OSU nutrition expert offers tips on dehydration, heat exhaustion

Jun. 28—With temperatures reaching triple-digit degrees this week, Stillwater residents may become dehydrated and suffer from heatstroke before they even realize what's happening.

Oklahomans — particularly the elderly and young children — need to have someone watch out for the signs of dehydration and heat exhaustion, but everyone needs to be aware of them.

Thirst is the first sign of dehydration, said Janice Hermann, an Oklahoma State University Extension adult nutrition specialist and a professor of nutritional sciences.

"Thirst actually slags behind your need for water," Hermann said.

Which means, if a person is thirsty, their body is already showing signs of dehydration.

As an educator and nutrition specialist for 38 years, Hermann knows firsthand the effects that hot, humid weather can have on Oklahomans. She said it only takes about a 2 percent loss of body water for someone to have reduced capacity, and a 7 percent loss of body water can lead to a person collapsing.

"If you think about that — for a 150-pound person, a two percent body weight loss is about three pounds, and a seven percent loss of weight is about 10.5 pounds," Hermann said.

For the average adult, 60 percent of the body is composed of water, so it doesn't take long to be affected by a lack of water consumption.

"We're more water than anything," Hermann said. "And a 1 to 2 percent loss of body water is going to result in thirst."

From there, adults can experience fatigue, weakness and loss of appetite.

A 3 to 4 percent loss of body water can result in an impaired ability to perform, reduction in urine, dry mouth and flushed skin. A 5 to 6 percent loss of body water leads to difficulty in concentrating, headaches, irritability and impaired body temperature regulation.

At 7 to 10 percent loss of body water can lead to dizziness, muscle spasms, delirium, exhaustion or collapse.

"When you think about it, people will die of a lack of water long before they'll die from a lack of food," Hermann said. "You need water for almost every mechanism occurring in the body. Water is just super critical for all the body's function."

Dietary Reference Intakes Nutrition, or scientifically developed reference values, sets the recommendations for nutrients for nutrition professionals, governments and non-governmental organizations.

Their research suggest that the adequate intake for water for adult males is 3 liters, or 13 cups per day and 2.2 liters, or 9 cups for adult females. The rest of the water needed, about 20 percent, comes from food intake of an average 2,000-calorie diet.

But Hermann said more water is needed if a person is increasing activity or is in a hot, humid environment. The human body will cool itself or regulate its temperature through the skin by sweating, but this does not work in extremely hot or humid conditions.

"In the hot, humid conditions — particularly humid conditions — sweat doesn't evaporate as well, so we don't get the cooling effect that we think," Hermann said. "(The intake) is going to increase with physical activity and heat — especially if you're out doing physical activity in the heat."

She said people need to be aware of how much time they're spending in the heat doing yard work or gardening, going on vacation, running errands or even celebrating the Fourth of July. It's a good idea to drink water before, during and after any activity.

"One little tip is to weigh yourself before and after (an activity)," Hermann said. "You need about two cups of water for every pound loss."

She said taking a "water break" every hour with the family is another helpful tip when everyone is outside. She also suggests wearing light-colored, loose-fitting clothing, drinking beverages that replenish electrolytes (if someone is outside more than an hour) and resting in the shade when tired.

"If you experience any symptoms of heat stroke, stop your activity, ask for help and cool down as quickly as possible," Hermann said.

Older adults are at risk in extreme heat conditions because of multiple physiological reasons, including less water retention due to less lean muscle, a thirst mechanism malfunction, kidney function decline and medications that increase fluid loss. Often, they don't contribute fatigue and weakness to its root cause — a lack of water intake.

Children are at risk because they can easily get distracted playing and forget to consume water.

People who drink caffeinated beverages do lose slightly more fluids, but the losses are relatively insignificant, Hermann said. The recommendation is to drink no more than 400 milligrams of caffeine — or four 8-ounce cups of coffee — per day.

Consuming alcohol decreases a hormone that helps with water retention, so she suggests limiting intake.