Hydration: The Science and Importance for Athletes

As summer heats up — especially in dry regions like Bloemfontein — hydration becomes one of the most powerful tools athletes can use to perform at their best. Staying properly hydrated isn’t just about quenching thirst; it’s about maintaining the delicate balance of water, electrolytes, and energy that keeps the body functioning under stress.

Why Fluids Matter in Sport

When we exercise, the body regulates its temperature by sweating to cool itself. Sweat is mostly water, but it also carries away electrolytes like sodium and potassium, which are essential for muscle and nerve function. Losing too much fluid or too many electrolytes disrupts these systems, leading to fatigue, cramps, dizziness, or even heat illness.

The Hidden Keys

• Sodium (Na⁺): Vital for fluid balance and nerve transmission. It’s especially important for muscle contraction. Without enough sodium, muscles cramp more easily, and the body struggles to retain the water you drink.

• Potassium (K⁺): Works hand-in-hand with sodium but is concentrated inside muscle cells. It supports energy metabolism and recovery. Low potassium can cause muscle weakness, irregular heart rhythms, and slower recovery.

• Sweat losses: The exact amount varies by individual, but athletes typically lose 500–1,500 mg of sodium per liter of sweat. Potassium losses are smaller but still significant. Replacing only water during long, sweaty sessions can dilute blood sodium — a condition called hyponatremia — which ranges from painful cramps to dangerous heart rhythm disturbances.

Drink Proactively, Not Reactively

Relying on thirst alone is risky:

• The thirst mechanism lags behind actual fluid loss. By the time you feel thirsty, you may already be 2% dehydrated.

• That 2% drop is enough to reduce endurance, slow reaction time, and make exercise feel much harder.

• In hot, dry climates, sweat evaporates quickly, so you may not even notice how much you’re losing.

Bottom line: if you wait until you’re thirsty, you’re already too late.

Hydration Guidelines for Athletes

• Baseline: 30–35 ml of fluid per kilogram of body weight daily.

• Before exercise: 300–500 ml, 1–2 hours before.

• During exercise: 150–250 ml every 15–20 minutes, adjusting for heat and intensity.

• After exercise: Replace 1–1.5 L for every kilogram lost through sweat.

Choosing the Right Fluids

• Water: Perfect for sessions under an hour at moderate intensity.

• Electrolyte drinks: Best for longer or high-intensity sessions, or in hot conditions. They replace sodium and potassium while providing quick carbohydrates for energy.

• DIY option: Mix water, a small pinch of salt, and diluted fruit juice for a cost-effective homemade electrolyte solution.

The Bottom Line

Hydration is more than just drinking water — it’s about replacing what the body loses: fluids and electrolytes. Athletes who understand the science — sodium and potassium for muscle function, and proactive drinking to stay ahead of thirst — gain a clear advantage. They’ll perform stronger, recover faster, and stay safer in the heat.