JULY 2003

A Through perspiration, a person can lose about two quarts of water an hour. That's a significant amount of fluid. To replace that loss, you need to drink about a glass of water every 10 to 20 minutes.

Studies have shown that drinking to satisfy thirst only replenishes two-thirds of the amount of water a person should drink when working or playing in the Arizona sun.

So thirst is not a good indicator that you need to drink water. By the time you feel thirsty, you're already well on your way to dehydration.

A better indicator of hydration is urine output. If you urinate your normal amount and frequency, the body is well-hydrated, provided you don't have kidney disease. If you urinate small amounts of dark-colored urine, you need to drink more water until the urine is consistently pale-colored.

Other signs of water depletion include dry lips and tongue, dry-looking skin that has lost its elasticity, increased heart rate and breathing, dizziness and confusion. Signs of salt depletion as well include lethargy, headache, cramps and pallor.

In general, plain water is better than other fluids. Drinks containing caffeine or alcohol, which are natural diuretics, cause more fluid loss by increasing the amount of water lost in the urine.

Sweat contains far more water than electrolytes, which many sports drinks contain. But if you lose a lot of sweat for hours then you'll need to replace the electrolytes as well.

Remember, the primary issue is hydration, so start drinking before you feel thirsty.

—Harvey Meislin, MD, director, Arizona Emergency Medicine Research Center, Arizona Health Sciences Center, Tucson

Q I'm having trouble remembering things, but tests have ruled out Alzheimer's and dementia. What should I do?

A Most of the time, memory difficulties are due to stress, anxiety and having our circuits "overloaded."

Problems remembering names and events from long ago (long-term memory loss) are more indicative of this overload phenomenon. Short-term memory loss is characteristic of Alzheimer's disease and other forms of dementia.

Here are some tips for maintaining a healthy memory throughout your life:

• Lifelong learning. Keep an active mental life with reading, puzzles, volunteer activities and other interests — "use it or lose it."

• Exercise. Regular physical activity increases blood supply to the brain and has been shown to increase test scores in many cognitive areas.

• Daily activities. Participate in social activities and follow a daily schedule, especially after retirement.

• Stress reduction. Stress is a major cause of poor concentration. Take up some form of daily stress reduction for 20 minutes once or twice a day, such as meditation, prayer, deep breathing or yoga. Tai chi or chi gong help relieve stress while serving as daily physical activity.

• Sleep. Try to get at least 8 hours of sleep every night. If you can't, consider a 20-minute nap from 1 to 2 p.m. in the afternoons, which equals about an hour of nighttime sleep.

• Emotional stability. We know from the Alzheimer's study of nuns by David Snowdon, PhD, (author of Aging with Grace) that depression contributes to significant memory loss. Emotions like fear, anger, loneliness and confusion also lead to memory changes, while love, happiness, gratitude, contentment and altruism help sustain long-term and short-term cognitive vitality.

• Nutrition. Dementia is an inflammatory process, so eat anti-inflammatory foods rich in ginger and curry, for instance. Eat a balanced diet with lots of antioxidants (5 to 10 servings of fruits and vegetables a day) and rich in folic acid and the B vitamins to protect against stroke.

—Evan Kligman, MD, co-director, Arizona Center on Aging, Arizona Health Sciences Center, Tucson

Editors Note: ASK AHSC is published by the AHSC Office of Public Affairs. Reporters may quote from ASK AHSC; we request that credit be given. ASK AHSC is available on the Internet at www.ahsc.arizona.edu/opa/answers. To receive ASK AHSC via E-mail, call (520) 626-7301. Health questions should be sent to: ASK AHSC, AHSC Office

of Public Affairs, PO Box 245095, Tucson, AZ 85724-5095, or E-mail to: jspinell@u.arizona.edu. The information here is not intended to replace the advice of your physician. For referral to a UA physician, please call University Health Connection, (520) 694-8888.

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