How to stay cool in summer

Whilst summer may still be a few months away, the heat that comes with it is well and truly here. With the mercury hitting as high as 40 degrees, how can you stay fit without doing yourself some serious damage?

Stay hydrated

Dehydration is the your biggest concern when riding in the heat. When the U.S military studied the effects of environmental temperature, they found that in hot, dry conditions (28 degrees), soldiers sweat up to 4.7 times as much as comparable activity in neutral conditions (13 degrees) (1).

Maintaining your fluids is an essential part of riding during summer, as a fluid loss of as little as 1% of your body weight can result in neurological deficits. It’s also important to remember that in your body, water cannot transport itself, it can only follow ions. If you’re sweating, it means you’re losing electrolytes, so if you’re going out for longer than an hour, be sure to be bring a sports drink with plenty of salt in it!

A good guide is to replace the amount of water lost through sweat by 1.5 times. As a rule of thumb, during exercise on a hot day, the average human will sweat between one to two litres per hour. This of course is a very broad generalisation, but it gives an idea as to how much water you need to be carrying!

Wear white

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There’s a reason Chris Froome wore white during the French summer. Well, when he wasn’t in yellow.

Don’t go out in the summer in your full stealth kit – black absorbs all visible light, that light energy is then turned into heat by exciting the molecules within your clothing. White, on the other hand, reflects all visible light, keeping you cool during the summer months.

Train

If your schedule, training or upcoming races require you to ride in the heat, the best way to reduce the stress placed on your body by heat is to train in the heat. When your body is placed under the additional stressor of raised temperatures, it engenders a physiological change known as heat acclimatisation (2). Heat acclimatisation is a series of bodily adaptations that occur over two weeks after first starting to train. These changes include increased salt retention, improved control of cardiovascular function, and decreased susceptibility to heat stroke as well as dramatically reduced cortisol levels, a marker of physiological stress.

It is important to note that to see these changes, training in the heat needs to be on a daily basis, and can be mitigated by dehydration, so train regularly and carry lots of water.

Slip, Slop, Slap

Sunburn is never fun, not only is it the number one cause of melanoma, but if you get burnt badly, it’ll keep you off the bike for a week.

Take it easy

Cycling in the heat is harder on your body, and it does come with added risks. Start out with shorter rides, and stop as soon as you feel dizzy or you feel a headache coming on.

  1. Gisolfi, C. (1993). Water requirements during exercise in the heat. Nutritional Needs in Hot Environments: Applications for Military Personnel in Field Operations, Committee on Military Nutrition Research, Institute of Medicine, 87-96.
  2. Armstrong, L. E. (1998). Heat acclimatization. Encyclopedia of sports medicine and science.

About Tim_Davis@Pushys

I'm a Science Graduate and Medical student at the University of Queensland, specialising in anatomy and physiology. More importantly, I'm all for any type of riding; road, mountain, dirt jumping, I love it all! Let me know if there is anything you want to know about nutrition and health, and I'll do my best to help you out!

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