Water is life and the human body, which is made up of between 55 and 75 percent water, is in need of constant water replenishment.
Your lungs expel between two and four cups of water each day through normal breathing - even more on a cold day. If your feet sweat, there goes another cup of water.
If you make half a dozen trips to the bathroom during the day, that’s six cups of water. If you perspire, you expel about two cups of water (which doesn’t include exercise-induced perspiration).
A person would have to lose 10 percent of her body weight in fluids to be considered dehydrated, but as little as two percent can affect athletic performance, cause tiredness and dull critical thinking abilities.
Adequate water consumption can help lessen the chance of kidney stones, keep joints lubricated, prevent and lessen the severity of colds and flu and help prevent constipation.
Health benefits of water
Water is crucial to your health. It makes up, on average, 60 percent of your body weight. Every system in your body depends on water.
Lack of water can lead to dehydration, a condition that occurs when you don’t have enough water in your body to carry on normal functions. Even mild dehydration - as little as a 1 percent to 2 percent loss of your body weight - can sap your energy and make you tired.
Dehydration poses a particular health risk for the very young and the very old. Signs and symptoms of dehydration include: Excessive thirst, Fatigue, Headache, Dry mouth, little or no urination, Muscle weakness, Dizziness and Lightheadedness.
Every day you lose water through sweating - noticeable and unnoticeable - exhaling, urinating and bowel movements. For your body to function properly, you need to replace this water by consuming beverages and foods that contain water. So how much water, or more precisely fluid, do you need? Eight glasses of water a day is what is recommended.
Factors that influence water needs
You may need to modify total fluid intake from these recommended amounts depending on several factors, including how active you are, the climate, your health status, and if you’re pregnant or breast-feeding.
• Exercise. If you exercise or engage in any activity that makes you sweat, you’ll need to drink extra water to compensate for that fluid loss. Drink 2 cups of water two hours before a long endurance event, for example, a marathon or half-marathon. One to 2 cups of water is also adequate for shorter bouts of exercise. During the activity, replenish fluids at regular intervals, and continue drinking water or other fluids after you’re finished. During intense exercise involving significant sweating, for example, during a marathon, sodium is lost in sweat, and you may need a sports drink with sodium rather than just water.
• Environment. You need to drink additional water in hot or humid weather to help lower your body temperature and to replace what you lose through sweating. You may also need extra water in cold weather if you sweat while wearing insulated clothing. Heated, indoor air can cause your skin to lose moisture, increasing your daily fluid requirements. And altitudes greater than 2,500 meters (8,200 feet) also can affect how much water your body needs. Higher altitudes may trigger increased urination and more rapid breathing, which uses up more of your fluid reserves.
• Illnesses or health conditions. Some signs and symptoms of illnesses, such as fever, vomiting and diarrhea, cause your body to lose extra fluids. To replace lost fluids, drink more water or oral rehydration solutions. When water loss can’t be replaced orally, intravenous water and electrolytes may be necessary. Increased water intake is nearly always advised in people with urinary tract stones. On the other hand, you may need to limit the amount of water you drink if you have certain conditions that impair excretion of water - such as heart failure and some types of kidney, liver, adrenal and thyroid diseases.
• Pregnant or breast-feeding. Women who are pregnant or breast-feeding need additional water to stay hydrated and to replenish the fluids lost, especially when nursing. It is recommended that pregnant women drink 2.3 liters (nearly 10 cups) of fluids a day and women who breast-feed consume 3.1 liters (about 13 cups) of fluids a day.
If you drink water from a bottle, thoroughly clean or replace the bottle often. Every time you drink, bacteria from your mouth contaminate water in the bottle. If you use a bottle repeatedly, make sure that the bottle is designed for reuse. To keep it clean, wash your container in hot, soapy water before refilling it.