Q. I read that it's a good idea to increase electrolyte intake a week before an Ironman in a hot climate. (I'm doing Ironman Nice in June.) What's your advice?
A. Warm weather and humidity are important considerations when it comes to planning your hydration strategy. Other factors that affect sweat loss include the type of activity and the intensity of exercise.
It's not possible to prescribe a fluid- replacement plan to meet everyone's needs but an easy way to estimate your needs is by weighing yourself before and after a session. (One kilogram of weight loss is equivalent to one litre of fluid.) Once you know your sweat loss you can prepare your fluid-replacement strategy for training and races.
For an event such as Ironman Nice ensure you hydrate with plenty of water in the days leading up to the race. Aim to drink regularly throughout the day (a minimum of 6-8 glasses or 1 litre daily). You also need to drink regularly during exercise and rehydrate fully afterwards.
Electrolytes are lost through sweat and this can lead to cramps and dehydration. Replacing electrolytes is essential if you want to perform at your best. Your idea to increase electrolyte intake in the days before the event is therefore a good one.
Coconut water has an excellent electrolyte balance. Another good option is Elete water, which is concentrated and very portable (eletewater.co.uk).
Bear in mind that if you consume electrolytes in excessive amounts you may suffer loose bowel movements, which you need to avoid before and, especially, during an event. Use your training sessions to find what works best for you. If you experience loose stools, reduce the quantity of the electrolyte solution you're using.
On race day start drinking early in the race. Continue to regularly drink small amounts. Most athletes can tolerate 200-300ml every 15-20 mins but this will vary with the intensity of the exercise.
You are more likely to drink them if the drinks are cool, palatable and easily available - know where your drinks stations are before you race. Sports drinks are ideal; use the one available on the day or try some of the natural sports drinks on the market.
Henrietta Bailey is a nutritionist who works as part of the Pure Sports Medicine team (puresportsmed.com). She specialises in sports nutrition and performance, obesity, cardiovascular issues, and diabetes and insulin resistance. She has worked with professional athletes and non-elites. She is a member of the Nutrition Therapy Council (NTC) and the British Association for Nutrition Therapy (BANT).