Brought to you by:
Sutter Medical Center, Santa Rosa
How many times a day do you see someone carrying around a bottle of water? Maybe you have a bottle of water with you right now. But how much water do we really need? Is it eight cups a day like you’ve always been told?
The DRI (Dietary Reference Intakes) for total water is 2.7 liters (90 ounces) per day for adult women and 3.7 liters (123 ounces) per day for adult men. But total water comes from a combination of water, beverages and food. Typically 20% of your fluid intake would come from food; therefore women need to drink 2.2 liters or a little over 9 cups of water and other beverages each day and men need 12 1/3 cups per day.
However, there are many different formulas for calculating fluid needs. For those of you that want to do the math, here are some of the more common ones:
1ml fluid per calorie consumed
30ml fluid per kg of weight
100ml/kg for the first 10 kg of weight, plus 50ml/kg for the next 10 kg, and 15ml/kg for the remaining weight.
If this all sounds a little confusing, here are some facts. We know water is crucial to your health; every system in your body depends on water to function. It helps regulate the body’s temperature, forms the basis for all body fluids, and is involved in the transportation and absorption of nutrients and elimination of waste. Water makes up, on average, 60% of your body weight and each day you need to replace the water lost through breathing, sweating and eliminating waste. But there are other factors that may also affect your water needs:
Exercise – if you’re active enough to sweat, you’ll need to replace that fluid. The longer you exercise the more fluid you’ll need. Larger athletes sweat more and well-trained athletes sweat more because they are conditioned to be able to efficiently cool their bodies through perspiration. During vigorous exercise it is important to drink before you get thirsty.
Environment – hot or humid weather causes increased sweating and water also helps lower body temperature. Being at a high altitude (defined as over 8000 feet) often causes rapid breathing and increased urination as your body tries to adjust to the higher altitude.
Illness or chronic health conditions – fever, vomiting and diarrhea can cause your body to lose extra fluids. Uncontrolled diabetes can increase urination, as can many medications.
Pregnancy or breast-feeding – women need additional water to stay hydrated and to replenish lost fluids, especially when nursing.
Generally, if you drink enough water to quench your thirst, feel well and produce colorless or light yellow urine, your fluid intake is adequate. But what happens if you don’t maintain your body’s fluid balance? You become dehydrated. Dehydration impairs concentration and coordination, reduces stamina and impairs the body’s ability to cool itself.
Infants and children are at greater risk for dehydration because of their smaller body weights; the elderly are also at risk because they are less able to sense thirst. If untreated, dehydration can lead to serious consequences such as heat exhaustion, seizures, kidney failure, coma and death.
The signs and symptoms of dehydration include:
Little or no urination
Healthy adults can usually treat mild to moderate dehydration by drinking more fluids. Drinking small amounts of fluid frequently is often more effective than trying to drink large amounts at one time. For infants and children, you can use an oral rehydration solution (such as Pedialyte). These solutions contain water and salts in specific proportions to replenish both fluids and electrolytes. They also contain carbohydrate to enhance absorption in the intestinal tract. Avoid using just water to rehydrate infants and children. Severe dehydration should be treated by medical personnel, usually with IV fluids.
To prevent dehydration, drink plenty of fluids throughout the day; you can use any of the methods discussed earlier to determine how much you need. Don’t forget that foods contribute to your fluid intake too. Anticipating the potential for dehydration and increasing fluid intake is important. Although all fluids contribute to your total water intake, beware of sweetened beverages such as sodas, flavored teas and nutrient enhanced drinks – they can contribute significant calories your diet. Water is your best choice - it’s calorie free, inexpensive and readily available.