Why do we need to drink water?
As water makes up between 50 and 70% of an adult's total body weight, regular top-ups are needed to balance the loss of water from the body in the form of urine and sweat.
If we did not replace the water lost the body would not be able to survive. Dehydration will set in, firstly, with headaches, tiredness and loss of concentration followed, in extreme cases, by constipation and in the long-term kidney stones.
The British Dietetic Association advises that we should consume 2.5 litres a day to remain healthy.