Who would have guessed? You need to drink fluids whilst riding.

Seems pretty damn simple right?  Don’t be fooled, plenty of money has been spent researching when, what, where and why we need to drink whilst riding.

First and foremost, you need to avoid dehydration. So obviously, when you’re riding, you’re exerting energy, friction then causes some of this energy to be released as heat, causing you to sweat as an autonomic attempt to cool you down.

When combined with a hot summers day, you can sweat up to 4 litres per hour, which, if not adequately managed can result in cramps, fainting, seizures and eventually death.   Therefore it’s essential to keep drinking water, as a loss of as little as 2% of your bodys’ mass through sweat will result in significant performance deficits, and a loss of 4% is potentially life threatening.  So how to avoid dehydration;

  • Carry plenty of water with you
  • Start your ride hydrated, but not excessively so.
  • Try and match your drinking rate with your sweating rate
  • Don’t ride in excess heat if you can avoid it.


This graph shows how much the ambient temperature affects endurance performance, and highlights the need to hydrate.

This graph shows how quickly heat causes dehydration, and then how efficiently this then results in a performance reduction.  However, the study that produced this graph shows that if you rehydrate, the reduction is partially reversed, and is completely mitigated by staying hydrated to begin with.


We are so often told that we need to constantly be drinking as much electrolyte fluid as we can,

but as far as current research can tell, we may not need to.

At least for shorter rides. If you are a 70kg male athlete sweating for 2 hours, you would only lose about 58 grams of sodium, the main electrolyte in energy drinks, through sweat. This equates to approximately 10% of your bodies total storage of sodium, and generally losing this much sodium won’t do you any damage.

The other major electrolytes such as Magnesium and Potassium aren’t really lost in sweat, and don’t need to be replaced whilst riding. 13123300_10153652073485829_5133920245136692091_o

Hmmm…. Not the kind of hydration I meant.

However there is nothing wrong with adding electrolytes to your water, and the flavouring that is generally included increases the rate at which you’re likely to drink, and that, in turn, is going to decrease your chances of dehydration.

Although if you are going to be heading out for longer than 2 hours you should really take out some electrolyte fluid, to avoid dropping your blood sodium levels too low.

But, what type of electrolytes do you need? A quick google search brings up a mind boggling amount of different powders, tablets, shot or blocks that all promise different things. The first thing you need to look for is an isotonic solution. This means that it will maintain the sodium level in your blood stream keeping the red blood cells in your body at their normal size. The next thing you should look for is sodium content.


Generally the more specific compounds, such as sodium, are measured in milligrams, so to convert to grams, just divide by 1000.  Anywhere around 300 milligrams per serving will be enough to prevent any serious sodium loss, but be sure to check the recommended usages on each specific product as well, as many recommend up to 4 servings per hour. Beyond that, not much else matters, just choose a flavour you like, and a product you can afford. You’ll notice that many sports drinks contain carbohydrates. This is to maintain your energy levels whilst cycling, which I’ll explain in further depth in a subsequent article.

So to avoid dehydration, and to stay performing at your peak, what do you need to do? Firstly, start your ride hydrated, and bring plenty of water with you, bring electrolytes with you if you’re going out for more than 2 hours, and avoid rides in the extreme heat where possible.

If you’re looking to stock up on electrolytes, be sure to check out the hydration category at


Edward F Coyle (2004) Fluid and fuel intake during exercise, Journal of
Sports Sciences, 22:1, 39-55, DOI:
Bardis, C. N., Kavouras, S. A., Adams, J. D., Geladas, N. D., Panagiotakos, D. B., & Sidossis, L. S. (2017). Prescribed Drinking Leads to Better Cycling Performance than Ad Libitum Drinking. Medicine & Science in Sports & Exercise.

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