Many of us have heard that our body is made up of two-thirds water, that we should drink eight glasses of water a day, and that by the time we’re thirsty, we’re already dehydrated. While the first statement is true, a lot of what we believe to be common knowledge about dehydration is actually myth.
The daily water intake required varies from person to person. It depends on one’s size, diet, and lifestyle. According to M.D. Heinz Valtin, in order to figure out your requirement you should weigh yourself several days in a row at the same time to determine whether your weight stays fairly constant. If there is a difference of one pound between one day and the next, your water intake the day before was insufficient. Drink a pint of juice or water every morning and continue the experiment to see what fluid intake maintains your weight, keeping the same diet patterns. On average, eight glasses of water or two litres equals the amount the average adult loses through respiration, sweat, and urination. Food and other beverages also count towards replenishing these two litres. In terms of lifestyle, physical activity will affect an individual’s water requirement. R.D. Leslie Bonci, director of sports nutrition in the Medical Center at the University of Pittsburgh explains, “Exercise blunts your thirst mechanism. You lose fluid so rapidly that the brain can’t respond in time.” It’s recommended that people hydrate themselves prior to going to the gym. Bonci says, “It takes 60 minutes for liquid to travel from your gut to your muscles.” In terms of exercise, humans lose salts via sweat, so sports drinks like Gatorade are a wiser alternative.
While thirst is a sign that we are mildly dehydrated, the thirstier we become is not an indication that we are becoming increasingly dehydrated. Also, thirst is not immediately relieved even once we’ve replenished our systems. Studies indicate that by the time we are thirsty, we are two to three per cent dehydrated, but we can satiate this thirst by drinking one per cent of our body’s weight in fluid. For the most part, thirst is a pretty reliable indication of hydration status, and if ignored can result in dire consequences.
Contrary to popular belief, caffeinated beverages are not dehydrating. Research has indicated that the diuretic effects of coffee and tea are negligible, and that caffeinated drinks will hydrate you—just not as efficiently as decaffeinated alternatives. Drinking one cup of coffee will give you two-thirds the equivalent of one cup of water. Lawrence Armstrong, professor of kinesiology at the University of Connecticut says, “Caffeinated beverages do not dehydrate you when consumed in moderation, that is, five cups of less per day of coffee, tea, or cola. Any fluids you ingest will help keep your cells saturated, including juice, iced tea, or soda.”
Unlike other beverages, drinking a lot of water, within limits, won’t cause any harm. In fact, it can help prevent kidney stones in people who are susceptible, ease constipation, aid weight loss, and also alleviate water retention in addition to the multitude of the other roles it plays in sustaining human life.
