So you’re finally here! There’s still 26.2 miles to go but you should feel proud that you’ve come this far.

Training for a marathon is not an easy thing to do. Juggling a busy life with having to complete a weekly quota of miles - all during the winter months - is not anyone’s idea of a cup of tea!

To help you get the most out of your race, we’ve put together some guidelines to help you avoid undoing all that hard work by neglecting your hydration on the day.

Your strategy for taking in fluid on race day can have a big effect on your marathon performance, so you need to consider this as an integral part of your race preparations.

Day Before Race

It is important that you stay hydrated the day before a race. Keep a water bottle handy so you remember to drink regularly throughout the day. This is especially important if you are travelling to the race venue on this day, as it is easy to forget to drink. Remember to take small sips and don’t drink too much. 

Alcohol is a diuretic so it’s better to avoid it completely. If you overindulge, you may feel below par the next day.

Race Day

On race day, you need to get up early enough to eat and digest your pre-race meal. Drink 350 - 500 ml of water 2 - 4 hours before the race, then another 125–250 ml or just enough to satisfy your thirst during the warm up, or about 45 minutes before the gun goes off. 

During the marathon, there are no strict rules about how much to drink as this depends on how much fluid you lose through sweat.

By now you probably have a good idea of how much to drink if you’ve practised a drinking strategy in training, but if the temperature soars on race day then you must adapt your drinking strategy to make up for the extra fluid you will lose. You should drink enough so you don’t lose more than about 2% - 3% of your body weight during the race.

You must also be aware that drinking more fluid than you’ve lost can increases the risk of hyponatraemia (low levels of sodium in the blood), which can be dangerous. As a rough guide, aim to drink 125–250 ml – about two or three big swigs – every 15 to 20 minutes or according to thirst.

Avoid drinking large amounts in one go. You may be tempted to gulp water, but should try and sip instead. The maximum you should drink during the race is the amount you’ve lost as sweat. Use whichever drinking method you have trained with and don’t change your approach just for the race.

Don’t feel like you have to drink at every water station on the course but also don’t be tempted to skip the early stations to gain time, particularly if it’s a warm, humid day. Dehydration later on will slow you down even more. Remember that slowing a little as you run through the early stops while drinking may add 1 or 2 minutes to your time but it can repay you with 10 or 20 minutes gained by the finish of the marathon.

Stick with whatever you have used in training and don’t try anything new. Continue drinking until the last few miles.

If you've been drinking according to your thirst, and taking in carbohydrates throughout the race, you should be able to maintain your target pace to the finish line.

After the Race

After the race you need to replace the fluid you have lost. Try to drink around 500 ml, little and often, in the first 30 minutes after the race, and then keep sipping every 5 to 10 minutes until you are passing pale coloured urine again. At this stage you may want to consider drinking energy drinks to ensue you are replacing lost fluids as well as salts and minerals.

Signs that you MAY BE dehydrated during the race:
  • A dry mouth
  • Extreme thirst
  • Unusually lacking in energy
  • Fatiguing early during the race
  • Feeling excessively hot
  • Nausea
  • A bad headache
  • Dizziness