Electrolyte Loss Calculator

Understanding Sweat Composition

Sweat is not "just water." It's a precise cocktail of electrolytes essential for nerve firing and muscle contraction. Losing too much without replacement leads to "cramping," "bonking," and cardiac drift.

The Big 4: What Are You Losing?

1. Sodium (Na+)**: The MAIN driver. Sweat is salty. Range: **400-2000mg per liter. 2. Chloride (Cl-): Typically mirrors sodium loss. 3. Potassium (K+): Minor loss (~200mg/L). Found in cells, less critical to replace acutely. 4. Magnesium (Mg2+): Very minor loss (~20mg/L). Cramps are usually due to sodium or fatigue, not magnesium.

💧 Electrolyte Loss in Sweat (per Liter)

| Electrolyte | Average Loss | Low Range | High Range (Salty Sweater) | | :--- | :--- | :--- | :--- | | Sodium (Na+)** | **1000 mg | 400 mg | 2000 mg | | Chloride (Cl-)** | **900 mg | 350 mg | 1700 mg | | Potassium (K+)** | **200 mg | 150 mg | 300 mg | | Magnesium** | **20 mg | 10 mg | 30 mg |

⚠️ The Danger: Hyponatremia (Water Intoxication)

Drinking plain water during an ultra-event (>4 hours) without sodium dilutes your blood sodium levels. * Symptoms: Headache, bloating, confusion, seizure. * Rule: If you crave salt, eat salt. If you slosh when you run, stop drinking.

💧 Hydration Protocol

Pre-Loading (Before)

Drink 500ml** with **500mg Sodium 60-90 minutes before the event to expand plasma volume.

Maintenance (During)

* < 60 Mins: Water is fine. * 60-120 Mins: 100-200 calories (carbs) + 300mg Sodium. * > 2 Hours: 500-800mg Sodium per liter of fluid.

Recovery (After)

Weigh yourself. For every 1lb (0.45kg)** lost, drink **20-24oz of fluid with electrolytes.