgCenter nutritionist Beth Reames. “Studies show senior citizens may not drink sufficient fluids, and they also may be taking medications, such as diuretics for high blood pressure, which cause fluid loss.”

Lifestyle factors that also can increase dehydration risks include extremely hot living quarters, lack of transportation, overdressing, visiting overcrowded places and not understanding weather conditions.

Symptoms of heat-related illnesses may include headache, nausea, muscle spasms and fatigue after exposure to heat, Reames says.

“Both an individual's general health and lifestyle may increase the threat of a heat-related illness,” she says. “Even small losses of body water can impair activity and judgment. Dehydration may increase the severity of an illness as well as the risk of death.”

Studies show that most healthy adults are adequately hydrated. The Food and Nutrition Board of the Institute of Medicine recommends approximately 11 cups of total water from all beverages and food for women and 16 cups for men each day.

People get water from both beverages and food, Reames says. About 80 percent of people's total water intake comes from drinking water and beverages – including caffeinated beverages – and the other 20 percent comes from food. Solid foods may contribute about four to five cups of water each day, and many fruits and vegetables are 90 percent fluid.

Although most people can meet their fluid needs by drinking when they’re thirsty and regularly consuming beverages at meals, prolonged physical activity and heat exposure will increase water losses and may raise daily fluid needs.

“In very hot weather, very active individuals often have daily total water needs of six quarts or more, according to several studies,” Reames says. “In addition to physical activity and environmental conditions, diet, disease and health conditions along with the use of diuretics and other medications can affect water needs. It’s also important to remember that water needs vary from day to day.”

Research now shows that drinking caffeinated beverages doesn’t lead to dehydration, the nutritionist adds. According to the Food and Nutrition Board, people can meet their hydration needs by drinking caffeinated beverages along with other beverages and foods. Some beverages, especially those containing alcohol, however, may lead to loss of body water.

Reames offers the following tips to help people get enough fluids, especially in hot weather:

– Water is a great fluid replacer. Drink cool water because it’s absorbed faster, and you’ll usually drink more of it because it tastes better. It’s also calorie-free.

– Try drinking fruit juice diluted with plain water or sparkling water for a refreshing lift.

– Besides water, fluid can come from all kinds of beverages and food, including juice, milk, soup, tea, coffee and soft drinks. Fruits like watermelon and cantaloupe have high water content. So do frozen treats like 100-percent fruit juice pops.