Electrolyte Supplements: Who Actually Needs Them (And Who's Wasting Money)

Electrolyte packets are everywhere now. For most people doing a normal workout, they're unnecessary. For a specific group of athletes, they can genuinely prevent a dangerous problem.

Electrolyte packets went from a niche endurance-athlete product to something everyone tosses in a water bottle before a 45-minute gym session. The marketing implies you're constantly on the edge of dehydration and deficiency. For most people, that's not true. For a smaller group, electrolytes matter more than almost anything else in their nutrition plan. The trick is knowing which group you're in.

Sweat sodium loss is wildly individual

Research on sweat composition, including work from Lindsay Baker and colleagues measuring sweat sodium across large athlete populations, has found sodium concentration in sweat ranges from around 200 mg to over 2,000 mg per liter between individuals — a tenfold difference. Two people doing the identical workout in identical heat can have completely different sodium losses. That variability is exactly why there's no single electrolyte recommendation that applies to everyone.

When plain water is genuinely enough

For most gym sessions under an hour at moderate intensity, you are not losing enough sodium and fluid to meaningfully affect performance, and a normal diet — which for most people already includes more sodium than needed — easily replaces what you sweat out. Buying an electrolyte packet for a 45-minute lifting session is, for the average person, paying for reassurance rather than a physiological need.

When electrolytes genuinely matter

• –Endurance events over 90 minutes to 2+ hours, especially in heat — sodium losses accumulate meaningfully over that duration.
• –Heavy sweaters — you've probably heard that white salt streaks on your shirt mean you're a salty sweater. It's a reasonable hunch, and it's also not validated: dry air leaves more visible residue at the exact same sodium concentration, and so does simply sweating a lot. Treat the shirt as a hint, not a diagnosis. If you actually want to know, get a sweat test.
• –Multiple training sessions in a single day, or back-to-back training days in the heat, where total daily sodium loss adds up.
• –Long endurance events specifically, where proper electrolyte and fluid balance reduces cramping and bonking risk.

The overcorrection nobody talks about: hyponatremia

There's a real risk on the other end of this that gets far less attention than dehydration: exercise-associated hyponatremia, where blood sodium becomes dangerously diluted from drinking too much plain water during long events. Almond and colleagues, in the New England Journal of Medicine in 2005, drew blood at the finish line from 488 runners at the Boston Marathon. Thirteen percent came in with a blood sodium of 135 or below, and three were under 120 — the range where people end up in an ambulance. Those were mostly recreational runners who volunteered for the study rather than the whole field, so don't read it as one in eight marathoners. Read it as: common enough that it isn't rare.

The bottom line

If your training is under an hour, water and a normal diet already cover your electrolyte needs — save your money. If you're a heavy sweater, training for 90-plus minutes, or stacking sessions in the heat, targeted sodium replacement is a legitimate tool, not marketing. And if you're doing long endurance events, pay as much attention to not overdrinking plain water as you do to staying hydrated — the dangerous mistake usually runs in that direction, not the one everyone assumes.