Water is the one of the basic element of life. It’s the mere presence of it on earth makes is habitable, that is why the earth is the only planet in millions of galaxies which has life on it.
According to one of the many theories of “Origin of life” is said to be started in water and there on with years of evolutions has moved to the land.
Most Doctors says on an average about 8 -10 glasses are needed to meet our body’s water requirement. But it could vary based on your various factors like your gender, age, height, weight, climatic conditions, your profession ( If you work in a field and your profession demands hard labor and you sweat a lot in the whole process ) and more. Eg: A man of exact same stats having different lifestyles will have different water needs. Check out this awesome Hydration calculator, based on various factors it gives you an estimate as you how much water intake is needed for your body.
According to a survey by Institute of Medicine approx 11 cups a day for women and 15 cups for men is the guideline for fluid intake, Emphasis is on fluid intake and not water, water melonYour juice, coffee, shakes count toward this, this also includes your watermelon, oranges, grapefruit and so on, you get the picture.
The short answer is, always listen to your body drink when thirsty, eat when hungry and last but not least sleep when tired !! Respect your body and get in tune with it !!