Water is an important but often ignored nutrient, and the amount you should drink in a day depends on a variety of factors. Your body needs water for digestion, blood and maintaining the proper biochemical environment for bodily functions. The age-old adage of drinking eight glasses of water a day may not be right for you. Your metabolism, health, physical activity and the temperature of your environment can affect the amount of water you need to stay hydrated. You don't need bottled water specifically unless your drinking water is unsafe.
A general guideline for daily water consumption for healthy adults is approximately 3.7 liters -- around 15 cups -- for men and 2.7L, or around 11 cups for women, according to The Center for Human Nutrition of the University of Nebraska. Note that this recommendation includes any beverages, not just water Thirst is not a good indication of when you need to drink water. By the time you feel thirsty, you could be headed for dehydration. If you're under a doctor’s care or are taking daily medication, ask your doctor for specific guidelines for fluid intake. Certain medical conditions, such as kidney disease, or medications, such as diuretics, can affect your need for water.
Factors Affecting Water Requirements
Many factors can affect the amount of water your body needs each day. If you live or work in a hot or dry environment, you may lose more water through sweat. The more skin is exposed in these environments, the faster hot, dry air will cause body water loss. If you have a fast metabolism or lead a highly active lifestyle, you will require more water daily. Additionally, the more you weigh, the more water you need to drink. Focus on replacing the water you lose per day. Adjust the recommended intake upward if you have higher-than-normal fluid loss.
Dehydration occurs when your body doesn’t have enough water to function properly. You can become dehydrated if you don’t drink enough water, especially if you are losing an increased amount due to activity level or environment. Increased water loss can be due to excessive sweating, urination, diarrhea or vomiting. Dehydration can cause weakness, fatigue, muscle cramps, decreased urine output and confusion. Severe dehydration requires emergency medical attention.
Water in Your Body
At rest, nearly half of the energy your body expends is used to control the level of water and minerals throughout your body. The proper amount of water is required for the biochemical reactions that drive your life. You need plenty of water for your blood to carry nutrients throughout your body and to remove waste. Your body loses a minimum of 1.6 liters, or about 54 ounces, of water daily, according to anesthesiologist Kerry Brandis. Water is lost not only in urine but also through respiration and through the skin. A small amount is also lost in stool; if you have diarrhea, the amount of fluid lost can rise dramatically.