The nature of heat waves in the UK means you don’t always have time to acclimatise or heat train - though there’s an argument that we should start expecting them now. If you aren’t prepared for the heat, you need to change your goals for the race and take steps to mitigate the effects of heat.
Pre-race
Pre-cool as best you can and avoid standing around in the heat - find shade where it’s possible.
Soak your top in water and pour water on your head (make sure you’ve applied an anti-chafing balm if you’re wearing a sports bra).
Make up an ice slushie using ice and a sports drink. Keep it in a thermos and drink it 15-20 minutes before the start. The slushie part is important as the change of state (from solid to liquid) is more cooling than drinking cold water alone.
Keep your warm up shorter than usual, aim for just enough. Stay in the shade.
Start of the race
Try to line up along the edge rather than the middle of the pack so you’re not completely surrounded by other hot bodies and trapped hot air. Keep pouring water on yourself and your clothes. Use an ice bandana if you have one (soaking a fabric running cap in cold water just before the start also works).
You should have already adjusted your goal and expectations. Use out heat pace adjuster to get an idea of your new goal - this will tell you what pace to set out at.
Why do you have to slow down? Here’s what happens when we run in the heat
When we race in the heat, the body has to work much harder to control its temperature. As air temperature rises closer to skin temperature, the body loses less heat to the environment, meaning it relies more heavily on sweating for cooling. More blood is diverted to the skin, leaving less available for working muscles. Heart rate rises, perceived effort increases, and core temperature climbs fast. The result is that the same pace feels harder, fatigue hits sooner, and pace inevitably drops.
In temperatures that exceed skin temperature your body’s ability to cool itself is severely limited. This is the point where races might be cancelled, and your PB attempt should certainly be shelved.
During the race: it becomes a wet t-shirt contest
Take every opportunity to pour more water on yourself.
Start slower than your usual race pace (and effort) and monitor your body for signs of overheating. Your heart rate will be higher but make sure it isn’t rising rapidly. It might feel tempting to start faster with the expectation of slowing down as you heat up, but the faster you start the faster you’ll heat up.
If you’ve got your eye on the podium, be patient. Start smart and you may well reel in the fast starters towards the end of the race.
Who needs to be extra careful in the heat:
Runners taking medications that affect the brain as these medications can alter your body’s perception of heat and make heat-induced illness more likely.
Older runners - and children
Pregnant runners
Runners with chronic health conditions
Runners taking unregulated supplements
After the race
A drink with carbs and a little salt will help you rehydrate fast. Get in the shade. Pour more water on yourself if you’re still hot. Be mindful of staying cool for the rest of the day.
