Estimate sodium, potassium, and magnesium losses from sweat during exercise or heat exposure, then see how well your LMNT / Liquid IV / DIY salt-water DOES (or doesn’t) replace them. Population-average math; individual sweat rates vary 3-fold.
Your activity
1.0 L
Fluid lost
1,000 mg
Sodium lost
200 mg
Potassium lost
10 mg
Magnesium lost
1,500 mg
Chloride lost
15 mg
Calcium lost
How popular electrolyte products cover your losses
| Product (per serving) | Sodium | Potassium | Mg | Servings to replace Na loss |
|---|
Highlighted = best fit (1-2 servings replaces your calculated sodium loss). For activities under 60 min in mild weather, plain water is usually sufficient.
DIY electrolyte mix (compare to commercial products)
| Ingredient | Amount (per 500 mL water) | Provides |
|---|---|---|
| Sea salt (or table salt) | ¼ tsp (1.5 g) | ~600 mg sodium, 900 mg chloride |
| Potassium chloride (NoSalt / NuSalt) | ⅛ tsp (0.75 g) | ~400 mg potassium, ~340 mg chloride |
| Magnesium glycinate powder | 200 mg elemental Mg | ~200 mg magnesium |
| Lemon juice (optional) | 1 tbsp (15 mL) | flavor + ~25 mg potassium |
| Honey or maple syrup (optional) | 1 tsp | ~5 g carbs (~20 cal) |
Cost per serving: ~$0.10. Commercial alternatives: $1-3 per serving. The math works at any volume — scale up for a 1L water bottle by doubling.
Important caveats
- You don’t need to replace 100% during exercise. Aim for 50-75% during; restore the balance with meals after.
- Plain water is usually fine for activities under 60 min in mild weather. Electrolyte drinks are most useful for ≥90 min sessions, hot weather, or salty sweaters.
- Hyponatremia (low blood sodium) is the actual risk in endurance. Over-drinking water without sodium during long events can be dangerous. Aim for sodium intake roughly matching sweat-loss rate.
- Carbs matter for sessions over 60 min. Electrolytes without carbs is fine for short/moderate; add 30-60 g carbs/hour for endurance events.
- Daily baseline electrolyte needs are mostly met by food. Use this calculator for ACTIVITY replacement, not daily nutrition.
When to skip electrolyte drinks entirely
- Activities under 60 minutes in mild weather
- Casual walks, low-intensity yoga, gentle gardening
- If you’re on a low-sodium diet for hypertension (consult prescriber first)
- If you have kidney disease (potassium load is risky)
- If you have CHF or take potassium-sparing diuretics (potassium load is risky)
