Let your body adapt
Gradually building up the amount of exercise you do in hot weather will allow your body get used to it, a process called heat acclimatisation.
Generally, says Stearns, after seven to 14 days of regularly exercising in the heat your core temperature at rest drops, your sweat rate rises and your blood plasma volume increases. “You have this huge demand for blood flow. And blood is ultimately what’s going to be able to supply and support all of these physiological functions in the heat,” she says.
This adaptation helps your body respond better, she adds, helping to improve performance as well as decrease the risk of heat stress.
But this response is “transient”, says Jay. “If you don’t use it, you’ll lose it… If you don’t expose yourself to the heat, then those adaptations that you’ve primed will disappear.”
Know when to stop
While fatalities from exercising in the heat are relatively rare, heat exhaustion is becoming more common.
And if you exercise a lot, it doesn’t necessarily provide protection against heat exhaustion.
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Elite athletes can be at a higher risk of heatstroke than recreational exercisers because they are already used to pushing themselves “past their biological limits”, says Stearns. This could be dangerous as the intensity of the exercise is the primary driver of rising internal body temperature.
She therefore advises that “listening to your body and deliberately backing off the pace is your primary line of defence”.
If we adapt, pace ourselves and exercise early we can stay active even as the temperature rises. Heat related illness is still a risk so signs to look out for include dizziness, nausea, fatigue and palpitations. If any of these appear, stop immediately and cool down.
“I think the bigger message is that we should stop thinking of physical activity as something completely separate from climate,” says García-Witulski. “As heatwaves become more common, people will increasingly need to adapt not just whether they move, but when, where, and how they do it,” he adds.
* Melissa Hogenboom is a senior health correspondent at the BBC and author of Breadwinners and The Motherhood Complex. She is melissa_hogenboom on Instagram.
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