Water: nine glasses and why the kidneys care
The dullest health advice in existence, and one of the few that is almost universally under-followed.
This is the dullest piece of health advice in circulation, and one of the few that nearly everybody is genuinely short on.
What water is doing
The kidneys filter the blood continuously, and they need water to carry away what they remove. Short of water, they concentrate the urine, work harder, and - in people prone to them - make kidney stones considerably more likely.
Water also carries nutrients, regulates temperature, cushions joints, and is the medium every digestive enzyme works in. Mild dehydration shows up as tiredness, headache and poor concentration long before it registers as thirst.
How much
Eight to nine glasses a day suits most adults in an Indian climate. More in summer, more if you work outdoors or exercise, more if you drink a lot of tea or coffee.
Pale straw-coloured urine means you are about right. Dark yellow means drink more. This is a better guide than counting glasses, and it is free.
A caveat worth stating
People with kidney disease or heart failure are sometimes on a deliberate fluid restriction. If a doctor has given you a limit, that limit is correct and this article is not. General advice does not override a prescription written for you.
