Health and Fitness Center
Humans can survive for extended periods of time without many vitamins or minerals, but we can only survive for a few short days without water, as every cell in the human body needs water.
Water makes up about 74 percent of our brain and muscles, and bone is made up of more than 20 percent water. In all, water accounts for 50-65 percent of a body’s entire composition. This amount varies as fat tissue holds less water than lean tissue, so men proportionately have more water per pound than women, since men normally have less body fat.
Water plays an extremely important role in maintaining body temperature. Bodies are cooled through water loss, known as perspiration. Without adequate hydration, this perspiration process is hindered and can result in an overheated body.
Thirst is generally a good indicator that the body needs more water. When the sodium levels of the blood rise, receptors in the brain trigger the thirst sensation. Dry mouth is caused by blood drawing water from the salivary glands.
Also, when the body needs water, our kidneys will excrete less urine. Urine should be a very light yellow color. When urine is a dark yellow color, the body needs more water.
Adults are advised to drink six to eight glasses of water every day. However, adults who eat a high-salt diet or high-protein diet, who live in a hot climate like Hawaii, or who exercise and sweat regularly should increase water intake in order to maintain their electrolyte balance.
Water also performs many other jobs in the body. These jobs include carrying essential nutrients and oxygen to all body parts, removing metabolic waste through urine and sweat, surrounding and protecting a fetus, and serving as a medium for the body’s internal chemical reactions.
Water is the best choice for hydration since it has zero calories. Liquids such as coffee, tea and alcohol not only contain calories but are also diuretics. Diuretics actually increase the loss of body water through the kidneys. So, instead of drinking that second cup of coffee in the morning, grab a reusable water bottle and start tracking water intake.
Water is not only helpful for daily body processes, it’s mandatory.
(Editor’s Note: Information was compiled from “The Tufts University Guide to Total Nutrition.”)