Understanding fluid needs supports performance and health.

Water makes up 50–80% of body weight. Even mild dehydration may impair concentration and performance.
| Group | Total (L/day) | From Beverages |
|---|---|---|
| Men 19–70 | 3.4 | ~2.6 L |
| Women 19–70 | 2.8 | ~2.1 L |
| Pregnant | 3.1 | ~2.3 L |
| Breastfeeding | 3.5 | ~2.6 L |
Population estimates. Individual needs vary.
| Beverage | Hydration | Notes |
|---|---|---|
| Water | Optimal | Zero kJ |
| Tea/coffee | Good | Moderate caffeine unlikely to dehydrate |
| Juice | Good | Limit ~125 mL/day |
| Sports drinks | Situational | For intense exercise >60 min |
| Alcohol | Poor | Diuretic |