Running in the heat: what it does to your body and how to deal with it

There’s a reason I’ve done more spring marathons than autumn ones in recent years. Training through the summer is no joke. I will take rain, flooding and below-freezing temperatures for the majority of my training block over hot weather every single time. At least when it’s cold you can add another layer.

Obviously summer training has its advantages: the longer days are nice, and often you can get some brilliant early morning or evening runs in. But if you’re currently deep in an autumn marathon training plan, sweating through sessions that felt fine six weeks ago and regretting every life choice that led you to sign up for a 26.2 mile race in October, this post is for you.

Here’s what the heat is actually doing to your body, and how to adjust your training so you come out the other side in better shape than you went in.

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Why running in the heat feels so much harder

First things first: it is harder to run when it’s hot. This is not a mental weakness or a fitness problem, there is a proper physiological reason why your easy pace feels anything but easy when the temperature climbs.