Eight Glasses Of Water Per Day Myth

Water is essential to life and human bodily function. But how much should we drink? A common suggestion is to drink eight glasses a day. Heinz Valtin MD, a professor of physiology at Dartmouth, doubts the recommendation's validity. He reasons that it is hard to believe that evolution left humans with a chronic water deficit. Still, authorities like the U.S. National Library of Medicine state that if adequate water is not consumed on a daily basis, body fluids will be out of balance, causing dehydration, which if severe can be life-threatening. Water needs depend on many factors, including a person's health, activity level and geographic location.

Significance

Water is important to many bodily functions. The Mayo Clinic states that water is used by the body to regulate body temperature, lubricate joints, moisten tissues, protect organs, prevent constipation, aid in the excretion of waste products, carry nutrients and oxygen to cells, and help dissolve nutrients. Water is lost through breath, perspiration, urine and bowel movements. For the body to function properly, the water must be replenished its by consuming beverages and foods that contain water.

Considerations

Because water is lost each day, many doctors and nutrition consultants advise a person to drink eight or more glasses of water a day. According to a 2002 article by Valtin in the "American Journal of Physiology Regulatory Integrative and Comparative Physiology," despite the seemingly ubiquitous admonition to "drink at least eight 8-oz. glasses of water a day," rigorous proof for this counsel appears to be lacking. The article states that under special circumstances, such as vigorous work and exercise, especially in hot climates, this amount of water is needed.

Types of Replenishment

Without evidence to prove one hydration strategy over another, several have been created. According to the Mayo Clinic, three main strategies are generally used. They are the eight-glass-a-day rule, the replenishment approach and those based on dietary recommendations by The Institute of Medicine. The Mayo Clinic website states that the eight-a-day rule is not supported by scientific evidence, but it is commonly used as an easy-to-remember guideline.

Benefits

According to the U.S. National Library of Medicine, all cells need water and water serves as a lubricant, is the basis of saliva and the fluids surrounding the joints, and regulates the body temperature through perspiration. The U.S. National Library of Medicine states that water also helps prevent and alleviate constipation by moving food through the intestinal tract. Therefore, drinking water each day provides benefits to the body and helps it function optimally.

Expert Insight

Drinking eight glasses of water a day appears to be more of a guideline than an actual requirement. The lack of evidence does not make the recommendation a bad idea; it simply does not prove that is is absolutely correct. Drinking water is good for the body and helps it function correctly, so it is important to drink enough water to replenish the fluids lost throughout the day.