Electrolytes: Your best friend on long distances
14. April 2026

Electrolytes are everywhere right now – including along the Copenhagen Marathon course. But what are they really, and when does it make sense to pay attention to them? You can learn more here

Electrolytes are minerals that help your body maintain fluid balance. They ensure that your muscles and nerves function properly. The most important ones are sodium, potassium, calcium, and magnesium. In other words, they are a fundamental part of what keeps your body running – both in everyday training and when you line up for a race.

When you train – and especially when you sweat – you don’t just lose fluids, you also lose electrolytes. On most shorter runs, this isn’t something you need to worry about, as your body is good at restoring the balance on its own. But as you move into longer distances like the half marathon and marathon, it becomes important to pay attention to your electrolyte intake, as a deficiency can start to affect your performance.

Some of the symptoms of low electrolyte levels include:

  • fatigue
  • decreasing energy levels
  • muscle cramps

This is your body’s way of telling you that your balance is off – and it’s something you should listen to.

Refuel at halfway
For many runners, the halfway mark in a marathon is both a mental and physical milestone. This is where your energy stores start to run low, and where you’ve lost a significant amount of electrolytes through sweat.

That’s why our partner Royal Unibrew has placed a Power Zone right at the 21.1-kilometer mark at Copenhagen Marathon. Here, you can refuel with Faxe Kondi Pro – and that’s a smart move. Faxe Kondi Pro is designed to meet your body’s needs during physical activity, providing electrolytes, magnesium, and vitamins that can help reduce fatigue and exhaustion.

One of the key benefits of Faxe Kondi Pro is that it is formulated to be easily absorbed by the body without putting unnecessary strain on your digestion. It is isotonic, meaning it has a composition similar to your body’s own blood plasma.

This allows the fluid to be absorbed quickly and contribute effectively to hydration – more efficiently than water alone. In addition, Faxe Kondi Pro contains carbohydrates, giving you an extra energy boost halfway through the course.

Royal Unibrew will also be ready with Faxe Kondi Pro for you at the finish line, in the refreshment area in Runners Area – right after you receive your medal.

But first, 42.195 amazing kilometers through Copenhagen await.