Keeping your cool

With climate change comes the reality of hotter days. When cycle touring, that has real-world implications for you, in multiple ways.


No matter how advanced we may think of ourselves as a species, the fact remains that we’re still only mammals. That means our bodies like to remain with a core temperature of around 37 degrees Celsius.

In the depth of winter, that’s comparatively easy to achieve, simply by adding more layers of insulation. This is why humans survived the Ice Age, even though we were far more primitive back then.

On hot days, maintaining your core temperature at no more than around 37 degrees can rapidly become a problem. Remember, physical activity generates additional body heat, and cycling a laden touring bike up big hills will certainly raise your body temperature.

Your brain

The human brain is much like jelly in consistency. If you removed jelly from the fridge, and placed it outside, on a sweltering hot day, sooner or later it will start melting. Your brain is the same, and the danger point is 42 degrees Celsius. If your core temperature exceeds that, you are at risk of permanent brain damage, or even death.

Of course, unlike a bowl of jelly, our bodies have a built-in mechanism to help us cool down: we sweat. Basic physics teaches us that liquid evaporation causes a drop in temperature, and that’s exactly how sweating cools our bodies.

However, there’s a limit to it. Science teaches us of something called the wet bulb effect, and that kicks in at around 35 degrees Celsius. That simply means, in areas of high humidity (like the UK), sweating stops cooling our bodies once the outside temperature hits 35 C.

In fact, with a wet-bulb temperature of 35 C, scientists believe the limit of human endurance is around six hours of exposure. In areas where relative humidity is far lower, the wet-bulb temperature can be far higher, which explains why people can function in 40 C heat in a dry desert.

Coping strategies

There are simple changes you can make to better protect yourself. These start with changing the times that you will be riding. Get up earlier, and set off far earlier, then stop for a few hours when the temperature reaches the highest forecast.

Crucially, during that time, find shade and do not sit out in the sun! After all, you’re trying to prevent your core temperature rising, remember? Now you actually have a health reason to sit in that café and enjoying another ice-cold beverage!

When the temperature starts dropping again towards later afternoon, you can set off again, and cycle into the evening.

Try to stay out of the sun as much as you can, and whenever you stop, immediately seek shade. Also, when cycling on hot days, dress in light colours, and avoid excess alcohol.

Heat stroke

I want you to memorise the following symptoms. If anyone cycling with you experience any of these, call 999 immediately, and get them off their bike and into shade!

  • Confusion, altered mental status and/or slurred speech
  • The person becomes unconscious
  • Hot, dry skin
  • Seizures
  • Very high body temperature
  • A very fast heartbeat
  • Shortness of breath (relative to any exertion)

People die from heat stroke, and your actions can save their lives.

Heat exhaustion

A precursor to heat stroke is heat exhaustion, and it’s equally important to know the symptoms:

  • Tiredness (relative to their fitness level and exertion)
  • Dizziness
  • Headache
  • Feeling sick, or being sick
  • Excessive sweating
  • Cramps in the arms, legs and stomach
  • Fast breathing and/or heartbeat (relative to their level of fitness and the exertion they did)
  • High temperature
  • Being very thirsty
  • Feeling weak

Children share the symptoms with adults, but they can also become extremely irritable. If you (or a riding companion) experience any of these symptoms, then immediately stop cycling, and get into shade.

Cooling down

If it is an option, go to a cool place. Again, you have a health reason to visit that air-conditioned café! However, if this happens in the middle of nowhere, things change.

For starters, get into shade. If there’s no shade available, create some! Consider pitching your tent, or make a makeshift shelter from your bike(s), and hang items of clothing to create shade. If there’s a stream nearby, and you can safely do so, get them partly submerged (even if that means just their feet are in the water. Just do not drink from the stream, or get its water onto your face.

If you have cool water available, let them drink it. Even warm(ish) water can help cool them down if you splash it over them, then fan them. Usually, it takes at least 30 minutes to start feeling better.

Secret emergency tip: If you use CO2 cartridges to inflate your wheels, you will know they need a protective cover, to stop your hand freezing onto them when they discharge.

What this means is you can dangle a CO2 cartridge in water, and open the valve, to vent all the CO2. This will cause the cartridge to form ice on the outside, and will cool down the water. If you can do this, and keep the water clean enough, let the person drink it. If not, pour it over them, to help cool them down.

Obviously, that’s an absolute emergency measure, and you need to be careful, as you can easily get ice burns from trying to do that.

Other options

A better, and far safer option would be to use instant ice packs, such as these. These packs require no prior freezing, nor do they need keeping cold. They contain a mix of urea and water, which is so safe it’s been successfully used to treat dehydration, plus many other uses.

Just a word of caution: these packs can get cold enough to cause a burn, so do not apply them to bare skin! Instead, always wrap them in cloth of some sort (your cycling jersey, if needs be). Also, while urea is a safe, non-toxic compound, the plastic wrapper is still a waste product, so please only use these to cool down people who are at risk of heat exhaustion and/or heat stroke, and don’t waste it on cooling down your beers?

You can of course use an instant ice pack to cool down water, and have the effected person drink the cold water, so they can reduce their core temperature even faster.

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