This seemingly harmless, calorie free, nutrient free, colourless, tasteless liquid happens to be the most important constituent needed to live. We can survive without food, but not without water. Water is second only to oxygen in maintaining life.
Nearly 60 per cent of our body is made up of water and virtually every body function, including digestion, absorption, and transport of nutrients, elimination of body waste, and regulation of body temperature, as well as many other chemical processes, involve water. Water is needed to build body tissues and is the base of all blood and fluid secretions such as tears, saliva, and gastric juices, as well as the fluids that lubricate our joints and organs. It provides a protective cushion for body cells and also keeps our skin soft and smooth.
Insufficient intake of water can significantly decrease work performance, cause constipation, hyperacidity and increase the risk of kidney problems, renal stones and urinary tract infections. Other effects include changes in skin, hair and even appetite.
Our daily needs vary a lot. We need more water in hot weather, during exercise, or when we have fever, cold, or other illness. We also need more during pregnancy to provide for amniotic fluid and the expanded blood volume, as well as to meet the needs of the developing fetus. Nursing mothers need to increase their fluid intake to produce milk (87 per cent water).
Thirst may lag behind the body’s need for water during intense exercise or when it’s extremely hot and humid. By the time you feel thirsty, you may already be dehydrated. How do we know that we are getting enough water? A good indicator is to ensure that the urine is pale and light coloured. Dark or yellow colour indicates you are not consuming enough water or fluids.
About 80 per cent of people’s daily water intake comes from drinking water and beverages, including caffeinated drinks, and 20 per cent comes from water contained in food. For an average adult this may translate to six to eight glasses of water a day. Most of this comes from drinks – plain water, coffee, tea, juices, soft drinks – but surprisingly there’s a substantial amount in foods as well.
As a general rule, the amount of water we consume should be equal to what is excreted. Many factors can affect this balance. For example, taking diuretics or other drugs that increase urination also increases our needs for fluids. Drinking large amounts of tea or coffee has a similar diuretic effect which can offset the fluid intake from these drinks. And eating salty foods also increases our need for extra water to maintain proper fluid balance.
Making up for your water requirements is better achieved by drinking through the day, rather than loading up at one time. Drinking water with the meals is not contra-indicative, rather it may help you eat less. In fact, drinking water with meals may help you lose weight and body fat over time by limiting the amount of food. According to a recent study, increasing water intake causes significant weight loss, independent of caloric intake and exercise. However, sweetened beverages have not been found to have this effect.
As our body ages, it becomes dryer. The body of a newborn infant is 75 – 80 per cent water, compared to 50 per cent after age 65 or 70. This drying out is reflected in the wrinkled skin, reduced saliva flow, and stiffened joints that occur naturally with ageing. Thirst threshold increases with age; therefore, older people need to pay more attention to drinking enough water as they have decreased thirst.
Exercise sweat loss, mainly in the heat, can also cause dehydration, alter the hydro-electrolyte balance, disturb thermoregulation (maintenance of body temperature), and lower athletic performance. It is a good idea to consume 500 mls of fluid about two hours before exercise. During exercise, losses need to be replaced. Beverages consumed during exercise should be cool, palatable, with some sugars and electrolytes (salt).
If you drink more fluid than you need, the kidneys excrete the excess by increasing the volume of urine and excess is absorbed by our cells. Drinking surplus water is harmful for kidney and heart failure patients. Contrary to the popular belief that drinking water causes bloating, exactly the opposite is true. Drinking water will decrease bloating. Salt and sodium rich foods like preserved meats, soups and pickles etc, imbalanced female hormones, cardiac dysfunction, or renal disease are the most common causes of bloating.