Electrolytes and Performance: Beyond the Sports-Drink Marketing
I cramped through a hot summer of training and assumed I needed more water. I needed more sodium. Here is what electrolytes actually do, who needs them, and who is being sold colored sugar water.
Electrolytes and Performance: Beyond the Sports-Drink Marketing
One brutal July I kept cramping mid-workout and feeling lightheaded between sets despite drinking what felt like gallons of water. The fix wasn't more water — it was sodium. I'd been diluting myself. That summer sent me into the electrolyte literature, and the short version is: electrolytes matter a lot in specific situations and almost not at all in others, and the sports-drink industry profits from blurring the line.
What electrolytes actually do
Electrolytes — primarily sodium, potassium, magnesium, and chloride — are minerals that carry electrical charge and govern fluid balance, nerve signaling, and muscle contraction. Sodium is the big one for athletes: it's the primary electrolyte lost in sweat and the main driver of how well you retain the fluid you drink. Drinking lots of plain water while sweating heavily can actually lower your blood sodium (hyponatremia), which causes the exact cramping and fogginess I was experiencing.
Who actually needs to supplement
Be honest about which bucket you're in:
- Probably need extra electrolytes: heavy sweaters, people training 60+ minutes in heat, those doing two-a-days, anyone on a low-carb diet (which flushes sodium and water), and salty sweaters (white crust on your shirt is a tell).
- Probably don't: someone doing a 45-minute air-conditioned lifting session who eats a normal diet. You get plenty of electrolytes from food, and a regular meal afterward replaces what you lost.
The cramping myth (partial)
Cramping is more complicated than "low electrolytes" — the neuromuscular-fatigue theory (Schwellnus) explains a lot of exercise cramps better than dehydration does. But for prolonged, hot, high-sweat sessions, sodium genuinely helps with fluid retention and the lightheaded/cramp cluster. For a short indoor lift, your cramp is more likely fatigue or technique than a mineral deficit.
Cutting through the marketing
The dirty secret of most sports drinks: they're mostly sugar with a modest sodium dose. That's fine during prolonged endurance work, where you want the carbs too — but it's a terrible everyday drink. If you want electrolytes without the sugar, look for a mix with a meaningful sodium dose (500-1000mg) and skip the ones selling 50mg of sodium alongside 30g of sugar and a wellness aesthetic.
How to apply this
If you train short and indoors and eat normally: just salt your food and drink to thirst — you're fine. If you train long, hot, sweaty, or low-carb: add ~500-1000mg of sodium (plus some potassium and magnesium) to your water for sessions over an hour, and don't over-drink plain water on heavy-sweat days. Match your fluid and sodium to how much you actually sweat, not to a marketing slogan.