There are a number of opinions on this subject, though some medical personnel believe they have established a recommended, necessary amount of water that is correct for human beings. In fact, authorities from across the medical spectrum provide different answers, with several qualifications.
For example, the revered Mayo Clinic staff emphasizes that there are no simple answers to what seems to be a simple question.The Mayo Web site even states, “…your water needs depend on many factors, including your health, how active you are and where you live.”
Since water makes up most of the human body (about 60 percent in some estimates) it is essential that human beings drink enough fluids to keep the body in a health, hydrated state. Water used in various processes by the body will help cleanse the body of toxic substances and is the primary way that nutrients get to the various parts of the body.
But how much water is right to maintain good health? According to most medical literature, the average human adult puts out a bit more than a liter or more of urine each day. An equal amount may be lost from the body each day by normal breathing and sweating. A person may want to use this measure to determine how much water is needed to replace the amounts lost by the above-mentioned processes. This means a person should probably be taking in about two liters of water each day along with a normal diet that provides some of the necessary fluids. This is where the “eight cups per day” recommendation comes from.
For several years now, people have recommended drinking eight glasses of water each day, at 8 ounces each. This amounts to just a bit under two liters, which is close to the replacement method already mentioned. There really isn’t a lot of solid scientific research to support this but it may be a good guideline for the normally healthy person.
Some medical authorities advise considerably more than this two-liter recommendation, with some advice stating three liters is the necessary amount. This can vary depending on the diet of the individual, overall health and any special requirements due to health, job stress, weather conditions etc. Doctors often go by the general guideline that states: if a person drinks enough water to keep from feeling thirsty and the urine has no color or only a slightly yellow color, the amount of water is about right.
When trying to determine how much water a person should drink each day, individuals should consider several factors. These include: how much exercise does the individual engage in daily; what sort of weather/environment does a person live and work in; are there any health issues that might change the amount of water needed?
While it isn’t good to simply rely on how thirsty you feel to determine if you need to drink more water, this is a good general guideline. Many people who don’t “feel” thirsty are already a bit dehydrated. A couple of good habits would be: drink a glass of water with each meal; drink some extra water before exercise, during exercise and after an exercise session.