Electrolyte drinks for runners: essential or overrated?
You come back from a hot afternoon 10-miler, legs twitching, head a little foggy, and the orange-flavoured tub on your kitchen counter suddenly looks like the obvious answer.
Most of the runners we work with reach for electrolyte products without thinking twice — and the running shop seems to agree, with carb powders, salt capsules, "electrolyte-only" tabs and concentrates stacked alongside gels. It's easy to feel behind if you're just carrying a water bottle.
Here's the calmer version of the story. Most runners don't need an electrolyte drink on most of their runs. The genuine physiological cases where one earns its place are narrower and more specific than the marketing suggests, and the science has been quietly consistent on this for decades. Once we walk through what's actually happening in your body on an easy hour versus a hot half marathon, the decision becomes much less about brands and much more about the run in front of you.
Why an easy hour doesn't need anything fancy
If your session is going to sit under roughly an hour — easy recovery jog, an out-and-back tempo, a group run that fits inside a lunch break — the balance of evidence says plain water does the job. The American College of Sports Medicine position stand from the mid-1990s still holds, and subsequent updates haven't moved it: there's little physiological or performance difference between water and a carbohydrate-electrolyte drink for exercise under an hour.
That might feel surprising given how the products are marketed, but the volume of fluid lost on a 50-minute easy run in mild weather is modest, the body has well-developed mechanisms for handling it, and a normal meal in the next couple of hours restores whatever small electrolyte debt you've built. Adding a sugary drink on top often means calories you didn't need, plus a level of sweetness that, for some runners, sits uneasily in the gut during movement.
What we tend to look for instead, in the runners we coach, is the baseline habit: arrive hydrated, drink to thirst on shorter sessions, eat a normal breakfast or a sensible post-run meal. That's it. No extra equipment, no special recipes, no performance penalty. The runners who end up overcomplicating things are usually the ones who've internalised the marketing before they've internalised the physiology.
A sports drink won't outperform water on an easy hour. The research has been saying so for almost thirty years, and that part of the conversation rarely makes it onto the tub.
When the equation shifts: longer efforts, more sweat, more heat
The story changes once we cross into longer territory, especially in heat, where sweat losses climb and the body's carbohydrate stores start to matter. This is the zone where a carbohydrate-electrolyte drink — note both halves of that name — earns its keep.
For sustained intense exercise beyond an hour, consensus guidance points to around 30 to 60 grams of carbohydrate per hour, which a well-formulated 4 to 8 percent drink can deliver in roughly 600 to 1,200 mL of fluid per hour, depending on concentration and how much your gut tolerates. For events lasting between one and two and a half hours, that 30 to 60 gram figure is the in-race target. For marathons and ultras past two and a half hours, the guidance allows up to 90 grams of carbohydrate per hour — provided you've trained the gut to handle it, and you won't find that out for the first time on race day.
The Australian Institute of Sport frames the formulation side of this in a useful way. A sports drink at 4 to 8 grams of carbohydrate per 100 mL and 10 to 30 mmol/L of sodium — roughly 23 to 69 mg per 100 mL — is essentially a compromise: enough carbs to fuel working muscle, enough sodium to keep fluid moving through the gut and into the bloodstream, all in a solution the stomach tolerates without sloshing. That's why electrolytes and carbohydrates belong in the same drink for sustained effort. They are doing two related jobs.
For the recreational marathoner on a warm day, the bigger lever is usually fluid volume and carb timing, not a magic mineral blend. A sodium-only tablet doesn't replace the fuel piece; a carb gel without fluid doesn't solve the dehydration piece. The drinks that actually work in this zone are doing three things at once — replacing fluid, topping up glycogen, and keeping the sodium-fluid balance moving — and skipping any one of those three tends to show up in the last third of the race.
The cramp myth: what sodium actually does — and doesn't
Let's talk about the calf that tightens on mile 22 of a long run, or the quad that twitches in the last kilometre of a hot half. Most runners we see reach the same conclusion: salt depletion, electrolyte shortage, reach for the salt. The sports-drink industry is built on this association. It's also more complicated than that.
Cramps, the better guidance says, have multiple contributors, and muscle fatigue is among the most consistent — not salt loss in isolation. The research doesn't support the simple equation of salty sweat equals guaranteed cramping, and it doesn't show that drinking electrolytes reliably prevents cramps from happening. What it does show is that cramping tends to cluster at the end of long efforts, when the muscle is tired and the nervous system is sending unusual signals — not necessarily when the body is chemically depleted.
