Electrolytes for Runners: A Complete Pre, During, and Post-Run Strategy
Stop guessing about hydration. Learn the evidence-based approach to electrolyte timing and dosing for runners of all distances.
Why Runners Lose Electrolytes So Fast
Running is one of the most electrolyte-intensive activities you can do. A typical runner loses between 500mg and 1,500mg of sodium per hour through sweat alone, along with significant amounts of potassium, magnesium, and calcium. In hot weather or during intense efforts, these losses can double. The American College of Sports Medicine recommends replacing approximately 500-700mg of sodium per liter of fluid lost during exercise. However, sweat rates vary enormously between individuals — some people are salty sweaters who lose up to 3 times more sodium than average. Not replacing these losses leads to impaired performance, muscle cramps, and in severe cases, hyponatremia (dangerously low blood sodium).
Pre-Run Hydration: The Foundation
Your pre-run hydration strategy should begin 2-4 hours before your run. Start by drinking 16-20 ounces of water with 500-1,000mg of sodium. This pre-hydration primes your body with the fluid and sodium it needs to maintain blood volume during exercise. Avoid overhydrating with plain water, which can dilute your sodium levels before you even start. If you're a heavy sweater or running in heat, consider adding an electrolyte supplement to your pre-run routine. Some runners also benefit from 200-400mg of sodium 15-30 minutes before starting, especially for morning runs when you haven't consumed much food or fluid yet.
During the Run: Replacement Strategy
For runs under 60 minutes, water alone is usually sufficient for most runners. For runs lasting 60-90 minutes, aim to consume 200-500mg of sodium per hour along with 16-24 ounces of fluid. For runs exceeding 90 minutes, increase to 500-1,000mg of sodium per hour, plus 100-200mg of potassium and 50-100mg of magnesium. LMNT stick packs are excellent for mid-run hydration because they're portable, pre-measured, and dissolve quickly in water bottles. Nuun tablets are another convenient option that eliminate the need for powder mixing. The key principle is to drink to thirst rather than following rigid schedules — your body's thirst mechanism is remarkably accurate when it hasn't been dulled by chronic overhydration.
Post-Run Recovery
After your run, you need to replace everything you lost plus a bit more. A good rule of thumb is to consume 150% of the fluid you lost (weigh yourself before and after to calculate). For electrolytes, aim for 1,000-1,500mg of sodium within the first hour post-run, along with potassium and magnesium. Dr. Berg's Electrolyte Powder is excellent for post-run recovery because it provides 1,000mg of potassium per serving — the highest of any product we tested — along with comprehensive mineral coverage. Pair your electrolyte drink with a meal or snack containing both protein and carbohydrates within 30-60 minutes to maximize recovery and glycogen replenishment.