Water - Vital for Life

Two parts hydrogen and one part oxygen, water is the most abundant substance in the human body, accounting for up to 60% of our body weight. Even though water has no calories or other nutrients, we can go for only a few days without it. In contrast, a healthy person can survive for 6 to 8 weeks without food. A loss of only 5 to 10% of body water results in serious dehydration, while a 15 to 20% loss is usually fatal.

Vital Functions

Water is essential to 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. Water is needed to build all 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 organs and joints. It also keeps our skin soft and smooth. As our body ages, it becomes dryer. An infant's body is 75 to 80% water, compared to 50% after age 65 or 70.

How Much Do We Need?

The human body needs enough water to ensure the urine is pale, not dark or bright yellow. For the average adult this translates to 6 to 8 glasses of water a day. Most of this comes from drinks, but surprisingly there is a substantial amount in foods as well. Fruits and vegetables are 70 to 95% water, compared to 75% of an egg, 40 to 60% of meat, poultry, and fish, and 35% of bread.

While trying to lose weight, it is said that you should consume half of your body weight in ounces of water. In my case, at 135 lbs, I should be consuming approximately 68 oz. (2 litres) of water daily.

It is also important to remember that you should consume as much water as you excrete during any given day. So on days where the weather is hotter or you sweat due to a hard workout, you should consume more water.