What are electrolytes and why are they so important to marathon training

18 December 2018

What are electrolytes and why are they so important to marathon training

Sarah Trimble Nutrition from Framar Health updates us on what electrolytes are and why they are so important to marathon training.

• Sports drinks are often marketed as a source of electrolytes but how do they support exercise performance and marathon training and do we really need extra electrolytes every time we exercise?


• Electrolytes are substances that conduct electricity when dissolved in water and these electrical currents are essential for a number of our body functions – especially functions that relate to exercise. Electrolytes regulate the nerve impulses that control muscle contraction and also control the flow of fluid in and out of our cells – therefore they are key to muscle function and to hydration.


• Without the correct electrolytes (or the correct balance of electrolytes), your muscles may become weak and you may experience cramps, twitches or spasms. For example, a muscle needs calcium, sodium, and potassium to contract. When these substances become imbalanced, it can lead to either muscle weakness or excessive contraction.

• These electrolytes work in combination to promote the body’s central functions, so it is not enough to focus simply on the ‘most important’ one but to try and get a balance of all of these from our diet.

• For many of us, sufficient levels of electrolytes can be found in our diets. Fruits and vegetables are great sources of electrolytes so if your diet is rich in these foods you should be fine – for the duration of your marathon training it is important to try and get plenty of calcium, magnesium, potassium and sodium in your diet – great source include all green leafy vegetables, bananas, sweet potatoes, tomatoes and celery.  Follow us for plenty of electrolyte-rich recipe ideas over this week and coming months.

• However, for longer runs if you are training for 2 hours or more you will need to replace sodium, magnesium, calcium and potassium lost through sweat. Drinking plain water can be counterproductive as this can further dilute blood electrolyte levels. So for those days when you are out for a long run you will need an electrolyte based drink.

• Viridian Electrolyte Fix, Hi 5 Electrolyte Sports Drink and Ener-C electrolyte sachets are all great alternatives to sports drinks that are often packed full of sugar.