Too hot to trot?

A hot summer is good news for braais and beer gardens, but bad news for running performance. Here's how to beat the heat.

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There's no more vivid image of the heat's impact on running performance than Scotsman Callum Hawkins' dramatic collapse at the 2018 Commonwealth Games. Hawkins was leading the marathon by two minutes, with only about three kays to go, when he collapsed with heat exhaustion.

On Australia's Gold Coast, where the race was held, temperatures had tipped over 30°C. That's not out of the ordinary in Oz, and it's not unusual for us in SA to face similar tough summer conditions. Even the UK had their hottest summer on record last year, and the thermometer hitting 34°C in June this year.

In winter, we imagine running in the summer sun as an idyllic affair; in reality, every step can be a sweaty effort; it leaves you fatigued, increases your recovery time and affects the intensity and volume of your next run. A far from enjoyable experience, and a serious threat to your autumn PB.

Thankfully, there are measures you can take to counteract the increased effects of our local star. But first, you need to understand what's going on in your body when things heat up. "It's really down to core temperature and its impact on a variety of systems," says Professor Stephen Cheung, head of the environmental ergonomics laboratory at Brock University in Ontario, Canada.

When running in the heat, our core temperature will climb from its optimal 37-38°C to 39-40°C and possibly beyond, with heat exhaustion likely between 40°C and 41°C. "As a snapshot, this rise in temperature alters brain chemistry and impairs cognitive function," says Cheung. "It also changes gut blood flow, causing leakage into the system; it increases free radical damage.... it's not simply a case of 'core temperature rises and you feel uncomfortable"."