How Much Water Should You Drink a Day
There is no single magic number for water. Your needs shift with heat, exercise, and body size. Here is how to find a target that fits you.
Water keeps your temperature steady, moves nutrients, cushions joints, and helps your kidneys clear waste. But the popular eight glasses rule is more slogan than science. Your real need depends on your body size, how active you are, and the climate you live in. The goal is steady hydration, not hitting one fixed number.
A sensible baseline
Health bodies usually suggest a total fluid intake in the range of about 2 to 2.5 litres per day for adults, and that total includes water from food. Fruit, vegetables, soups, and most drinks all count. Use this as a starting range and adjust it based on how you feel and what your body signals.
What raises your needs
Several things push your water needs higher. Hot or humid weather makes you sweat more. Hard exercise can cost a litre or more of fluid per hour. Larger bodies need more, and so do illness with fever, high altitude, and pregnancy or breastfeeding. On those days, drink more than your usual baseline.
- Hot, humid weather and heavy sweating.
- Intense or long exercise sessions.
- Fever, vomiting, or diarrhoea.
- Pregnancy and breastfeeding.
How to tell you are hydrated
You do not need to count every millilitre. Pale, straw-coloured urine and rarely feeling very thirsty are good signs you are well hydrated. Dark urine, headaches, and constant thirst suggest you need more. Spread your intake through the day rather than gulping a large amount all at once.