The number of people I’ve seen out running in this current heatwave, both at the peak of the day and without a water bottle, is frankly more than a little alarming.

Running in near 30°C heat (feels like way more when you take into account irradiated ground heat) can be risky, especially when you are not used to it. It is easy to become dehydrated and overheated, which can lead to excessive sweating, headaches, nausea, tiredness, dizziness and muscle cramps.

You’ll likely stop running well, and may even find you are not able to run at the same pace or cover the same distance as you might run in milder temperatures.

My 22-year-old son is fit as a butcher’s dog (though as a vegetarian I don’t think he’ll much appreciate that comparison!) and ran the Virtual Virgin Money London Marathon around Harrogate alongside me in the autumn.

He returned from a late afternoon run last week with a severe headache and nausea and had to go and lie down in a darkened room for several hours. He still felt out of sorts the next morning. It’s likely he hadn’t modified his pace to allow for the heat and despite having a bottle of water with him, simply hadn’t rehydrated enough, even for a relatively short 7km run.

The rule of thumb is to steer clear of running in heat if you are a young child, pregnant or elderly as the risks are obviously greater. However, there are some potentially serious risks whatever your age or fitness, especially when doing endurance runs.

Serious consequences

Having witnessed healthy young people collapsing before the finish line whilst running races in the heat and humidity of Singapore, I’ve seen firsthand the toll pushing yourself regardless in extreme temperatures can have on the body, when running for a long time and not getting the right fluid intake balance.

In many cases these are runners who have most likely trained in different conditions. Whilst running London in April 2018, its hottest race on record, I witnessed many people collapsing because they weren’t used to training in such high temperatures.

The facts are simple; there can be serious health consequences to exercising in hot weather — regardless of activity, length of time or distance — such as heat exhaustion and heat stroke.

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I recall finishing my second London Marathon (not a particularly hot one) shortly after a young lad collapsed crossing the finish line. He was surrounded by medics. Sadly this young man died, apparently due to flooding his body with too much water after opting to not take onboard any energy drinks or packs during the race.

It’s a fine balance, but one you must follow if you are going to train for any kind of endurance run and stay safe. Be it heat or distance, or with some races, like those in the Sahara, a combination of both.

If you are going to run in extreme temperatures, and let’s face it we don’t get a whole lot of practice in North Yorkshire, listen to your body and take sensible precautions to avoid getting overheated, even if you are just going out for half an hour.

Takeaway message

✔ Drink plenty of fluids to stay hydrated, but don’t overdo it. Take small sips regularly.
✔ Avoid running in the heat of the day (between 11am and 3pm), dress light and ensure you wear breathable clothing to help regulate your body temperature.
✔ Slow down. Don’t try to run at your normal pace.

✔ Give yourself a chance to acclimatise to the temperature, usually a couple of weeks. Until then slow your pace!

REMEMBER... it really does come down to laziness where carrying a small bottle of water is concerned! Don’t be daft, be sensible, take a bottle and rehydrate as you run!

Sam Blakey is an international personal trainer working across the UK. She also has clients in the US, Singapore, Thailand and South Africa and ran a successful fitness company in Singapore before moving to Harrogate four years ago. She describes herself as a reluctant runner, who took up marathon running just before turning 40 to escape her five kids; she has since run eight marathons on three continents and completed several half marathons.