Electrolytes Explained: Do You Really Need Them? (UK 2026)

Walk into any supermarket or scroll any fitness feed and you will see electrolyte tablets, powders and brightly coloured sports drinks promising sharper sessions and faster recovery. They are one of the fastest growing corners of the wellness aisle. So it is worth asking a simple question: do you actually need them? For most people, most of the time, the honest answer is no. But there are real situations where electrolytes matter, and getting them right can make a long, hot session feel far more comfortable. Here is what the evidence says, minus the marketing.

What are electrolytes, and what do they actually do?

Electrolytes are minerals that carry a small electrical charge when they dissolve in the fluid in and around your cells. The main ones are sodium, potassium, magnesium, calcium and chloride. They are not an exotic supplement, they are simply part of the food you already eat and the fluid already in your body.

Their job is quietly essential. Electrolytes help control fluid balance, which is how water is shared between your blood, your cells and the space around them. They also help your nerves fire and your muscles contract and relax. Sodium is the main electrolyte in the fluid outside your cells and the one you lose most in sweat. Potassium works alongside it inside your cells, while magnesium and calcium play their own supporting roles in how muscles and nerves function.

When you sweat, you lose water and electrolytes together, mostly sodium with smaller amounts of potassium, magnesium and calcium. Lose enough without replacing them and fluid balance can drift, which is where the familiar warnings about cramp and fatigue come from. The key word, though, is enough.

Do you get enough from a normal diet?

For most people, yes. A normal, varied diet supplies plenty of electrolytes across the day. Sodium comes from salt in cooking and everyday foods, potassium from fruit, vegetables, potatoes, beans and dairy, and magnesium from wholegrains, nuts, seeds and leafy greens. If anything, most of us in the UK tend to eat more salt than we need rather than too little.

Your body is also good at holding on to what it has. Healthy kidneys adjust how much sodium and potassium you keep or pass out, which keeps levels remarkably steady even when your intake wobbles from day to day. For a 30 to 45 minute run, a strength session or a standard HIIT class, water and your next meal cover the losses comfortably. You do not need a tablet in your bottle to get through a Tuesday workout.

When do electrolytes genuinely matter?

There are real exceptions, and they are worth knowing. Electrolytes, sodium in particular, start to matter more when:

• Your session is long, roughly 60 to 90 minutes or more of continuous effort.
• It is hot or humid, so you are sweating heavily.
• You are a heavy sweater, or a salty sweater whose sweat leaves white marks and tastes noticeably salty on the skin.
• You are doing back to back sessions or racing over several hours.

In those cases you can lose a meaningful amount of sodium and fluid, and topping up helps you keep drinking effectively and feeling steady. As a rough guide, sweat contains around a gram of sodium per litre, but this varies widely from person to person, which is exactly why blanket advice falls down. Someone doing a three hour ride in summer has very different needs from someone doing a 40 minute gym session in a cool room.

Are electrolyte tablets and sports drinks worth it?

It depends entirely on the situation. For the long, hot, sweaty efforts above, an electrolyte drink or tablet is genuinely useful. The sodium helps your body absorb and hold on to the fluid you drink, and a version with some carbohydrate can help fuel the effort too. This is the scenario these products were designed for.

For a normal length workout in normal conditions, though, they are mostly marketing. Sipping an electrolyte drink at your desk or after a light gym session will not do any harm, but it is not doing much either. Your food and plain water have it covered, and the premium price does not buy you a better session, it buys convenience and flavour.

A quick word on the ingredients list. Plain water rehydrates you fine in most everyday cases. What electrolyte products mainly add is sodium, which counts when losses are high. Magnesium and potassium are often included in small amounts, and while they are important nutrients, there is little evidence that topping them up mid workout does much for someone who is otherwise well fed. Treat the bigger performance claims with healthy scepticism.

Can you drink too much water?

Yes, and this is the part the marketing rarely mentions. Drinking large amounts of plain water over a long event, more than you are actually losing, can dilute the sodium in your blood. In its serious form this is called exercise associated hyponatraemia, and it can be dangerous. It is uncommon, but it tends to affect people on long events who drink very heavily out of a fear of dehydration.

The practical takeaways here are reassuring rather than alarming. You do not need to force fluids down. On long efforts, drinking to thirst is a sensible guide for most people, and including some sodium rather than only plain water helps. In other words, in the exact situations where electrolytes matter most, they are part of drinking safely, not just of performing better.

So what should most members actually do?

Here is the simple version. Eat normally and you will cover your electrolytes most days without thinking about it. Add electrolytes when a session is genuinely long, hot and sweaty, or when you are racing for hours. Listen to your thirst rather than drinking to a rigid schedule, and do not panic buy powders for a half hour workout.

None of this replaces paying attention to how you feel. If you regularly cramp, fade badly in the heat, or feel off during long sessions, that is worth looking at properly rather than guessing at supplements.

This is the kind of detail a good plan and a coach help you get right, so it fits your sessions rather than a generic template. Edge builds a fully personalised plan across running, strength, HIIT and mobility, and with Edge Pro you can message a real coach anytime to sanity check the practical stuff, including how to fuel and hydrate for your longer efforts. With 18,000+ members training across those disciplines, the aim is to make the sensible thing the easy thing.

This article is general guidance, not medical advice. If you are new to exercise, returning from injury, pregnant, or managing a health condition, speak to your GP before starting, and see a physio for any niggle that does not settle.