That doesn't make sodium irrelevant. Sodium helps the body retain the fluid you drink, supports normal nerve and muscle function, and is part of why electrolyte drinks work in longer events for reasons that have nothing to do with cramp prevention. But reaching for a high-sodium capsule every time a muscle twinges is a bit like popping a painkiller before you've checked what's actually going on.
| What it feels like | What it more often means |
|---|---|
| Twitching or cramping in the last miles of a long effort | Accumulated muscle fatigue; a pace reduction, brief stretching and slowing down usually help |
| Heavy sweating with visible salt streaks on kit | A nudge to investigate — but visible streaks alone can't reliably tell you your sweat sodium concentration or your personal sodium needs |
| Dizzy, foggy, with weight gain on a slow run | Likely overdrinking relative to sweat loss — a different problem (see below) |
The table is a simplification, but the underlying point isn't. A twitch is information about the muscle's state, and the answer isn't always minerals. Listening to the muscle usually means reading the broader context, not reaching for the salt. And the same goes for salty-looking kit: it might prompt a closer look at how much sodium you're losing, but it isn't diagnostic on its own. Runners with low sweat sodium can show visible streaks; runners with high sweat sodium can show almost none. The only honest answer comes from actually testing, not from eyeballing a cap or a collar.
The underappreciated risk: drinking too much
If the cramp story is overcooked in popular running culture, the hydration story has its own blind spot — and it's the one we think deserves more attention than it usually gets.
Exercise-associated hyponatremia is defined as blood sodium dropping below 135 mmol/L during or within 24 hours after prolonged physical activity. The word matters here: it's not about losing sodium, but about having too little sodium in your blood relative to the fluid in your body. The most common cause, in the consensus guidance, is drinking too much fluid — too much plain water, or too much of any hypotonic drink — without matching sodium intake to losses.
This is the part the marketing tends to skip. A sodium-containing sports drink cannot prevent hyponatremia if you're overdrinking. It lowers the risk compared to plain water in some scenarios, but it doesn't undo the fundamental problem of fluid volume outrunning sodium balance. Runners at slower paces on long events — the marathoner enjoying the day, the four-hour half-marathoner, anyone drinking at every aid station "just in case" — are statistically more exposed than the fast finisher who simply loses more in sweat. The slower you go, the less fluid you lose per hour, and the more likely it is that drinking aggressively will outpace your losses.
The practical lesson is gentle and important: drink to a plan, not to anxiety. If you're several hours into a long effort and your body weight is meaningfully higher than it was at the start, that's information. If your urine is clear and copious throughout a long race, that's also information. Neither extreme is good. The body has thirst for a reason, and on most long runs that signal is more trustworthy than the crowd at the aid station handing you cups.
Building a plan that fits the run in front of you
So where does that leave the recreational runner staring at the wall of options? Somewhere more individualised than the labels suggest, and probably less anxious than the marketing implies. Here's how we'd walk through it with an athlete sitting in front of us.
Start with the run itself. Duration, intensity, weather, access to fluids, and how much you've trained the gut to handle carbohydrate — these all matter more than the brand on the packet. An easy 45-minute shake-out the day before a race isn't the same problem as a 50-kilometre weekend in late July, and it shouldn't get the same plan.
Test in training, not in race. Whatever you plan to drink for 26.2 miles, you've already practised in shorter efforts. The gut is trainable; race day is not the place to find out you tolerate 90 grams of carbohydrate an hour, or that your stomach doesn't agree with a particular sweetener. Build up gradually across weeks of long runs, and treat any gut reaction as data, not failure.
Know your sweat rate — and ideally your sweat sodium. A simple body-weight check before and after a representative run, in conditions similar to your goal event, gives you a litres-per-hour figure that no product can replace. If you want to go further, sweat-sodium test strips or laboratory assessment can tell you whether you lose more or less salt than average. That then sharpens whether the rough 500 to 700 mg sodium per litre range often suggested during exercise is too low, too high, or about right for you. That range is a reference point, not an instruction — there isn't consensus on a single optimal in-run sodium target, and pretending there is would mislead you.
Match the format to the job. A carb-electrolyte drink is genuinely useful for sustained efforts where fluid, fuel and sodium are all relevant. For shorter recovery runs or cool-weather sessions, plain water plus a normal meal often does more for you. Electrolyte-only tablets sit in an interesting middle ground — useful when you're carrying your own fluid and just need to top up sodium on a long effort, less useful on a quick session where water does the job. None of these is universally the answer. The format follows the run, not the other way around.
The decision isn't water versus electrolyte drink. It's about what your specific run is asking of you, and what your specific body tends to lose.
Where we'd land
If we had to summarise how we'd advise the runners who ask us about electrolyte drinks most often, it would be something like this. Trust water for the runs under an hour. Build a real plan around carbohydrate-electrolyte drinks for efforts above that, especially in heat. Don't let the branding crowd out the basics — and the basics are individual sweat rate, gut training, a sensible recovery meal, and not overdrinking in the first place.
An electrolyte drink isn't a magic insurance policy, and it isn't a marketing scam. It's a tool with a real use case — a narrow one for some athletes, a regular feature for others, and a totally unnecessary purchase for many. Once you've worked out which kind of runner you are on which kind of run, the wall of products at the running store stops looking quite so intimidating. And the answer you arrive at will be a more honest one than any of us can hand you in a packet.