Electrolytes for Runners UK - What You Actually Need
Electrolytes for runners UK - what you actually need
Running is one of the most demanding activities for electrolyte balance. Sweat losses during a moderate run contain significant amounts of sodium, potassium, magnesium and chloride — and replacing fluid with plain water alone can actually make things worse by diluting the electrolytes that remain. Here is exactly what runners need, when and how much.
Why electrolytes matter so much for runners
Electrolytes are minerals that carry an electrical charge and regulate the most fundamental physiological processes - fluid balance between cells, nerve impulse transmission, muscle contraction and energy production. When runners sweat, they lose electrolytes rapidly. The consequences of electrolyte depletion during running include muscle cramps, fatigue, reduced performance, dizziness, nausea and - in serious cases - hyponatraemia (dangerously low sodium caused by drinking large amounts of plain water during prolonged exercise).
This is why professional marathon and endurance runners always use electrolyte supplements rather than just water - the science on this has been settled for decades.
Which electrolytes do runners lose?
Sodium - the most critical for runners
Sodium is the primary electrolyte in sweat and the most significant loss during running. It regulates blood volume and fluid balance. Sodium depletion causes performance decline and is the driver of exercise-associated hyponatraemia in endurance runners who drink only water. The body cannot retain fluid effectively without adequate sodium.
Potassium
Potassium works with sodium to regulate fluid balance and is essential for muscle contraction. Potassium depletion contributes to muscle cramps and fatigue during and after running. Lost in moderate amounts through sweat.
Magnesium
Magnesium is essential for muscle relaxation after contraction and for energy production in muscle cells. Deficiency is associated with cramps, particularly nocturnal leg cramps common in runners. Lost through sweat and also depleted by the physical stress of training.
Chloride
The primary anion in sweat, chloride works alongside sodium to maintain fluid balance. Lost in proportion to sodium during running.
When should runners take electrolytes?
- Before a run over 45 minutes: pre-loading with electrolytes ensures optimal fluid balance at the start
- During a run over 60 minutes: sipping electrolyte solution rather than plain water prevents sodium dilution
- After every run: post-run electrolyte replacement accelerates recovery and reduces next-day fatigue and soreness
- Daily for regular runners: daily electrolyte supplementation maintains baseline levels and prevents cumulative depletion
The Jenni Falconer connection
Kollo Health was co-founded by Jenni Falconer - ten-time London Marathon runner, Smooth Radio breakfast host and host of the RunPod podcast. Kollo Electrolytes+ was developed to support her own running recovery and daily energy management as a regular marathon runner with an extremely demanding schedule. Read more on the Jenni Falconer page.
Kollo Electrolytes+ delivers sodium, potassium, magnesium and B vitamins in a convenient daily sachet - sugar-free, naturally flavoured and designed for consistent daily use rather than just race-day recovery.
Kollo Health was co-founded by Jenni Falconer - TV presenter, Smooth Radio breakfast host, ten-time London Marathon runner and host of the RunPod podcast. Read her story and why she created Kollo.
