How your fluid needs are calculated
There’s no universal number like “two litres for everyone”: needs depend on body weight, activity, air temperature and your diet. A practical guideline is 30 ml per kilogram of body weight per day.
Intake = weight × 30 ml × activity factor × weather factor
For 63 kg with medium activity in mild weather: 63 × 30 × 1.1 × 1.05 ≈ 2,180 ml.What counts towards it
All fluids count, not just plain water: tea, coffee, fruit drinks, soup, kefir, and the water in vegetables and fruit. Coffee and tea don’t “dehydrate” you - their diuretic effect is minor and fully offset by the volume you drink.
- water, mineral water, tea, coffee - count in full;
- soup, broth, kefir, milk - count as fluid;
- vegetables and fruit add another 20–30% of the daily volume;
- sugary drinks count as fluid, but go into added sugar in the Score.
When you need more water
| Situation | Add |
|---|---|
| 60-minute workout | +500–700 ml |
| Heat above 27°C | +10–15% |
| High altitude | +500 ml |
| Fever, food poisoning | as advised by a doctor |
Signs you’re not drinking enough
The simplest guide is urine colour: pale yellow is normal, deep dark yellow means you’re short. Other signs are an evening headache, dry mouth and lower endurance during training. Thirst is a late signal, so it’s easier to drink on a schedule: a glass after waking up and one with each meal.