Almost none of us pay much attention to the amount of fluid we drink--it's just a part of our lives that takes care of itself, right? Wrong. The recommended daily allowance for water proposed by the National Research Council is a quart and a half a day (48 fluid ounces or 1.4 liter). Few of us drink this recommended amount just because we are supposed to. Our wonderful kidneys let us get away with such nonchalance as they carefully regulate the amount of fluid we excrete or retain according to how much we drink. The kidneys filter 150 quarts (4,800 fluid ounces or 142 liters) per day but excrete only 1 percent of this. The urine our kidneys make serves as a transfer vehicle for some of the waste materials of our bodies, particularly the urea which is derived from protein metabolism. But when we get older, our cueing becomes faulted. In other words, when older people are denied fluid for 24 hours, their thirst is blunted. We sometimes drink when we shouldn't, causing dilution of our body minerals, or we don't drink when we should which causes dehydration. Medicines, particularly diuretics, and disease conditions often seen in older people make fluid consumption more than a casual affair. Neglect of symptoms and poor compliance with medications can be very dangerous. Severe constipation can also complicate dehydration.
Water Is Your Friend
Our hunter-gatherer ancestors only had water to drink. Nowadays, however, it seems almost no able-bodied person drinks plain water. Fluid comes in various colors and temperatures, with varying bubbles and other complications. But plain water still claims many advantages. It has no calories, or salt, and it does its job of lubricating us just fine. We are, after all, 60 percent water.
Drink to Beat the Heat
Then there are the external factors. Heat causes increased fluid loss through perspiration, which can, on occasion, be extreme and result in substantial dehydration. Infection, when accompanied by fever, clearly imposes an increased fluid demand, and colds in particular benefit from more fluid intake, as fluids help keep the mucus from getting too sticky and difficult to eliminate. The aging process itself has been shown to disrupt the body's thermoregulatory center, so fluid ingestion when temperatures rise is very important. That's why heat waves are dangerous for older people.
Alternative Fluid Sources
Of course, fluids are not the only source of body water, as your food produces almost as much and your metabolism generates a smaller amount. So, if you don't eat well for any one of a number of reasons, dehydration may result. Your body can stand weeks of calorie loss, but your fluids are at a more immediate risk.
Back to Bedwetting
Another complication seen in older persons that can cause fluid distress is the annoying need to urinate at night, causing disruption in sleep. Many older persons respond by simply not drinking enough. This misadventure is best addressed by making sure you drink enough fluid early in the day, so that the bladder doesn't have to perform so much at night.
Bottom line:
Drink early, drink enough, and never let your urine turn dark due to dehydration.
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