Pre Event Hydration - It’s all about the timing.

Pre Event Hydration - It’s all about the timing.

Every year, in the weeks leading up to a race, i’m often asked how do you know if you are hydrated properly on the morning of the race?

Both cyclists and runners are often in two minds about how to address the issue of hydration.

On the one side, you have those who consider throwing caution into the wind and drink excessive quantities of fluid as soon as they wake up to ensure they are hydrated.

On the other side, you have runners and cyclists who are more tempted to hold back on their fluids on the morning of the race, for fear that if they drink too much, they’ll need to join the ridiculously long queues for the toilet at the starting area.

So which tactic should you adopt?

As you’d expect, the best way to approach your pre-event nutrition is somewhere in-between.

If you’ve got a marathon, half marathon, 10k or cycling sportive coming up in the next few weeks, follow these tips to ensure you start the race at the perfect level of hydration.

Hydrate on waking

As soon as you get up in the morning, begin the hydration process. You will have been without any fluid for 6-8 hours and it’s a good idea to begin getting fluids in to hydrate your cells and muscles.

Avoid gulping down large quantities of fluid all in one go.

Drink little and often.

Coffee, water or electrolyte?

With regards to what type of fluid you should be drinking, the best advice is to stick with what you know.

On rising, if you usually have a coffee or tea then there is no reason why on the morning of your race should you avoid it.

Keep your routine as close to what you’re used to as possible.

Provided your general nutrition is of good quality, there’s no reason to consume electrolyte or sports drinks - but that’s not to say that it’s a bad idea either.

The 7-10% sugar and electrolyte solution in a sports drink can help to both hydrate you and raise your blood sugar levels, so provided you don’t go mad and drink several pints of it, then by all means have a sports drink or two.

The majority of your fluids however, should come in the form of good old fashioned water. How old school is that!?

But how much should you consume?

How much is too too much?

Knowing how much fluid to drink before a race is impossible to give an accurate answer to unless more is known about an individual’s physiology.


We are all different.

Our body composition, our endocrine (hormonal) system, our diet and our basal metabolic rate are just a few of the factors which determine how much fluid we need to drink on a daily basis - let alone before an event.

So to give an accurate figure in litres as to how much you need to drink to ensure we are sufficiently hydrated before the gun goes off, as you can see, is impossible.

However….. There is the wee test.

The Wee Test

Although the following test is a little crude (in more ways than one), it is commonly used by many amateur sports people who need a quick way to check their hydration status.

Looking closely at the colour of your urine might not be the most dignified part of your preparations, but the colour of the stream can tell you quite a lot about your hydration status.

Take a look at the image below:

As a general rule, the clearer your urine is, the better hydrated you are.

Once your urine is straw coloured or clear, there is little need to continue hydrating as it’ll simply pass out again without adding any benefit to your performance or hydration status.

In fact, over hydrating can be incredibly dangerous as a result of excessive salt being leached out of the body. This can lead to a potentially life threatening condition, which you can read more about here.

Anxiety, nerves and urination

The phrase, to have a “nervous wee” exists because of the profound effect that anxiety and general nervousness can have on the body’s need to visit the bathroom.

The reason why this is directly related to your hydration status, is that on the morning of your event, when you’re nervous about your upcoming race, your increased anxiety levels can make you urinate far more frequently than you physiologically need to.

Although it is not fully understood why we have a sudden urge to urinate when we’re anxious, factors such as muscles tension (causing the bladder to contract) and change in body chemistry due to a surge of adrenaline are all likely reasons.

These factors have a profound effect on the body and over the course of the hours leading up to the start of your race, can in some cases cause you to be more dehydrated than your fluid intake suggests you should be.

So, to help counter the effect of “nervous weeing” continue to hydrate (little and often) up to 45-60 minutes before your race is due to start.

This 45-60 minute window will give you plenty of time to take a final toilet stop (or two) before the race. Provided you began hydrating, little and often, the moment you woke up, you will not suddenly become dehydrated in this 45-60 minute window.

In summary

Hydrating before a race is never easy.

Due to the effect that our pre-race anxiety and nerves have on the body, some people may find that no matter how little they drink, they will still have frequent urges to use the toilet before the start of their race.

The best thing you can do is control the things you have direct control of, which means hydrating first thing in the morning and then reduce your fluid intake when you see that your urine is running clear.

Avoid drinking excessive quantities of fluid to avoid the risk of hyponatremia.

Most people will find that a sufficient quantity of fluid to consume before your race is 1.5-2 litres of fluid - from waking to the start of your race, but this figure is very general and should be taken only as a rough guide. Some runners and cyclists will need more, some will need less.

Anything more than 3 litres is excessive and should be avoided.

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