Water is essential for nearly every bodily function. Understanding fluid needs supports performance and health.
Water makes up 50–80 % of body weight. Even mild dehydration (1–2 % loss) may impair concentration, mood and physical performance.
| Group | Total (L/day) | From Beverages |
|---|---|---|
| Men 19–70 | 3.4 | ~2.6 L (≈ 10 cups) |
| Women 19–70 | 2.8 | ~2.1 L (≈ 8 cups) |
| Pregnant | 3.1 | ~2.3 L |
| Breastfeeding | 3.5 | ~2.6 L |
Population estimates from Australian Nutrient Reference Values. Individual needs vary.
| Beverage | Hydration | Notes |
|---|---|---|
| Plain water | Optimal | Zero kJ |
| Tea / coffee | Good | ~400 mg caffeine/day unlikely to dehydrate |
| Fruit juice | Good | Limit ~125 mL/day |
| Sports drinks | Situational | For intense exercise > 60 min |
| Alcohol | Poor | Diuretic; pair with water |