GOT WATER?

The following is a simplified version of the “Self-Testing Program” designed by Douglas J. Casa and printed in the USA Track and Field guidelines. 1 Properly hydrate before your exercise session. Your urine should be clear. 2 Warm up to the point where perspiration is generated. Urinate if possible or needed. 3 Weigh yourself naked on an accurate scale. (e.g.: 150 lbs) 4 Walk for one hour at an intensity similar to your target pace. 5 Keep track of exactly how much fluid you drink during the walk. (e.g.: 10 ounces) 6 Do not urinate during your one-hour walk. 7 Weigh yourself naked again, on the same scale. (e.g.: 149.5 lbs) 8 Subtract your first weight from your second. (e.g.: 150 – 149.5 = .5 lbs) 9 Multiply the difference in weight by 16 (16 ounces = 1 lb.). (e.g.: .5 X 16 = 8) 10 To this number, add the fluid ounces that you drank during the walk. This is the amount of fluid you should drink per each hour you walk (e.g.: 8 + 10 = 18 ounces)

Hydration for walkers

By J.R. Malpass, M.Ed.

Walkers come in all shapes, sizes, and speeds. But all walkers, whether they are strollers, fitness walkers, hikers, racewalkers, or speed walkers, share the need to hydrate properly. Becoming dehydrated during a walk of an hour or more can cause sickness and injury, but so can drinking too much. In fact, the need to drink while exercising has been stressed to the point where many athletes are now over-hydrating and running into serious problems with hyponatremia, especially in events lasting over four hours.

Because of this over-hydration trend, USA Track and Field (USATF) published new guidelines regarding fluid replacement for long-distance runners and launched a new initiative to educate the distance-running public about how to hydrate properly. Although walkers are not specifically mentioned in these new guidelines, the information is applicable. It is important especially to those who engage in exercise sessions longer than four hours. The new guidelines state that, “For athletes in general, and especially for those completing a marathon in more than four hours, USATF recommends consuming 100 percent of the fluids lost due to sweat while racing.”

There is no simple answer for the question of which fluids you should drink, nor how much or how often. Due to individual differences, one has to experiment to find what is best through a self-test. (See sidebar.)

The results of the self-test should be an accurate indication of your fluid replacement needs for one hour under similar pace and climate conditions. If one-half pound is lost during a one-hour walk, during which the walker drinks 10 ounces of fluid, the walker’s total fluid-replacement needs equal 18 fluid oz. (1/2 lb. = 8oz + 10oz = 18 total oz)

To ensure proper fluid replacement during a longer session (especially a marathon), one would want to drink 18 ounces of fluids per hour. Since an average sip of water equals one fluid ounce, four to five sips of fluid every 15 minutes would suffice to fulfill the fluid replacement needs of this individual.

A person’s ability to drink fluid while exercising, and to dissipate heat from his or her core temperature, has a number of variables, including:

Sweat rate: Some people sweat quickly and copiously, while others show little fluid loss. In addition, the size of the person (larger people sweat more than smaller people), the intensity of effort (higher intensity/speed equals more sweat), and temperature and humidity (temperature over 60 degrees F, and humidity over 60%) can adversely affect sweating.

Rate of gastric emptying: Stomachs absorb fluids differently. World-class athletes are able to drink and absorb copious amounts of fluid each hour, while other (perhaps less genetically gifted) athletes may become sick attempting to drink a similar amount.

Type of fluid drink: Sport drinks must contain 8% or less of carbohydrate to be absorbed properly. High sugar content or simple sugars in fluids can slow absorption. Carbonated drinks can cause stomach distress. Caffeine and alcohol are diuretics, i.e., they cause fluid loss.

Percentage of body fat: Fat acts as an insulator, holding in core heat and forcing the thermo-regulatory system to work harder.

Heat acclimatization: Ten days to three weeks of exercise in the heat is needed to fully acclimatize for optimum performance. As this happens, the sweat becomes more diluted (i.e., less minerals are lost) and the threshold at which sweating begins is lowered.

Medications: Certain drugs may cause dehydration or interfere with sweating. Antihistamines and some blood-pressure medications decrease sweating. Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil, Motrin) and naproxen sodium (Aleve) may be harmful to kidney function if taken within 24 hours of strenuous exercise. These NSAIDs are thought to increase the possibility of hyponatremia while running or walking long distances. Acetaminophen, marketed as Tylenol, has been shown to be safe.

Most common reasons for not drinking
1 “It upsets my stomach” Drinking must be practiced. Carry water with you, and drink smaller amounts more frequently. Avoid swallowing air or gulping. Slow your pace while drinking. Sport drinks need to be 8% (or less) carbohydrate solution to be properly absorbed in the stomach. What is eaten or drunk prior to an exercise session (even the evening before) may affect how fluids are absorbed.
2 “I have to stop and urinate too often if I drink while walking” Plan your walks with convenient restroom stops. Avoid diuretics (coffee or alcohol) prior to walking. Do not “over-hydrate” (forcing fluids) prior to walking. Have your last drink 20 to 30 minutes prior to beginning your walk. Timing is important: if fluid is consumed longer than 30 minutes prior to exercise, it causes diuresis (excessive urination) at the onset of exercise.
3 “I don’t like the taste” Experiment with various sport drinks or try adding a squeeze of lemon to your water bottle. Some electrolyte replacement powders can be mixed with water to provide taste, which may enhance drinking and provide needed minerals lost through sweat.

Practice makes perfect
Self-testing to determine your individual fluid needs is extremely important and should be incorporated into your training if you regularly walk an hour or more. Practice drinking while on walks to determine the type of fluids your body will best tolerate during your walking session. Self-test once every few months to stay on top of changing seasonal temperatures and your own body’s adaptations. After a few weeks of practice, hydrating properly will become second nature.

J.R. Malpass worked as chief of kinesiotherapy in the Rehabilitation Medicine Service of the Portland Veteran Affairs Medical Center and instructed at the School of Health and Physical Education at Portland State University. Currently a head coach for the Portland Fit marathon training program, Malpass has run over 30 marathons, one ultramarathon, and has completed two Ironman competitions.