Performance nutrition model – Hydrate

By Alan Kenny, Head Nutritionist at Functional Training Ireland…

You can contact Alan for a private consult on


This is the last component of my performance nutrition model. This is the simplest, cheapest and quickest positive change that somebody can make to their nutrition. There is really no excuse for somebody not to be well hydrated, be they an athlete or not. I will go through some of the benefits and solutions now.


Why is Hydration so Important?


Our bodies are made up of approximately 70% water. Every single biological process in the body requires water at some level.  Research has shown that being dehydrated by as little as 2% can impair performance. This impairs both physical and mental function. This is part of the reason why most mistakes happen in the final 10 minutes of most field sports. We always hear about post training and re-hydration. Re-hydration is very important but I place more of an emphasis on pre-hydration.


Hydration status


The great thing about hydration is that we can constantly keep an eye on it. Self-monitoring your urine is the quickest and easiest way to do so. Use a handy colour chart like this.





This is very important and often overlooked. Pre-hydration isn’t just the few hours before your run or day before a race/match. This is your 24/7 hydration. You should aim to drink 3-4 litres of water every day.  One litre for every 25kg you weigh per day is a good start.




This will vary from person to person but a good general guideline is 100ml of water every 15 minutes.




Rehydrating is very important post competition. A very handy way to check your hydration status around training is to weigh yourself before and after a training session in the same clothes. The difference in weight pre and post training is the water weight that you have lost. You need to consume 1.5 litres of water for every kilogram of bodyweight lost during exercise to rehydrate. An electrolyte replacing product, such as a dioralyte sachet, is recommended for extremely hot environments when there is excessive sweat loss.


Simple Solutions


Always have a water bottle handy, one at work, one at home and one in the car is a good start. It is purely down to habit. You can also mark your bottle if you reuse one with 2 hour increments so you have to get down to each line through the day.

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