Is drinking extra water harmful to the body?

Q: I was given to understand that the normal intake of water can @ 1.5 litres per day for adults. Is it ill-advised to consume more than 1.5 litres. Say if an individual consumes around 3 to 4 litres a day, will it have an impact in the long run?

A:Water is essential for all bodily functions, and the intake depends on how much you put out. There is insensible loss through perspiration of about 700 ml which you do not even see. You also lose about 300 ml through vapour in the breathing. If you add that to what you lose through urination and defaecation (may amount to over 2 litres), you can see that your 1.5 litres is an underestimate of what you need. In warmer climates such as in India you would lose a lot more through visible perspiration which needs to be replaced. Thus, you may need about 3 litres in an ordinary day and even more if you are active and lose a lot more through perspiration. If you drink in excess of what you need then your kidneys will wash it out if they are normal. In short, if you are an active, healthy individual drinking extra water has no harmful effects.