Do you need electrolyte tablets, or is water enough?
For workouts under an hour, plain water and your regular diet already cover your electrolyte losses; past that — especially in heat or with heavy, salty sweat — the math changes and tabs start to earn their place.
How much sodium you actually need mid-workout depends more on you than on the workout itself. Sweat sodium concentration varies almost tenfold between individuals — roughly 10 to 90 mmol per liter — shaped by genetics, heat acclimation, diet, and fitness level, not just how hard you’re pushing. That’s why one person finishes a hard session with white salt lines crusted on their shirt while the next person barely notices a difference.
Duration matters more than the electrolyte content itself. ACSM’s position stand on fluid replacement draws the practical line at about an hour: below that, plain water performs just as well as any electrolyte drink for almost everyone, because you haven’t lost enough sodium (typically a few hundred milligrams) for your next meal to fail to cover it. Past that mark — especially in heat, humidity, or long heavy-sweat sessions — real deficits build, and that’s the window where supplementation has a mechanism behind it.
But sodium mattering over long exercise and electrolyte tabs boosting performance are two different claims, and the second is shakier than marketing implies. A systematic review of controlled trials testing sodium supplementation on its own found almost no measurable performance benefit — four of five studies showed nothing. What tends to move outcomes is sodium paired with carbohydrate: a 2026 meta-analysis of 26 trials found carb-electrolyte drinks improved time-to-exhaustion and blood glucose versus placebo, but had no significant effect on real finishing time over a set distance.
The overcorrection risk
More isn’t automatically better. Exercise-associated hyponatremia — dangerously low blood sodium — is driven far more by drinking too much fluid than by too little sodium. The 2017 consensus update on the condition is blunt: sodium-containing drinks will not prevent it in someone who is simply overdrinking. For most recreational exercisers, the realistic failure mode isn’t under-supplementing electrolytes; it’s treating a 45-minute gym session like an ultramarathon.
Where tabs actually fit
Save electrolyte tabs for sessions past 60-90 minutes, hot or humid conditions, or when you already know from experience you’re a heavy, salty sweater. For anything shorter, water plus normal meals already supplies the sodium, potassium, and magnesium you’re losing — those minerals are abundant in ordinary food and aren’t meaningfully depleted by a short workout. Going long, the combination that actually seems to help is electrolytes alongside some carbohydrate, not sodium by itself.