Fuelling Guides
Hydration in Cape Town summer heat
Dry southeaster, high evaporation and salt you never see. How to plan bottles and sodium for a Western Cape summer.
Cape Town summer fools people. A 26°C day with a stiff southeaster feels manageable because the wind evaporates sweat before you notice it, which is exactly why athletes finish the Cycle Tour or a Table Mountain trail loop several percent down on body mass without ever feeling that hot.
Measure your sweat rate once
- Weigh yourself in minimal kit before a one-hour session in typical summer conditions.
- Note everything you drink during the hour, in millilitres.
- Weigh yourself again immediately afterwards, towelled dry.
- Sweat rate ≈ (weight lost in kg × 1 000) + fluid drunk in ml. That is your millilitres per hour.
Most South African endurance athletes land between 500 and 1 200 ml per hour in summer. Aim to replace roughly 70 to 80 percent of that during the event — chasing 100 percent usually just sloshes.
Sodium is the part people skip
Sweat sodium concentration varies from about 500 mg per litre to over 1 500 mg per litre between individuals, and it does not change much with acclimatisation. If you cramp late, taste salt on your lips, or see crusted white lines on dark kit, plan 700 to 1 000 mg of sodium per hour rather than the token amount in a plain sports drink.
A hot-day template
| Phase | Fluid | Sodium |
|---|---|---|
| 2 hours before | 400–500 ml with one tab | ≈320 mg |
| Every hour of the event | 600–900 ml, drunk on a schedule | 500–900 mg |
| First hour after | 500 ml with a tab, plus recovery mix | ≈320 mg |
Nobody drinks enough in a headwind. The wind removes the evidence.
