Hydration for Training Through a South African Summer

Hydration for training in hot weather is one of the few areas where people manage to err in both directions. Some arrive at a summer session already short, and others drink so much plain water that they dilute themselves and feel worse.

Sodium matters as much as volume

Sweat is not just water. It carries sodium, and in a long hot session you can lose a meaningful amount of it. Replacing the fluid without replacing the sodium is what leaves people bloated, headachy and flat despite drinking plenty. For sessions over about an hour in real heat, an electrolyte tab or a pinch of salt in the bottle does more than another litre of water.

Work out your own sweat rate

Generic advice about litres per day is close to useless because sweat rates vary enormously. Weigh yourself before and after an hour long session in similar conditions, without drinking. Each kilogram lost is roughly a litre of sweat. That single measurement tells you more about your own needs than any chart.

Practical rules for a Cape Town summer

Heat, wind and a strong sun make southern summer training harsher than the temperature alone suggests.

• Train early or late, since midday sessions in peak summer cost far more than they give
• Drink to thirst during easy sessions rather than forcing a schedule
• Add electrolytes for anything over an hour, or any session where you finish visibly salty
• Check urine colour first thing in the morning as a rough daily gauge
• Build heat tolerance gradually over two to three weeks rather than in one brutal session

Frequently asked questions

• Can you drink too much water? Yes. Overdrinking plain water during long efforts dilutes blood sodium and is genuinely dangerous, though rare.
• Do I need a sports drink for a 45 minute run? No. Water is fine for most sessions under an hour unless it is extremely hot.
• Does coffee dehydrate me? Not meaningfully at normal intakes. The fluid in the coffee more than offsets the mild diuretic effect.