This is also true for the human body. In fact, 60 percent of the weight of the average adult is water.
Every cell of the body contains water. Water is also part of the fluid between cells and in the bloodstream.
The body needs water on a daily basis and can survive only for a few days without it.
Because water is so crucial to the body, I often describe water as the most important nutrient. Water lubricates the joints, cushions body organs, carries nutrients and waste products throughout the body, serves as a solvent, regulates body temperature and maintains blood volume.
Water is needed for many of the chemical reactions happening in metabolism.
When the body has lost too much water and it is not replaced, dehydration occurs.
Early signs of dehydration are fatigue, weakness and dry mouth.
Dehydration can decrease your mental and physical performance.
Thirst is the body’s conscious dehydration signal, reminding us to seek fluids.
Unfortunately, a person could be 1 percent to 2 percent dehydrated before the body’s thirst response kicks in.
The daily amount of water a person needs depends on factors such as age, weight, gender, activity level, overall health and intake of medications or dietary supplements.
Other factors play a role, too, such as air temperature, humidity, and even, altitude.
The Institute of Medicine has determined that an adequate intake for men is roughly 13 cups (3 liters) of total beverages a day. The adequate intake for women is about 9 cups (2.2 liters) of total beverages a day. Depending on age, school-aged children need 6 to 11 cups of water a day. Physical activity increases needs for all groups.
For many people, tap water is their main source.
Public water systems treat water to remove contaminants and are regulated by the U.S. Environmental Protection Agency. Some households use home water treatment to further remove chlorine, heavy metals, minerals or potential microorganisms.
Water is also available in stores in many forms, bottled from municipal water supplies or natural sources. Some water has been treated by filtration or distillation to remove minerals or contaminants. Bottled waters can be “enhanced” with sweeteners, juices, colors, flavors, vitamins, minerals, protein, or extra oxygen. Bottled water can also be sparkling, as in seltzers or tonic water.
Drinking water is not the body’s only source of water.
Some of the metabolic reactions of the body generate water.
Other beverages we drink, and most foods, also contain water. Notable for contributing the most water from foods are fruits and vegetables.
All beverages contribute to daily water intake.
Nutrient packed options are milk and 100 percent fruit juice. Unsweetened coffee and tea are calorie-free options.
Despite the controversy, caffeinated beverages are not strong diuretics (causing increased urination).
Less healthy choices for replacing fluids are sugar-sweetened beverages, as these are likely to lead to weight gain.
Alcoholic beverages are poor choices due to their diuretic effect combined with impairment of a person’s health when consumed in excess.
Physical exertion, especially when combined with hot temperatures, increases water losses from sweating and respiration. Thus, exercising in the summer makes a person more vulnerable to dehydration. Fortunately, New Mexico’s generally low humidity allows a sweating body to cool more efficiently, even though sweating still contributes to water losses.
Endurance athletes whose workouts last more than an hour perform best when sticking to a hydration plan. Such a plan for a male athlete might be: 4 hours before the activity, drink 2 cups of water; 2 hours before, drink another cup; drink ½ cup or more every 15 minutes during the activity; and drink 2 cups of fluid every 20 minutes until rehydrated. Activities with heavy sweating that last more than an hour generally require a sports drink solution, containing electrolyte minerals such as potassium and sodium. Strenuous activities performed for longer periods may require solutions containing simple sugars in order to maintain performance.
When I discuss the importance of staying hydrated with my clients, many are already convinced that water is important. But, not all people are able to meet their water needs. I find that people who do the best at staying hydrated have made a conscious commitment to drinking fluids during the day despite busy lifestyles and distractions.
Sara Perovich is a registered dietitian nutritionist working as a clinical dietitian in Albuquerque. She’s a member of the New Mexico Academy of Nutrition and Dietetics.