💧 Electrolyte basics
What are electrolytes and why do they matter?
Electrolytes are minerals that carry an electrical charge in your body.
The big ones for daily function and performance are sodium, potassium, and magnesium
(plus calcium and chloride). They help regulate:
- Fluid balance: how much water stays in your bloodstream vs leaves into tissues
- Nerve signaling: brain + nerve function
- Muscle contraction: including cramps and strength output
- Blood pressure: especially sodium/potassium balance
Most days, a normal diet handles this automatically. Electrolyte problems show up when
you sweat heavily, train in heat, fast, have GI illness (vomiting/diarrhea), or run low-carb/keto
(which increases sodium loss early on). That’s why electrolyte advice feels confusing: some people
need more salt, while others must be careful with sodium.
If you have kidney disease, heart failure, uncontrolled hypertension, or take diuretics, consult a clinician before changing sodium intake.
🧮 How this calculator works
Targets = baseline + sweat replacement
The calculator produces two parts:
(1) a daily baseline target and
(2) a workout add-on based on sweat loss.
The goal is not perfect precision; it’s a practical plan you can follow.
Step 1: Estimate sweat loss
Sweat loss is approximated as:
liters lost = sweatRate(L/hr) × workoutHours.
If you don’t know your sweat rate, a common starting assumption is 0.7–1.0 L/hr,
but it varies a lot.
Step 2: Convert sweat loss into sodium needs
Sweat sodium concentration varies widely, but a practical mid-range assumption is roughly
~800 mg sodium per liter of sweat. Some people lose much more; some less.
This tool uses a conservative assumption and adjusts slightly for heat and symptoms.
Step 3: Add potassium + magnesium guidance
Potassium is usually best from food (fruits, potatoes, beans, leafy greens).
Magnesium supports muscle and sleep; many people run low. The calculator gives a gentle target
and points you to food sources.
Why salt grams?
Labels and advice often talk about “salt” (NaCl) not sodium. Table salt is ~39% sodium.
So:
salt grams ≈ sodium mg ÷ 390.
Example: 1000 mg sodium ≈ 2.6 g salt.