What hot-weather racing teaches every endurance athlete: how to match sodium to sweat, how much carbohydrate per hour to aim for and when caffeine belongs in your plan.

Two threshold sessions in one day only work if you fuel both. Carbohydrate targets per hour, what to eat in the gap and a practical timeline for runners, cyclists and triathletes.

Heat makes every watt cost more. Here is what happens to your body when racing in the heat, plus practical protocols for acclimation, hydration, sodium and fuelling.