A Cool Drink of Water: Hydration Advice from a Memorial Dietitian

When temperatures soar, we’re often reminded to drink more fluids. So how much is enough? And what happens when you get too much?

Eight cups of water daily. Most of us have heard that’s how much water we should drink. But that’s just an average that’s easy to remember. To calculate your specific needs, divide your weight in pounds by 17. That’s the number of cups of water right for your body on an average day.

Hydration is important because 60 percent or more of our bodies are made of water. Every system in the body depends on water to function. It is necessary for metabolizing food, passing waste and regulating blood pressure, according to Jennifer DiPasquale, RD, CDE, lead dietitian at Abraham Lincoln Memorial Hospital.

Dehydration occurs when we don’t consume enough water. Symptoms include dry skin and mouth, decreased sweating and urination, headache, and light headedness. Strangely enough, thirst is not a reliable indicator of fluid needs, especially in extreme heat conditions, according to DiPasquale.

In extreme heat conditions, we can lose from 3 to 8 cups of fluids through perspiration per hour! Sweating helps our body lower its temperature, and decreased perspiration is a danger sign indicating the need for immediate treatment with fluids and removal from heat.

The reverse of dehydration is hyperhydration, often called water intoxication, which results when the normal balance of electrolytes in the body is dangerously altered by excess water consumption.

Most of us don’t have to worry about hyperhydration. Deaths usually occur following unusual circumstances such as water drinking contests or extremely long and intense stretches of exercise during which an excessive amount of water is consumed but electrolytes are not properly replenished.

Symptoms of hyperhydration include headache, behavior and personality changes, drowsiness, muscle weakness and twitching, nausea, cramping, difficulty breathing during exertion, thirst, and colorless and/or excess urination.

Advice from the expert:

• If you work in extreme heat conditions or choose to exercise in them, replace lost fluids. This is especially important for children and teens participating in sports or attending practices.
• Weigh before and after work day or activity. Replace each pound of body weight lost with 3 cups of fluid.
• Drink 1½ to 2 ½ cups 2 to 3 hours before beginning your workout or event.
• Consume ½ to 1 ½ cups every 15 minutes for events lasting longer than 30 minutes.
• Half of the replacement fluid should be a sport drink (something with sodium and electrolytes) and half water.