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Water bottle anyone?

How can dehydration affect our performance?

If there is one sure fire way to wreck your match day performance, being poorly hydrated is it. Water is essential to life and essential to all functions in the body. We lose water through breathing, sweating, urinary and fecal output. If we do not replace these lost fluids, we can become dehydrated.

During exercise, most of the water losses are incurred as a result of sweating. Sweating is a vital function. It rids your body of excess heat produced during exercise, maintaining your core temperature within safe limits - around 37 - 38 degrees C.

Sweat rates can vary depending on the temperature and humidity, the intensity of the exercise and the individual. Heavier people will sweat more than lighter people and sweat rates can also vary considerably from person to person. If fluid losses exceed fluid consumption, then dehydration ensues.

During an hour of high intensity gaelic games in hot weather, players can lose up to 2 - 4% of body weight in fluid. For an 80kg person, this equates to 1.5 -2.5 litres of water.

Mild dehydration of only 2% of body weight loss can result in a 10% reduction in performance.

Many studies below have shown how varying levels of dehydration can negatively influence physical and mental performance.

It is imperative that players arrive at the game fully hydrated and continue to keep hydrated during the warm up and throughout the match.

How to assess Hydration?

There are three ways we can become more aware of how hydrated we are. The W.U.T. is a simple guide that is very easy to use. It involves monitoring Weight, Urine colour and Thirst. This can be done in the morning.

Ask yourself three different questions.

1. Weight: Is my body weight lower this morning than yesterday morning?

2. Urine Colour: Is my morning urine colour 'bright yellow' or 'orange'?

3. Thirst: Am I thirsty?

1 yes answer: may be dehydrated

2 yes answers: likely dehydrated

3 yes answers: very likely dehydrated

How much do I need daily?

  • Drink a litre for every 25kg of weight. 75kg person should drink approximately 3 litres.

  • Drink an extra litre for every hour of exercise.

  • Drink little and often throughout rather than a large quantity in one go which would result in greater urination rates and fluid loss.

  • Can come in many forms, smoothies, tea and coffee and food especially fruit and vegetables

What about sports drinks?

Sports drinks are specially designed to provide fluid, sugars and electrolytes to aid performance and improve recovery. Whilst predominately used in longer duration events over 2 hours they have been seen to provide benefits for sports such as gaelic matches which may require activity for 90 minutes including the match and warm up. For anyone who exercises for less than an hour, sports drinks are probably not necessary.

For someone playing an intense match and are sweating heavily, a homemade or commercial sports drink may improve performance and delay fatigue. The sugars they contain not only provide fuel for exercising muscles but also speed up the absorption of water into the bloodstream. Try to drink 1 litre from the start of the warm up through to half time and during the second half.

Homemade sports drinks that provide 50-60g carbohydrates

Option 1: Add 100ml of cordial and a pinch of sea salt to a litre bottle. Top with water.

Option 2: Add 500ml of apple juice and a pinch of sea salt to a litre bottle. Top with water.

It is best to practice this drinking routine during a challenge match or training session to see how the body reacts. It is never a good idea to try something new on a big match day!

Sports drinks are not recommended/necessary during regular training sessions where a low glycogen availability can actually help the training effect.

BEWARE: Sports drinks are very high in sugar and are best consumed around exercise. Drinking sports drinks when you have not exercised is a sure fire way to accumulate body fat!

Can you over-consume water?

More water does to not equate to an even better performance. There is no need to drink excessive amount of fluids and they may even be harmful. Too much fluid causes the sodium in the body to become too diluted and can cause a condition called hyponatraemia. This can lead to dizziness, lethargy and nausea and will result in a reduction in performance. As long as your urine is relatively clear and you are drinking according to thirst, you will be fine and will save yourself the multiple extra visits to the toilet.

What about electrolytes?

Unless you are exercising for longer than 2 hours in hot humid conditions and sweating profusely, then it will not be necessary to add electrolytes to your drinks. Therefore GAA players who have been tapering their training and eating and drinking regularly in the lead up to a match will probably not need to worry about extra electrolytes.


Dehydration can destroy your performance. Ensure urine is clear before you exercise. Try to drink 1 litre per 25kg of bodyweight per day.

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