Why Hydration Matters
Water makes up 50-80% of body weight and is involved in temperature regulation, nutrient transport, joint lubrication and waste removal. Even mild dehydration (1-2% loss) may impair concentration, mood and physical performance.
Adequate Intake
Australian Nutrient Reference Values suggest these AI levels for total water (food + beverages):
| Group | Total (L/day) | From Beverages |
|---|---|---|
| Men 19-70 | 3.4 | ~2.6 L (about 10 cups) |
| Women 19-70 | 2.8 | ~2.1 L (about 8 cups) |
| Pregnant | 3.1 | ~2.3 L |
| Breastfeeding | 3.5 | ~2.6 L |
Population estimates. Individual needs vary with body size, activity, climate and health. Hot conditions or intense exercise may increase requirements substantially.
During Exercise
- Before (2-3 hrs): 400-600 mL water.
- During: 150-250 mL every 15-20 min. Electrolyte drink may suit sessions over 60 min.
- After: 1.25-1.5 L per 1 kg lost. Weigh before and after.
Signs of Dehydration
- Dark urine (aim for pale straw)
- Infrequent urination
- Dry mouth or lips
- Fatigue or light-headedness
- Headache
- Reduced concentration
Beverage Comparison
| Beverage | Hydration | Notes |
|---|---|---|
| Plain water | Optimal | Zero kJ; most accessible |
| Tea / coffee | Good | ~400 mg caffeine/day unlikely to dehydrate |
| Fruit juice | Good | High natural sugars; limit ~125 mL/day |
| Sports drinks | Situational | Useful for intense exercise over 60 min |
| Alcohol | Poor | Diuretic effect; pair with water |
Tips for Australian Climates
- Carry a reusable bottle throughout the day.
- Start each meal with a glass of water.
- Include water-rich foods: cucumber, watermelon, oranges.
- In hot weather increase proactively — do not wait for thirst.
- Monitor urine colour as a simple indicator.
Disclaimer: General education only. Those with kidney or heart conditions should consult their doctor. Over-hydration (hyponatraemia) is also a risk during prolonged endurance events.