Electrolytes are minerals that carry an electric charge when dissolved in fluids. They are essential to virtually every function that keeps cells alive — from maintaining fluid balance to enabling muscle contractions and transmitting nerve signals. Yet they are among the most commonly depleted nutrients, particularly in active individuals and those living in hot climates.
Contents
What are electrolytes?
The main electrolytes in the human body are sodium, potassium, magnesium, calcium, chloride, phosphate, and bicarbonate. Each plays a distinct role, and they work in balance with one another — which is why electrolyte formulas designed to replenish multiple minerals at once are generally more effective than single-mineral supplements for hydration purposes.
Why electrolytes matter for hydration
Water alone does not hydrate you efficiently. Electrolytes — particularly sodium and potassium — govern osmosis, the process by which water moves into and out of cells. Without adequate electrolytes, water consumed passes through the body without being properly absorbed into tissues.
This explains why drinking large amounts of plain water during or after heavy exercise can dilute electrolytes further, potentially causing a condition called hyponatraemia (low blood sodium), which causes headaches, nausea, and in severe cases, confusion.
Electrolytes and energy
Magnesium is the electrolyte most directly involved in energy production. It is a required cofactor for ATP synthesis — the biochemical process that generates cellular energy. Low magnesium is one of the most common nutritional causes of persistent fatigue and muscle weakness in the UK.
Potassium and sodium maintain the electrochemical gradients that allow nerve impulses to fire rapidly and muscles to contract and relax efficiently. Imbalances here manifest as fatigue, sluggishness, and difficulty sustaining effort during exercise.
Electrolytes and muscle function
Muscle cramps — particularly those occurring at night or during exercise — are a classic sign of electrolyte depletion. Calcium and magnesium regulate muscle contraction and relaxation respectively. When these are out of balance, muscles can spasm involuntarily.
For athletes and regular gym-goers, maintaining electrolyte balance is as important as protein intake for performance and recovery. Delayed onset muscle soreness (DOMS) is worsened by electrolyte depletion, and recovery is slower when minerals lost through sweat are not replaced.
Who is at risk of electrolyte imbalance?
- Athletes and active people — sweat contains significant amounts of sodium, potassium, and magnesium. Training without replacing these minerals progressively depletes stores.
- People in hot weather — even without exercise, sweating in summer or during travel to warm climates depletes electrolytes rapidly.
- Those following low-carbohydrate or ketogenic diets — carbohydrate restriction causes increased kidney excretion of sodium and potassium, making supplementation particularly important.
- Anyone experiencing illness with vomiting or diarrhoea — gastrointestinal losses are the fastest route to acute electrolyte depletion.
- Older adults — kidney function declines with age, affecting electrolyte regulation, and thirst perception diminishes, reducing fluid and mineral intake.
Signs of electrolyte depletion
- Muscle cramps, particularly at night or during exercise
- Persistent fatigue despite adequate sleep
- Headaches
- Dizziness when standing
- Heart palpitations
- Constipation
- Difficulty concentrating
How to maintain healthy electrolyte levels
Dietary sources
A varied whole-food diet provides a reasonable baseline of electrolytes. Good sources include:
- Sodium: whole foods naturally contain sodium; in the UK, dietary sodium is rarely deficient without specific circumstances
- Potassium: bananas, avocado, sweet potatoes, leafy greens, beans
- Magnesium: nuts, seeds, dark chocolate, whole grains, legumes
- Calcium: dairy, fortified plant milks, sardines, broccoli
Supplementation
For those with increased needs — active individuals, keto dieters, or anyone experiencing depletion symptoms — a balanced electrolyte formula covering sodium, potassium, and magnesium provides reliable, convenient replenishment. Look for formulas without added sugar, as glucose-loaded sports drinks are designed for endurance athletes and unnecessary for most people.
Hydration strategy
Rather than drinking large amounts of plain water at once, spreading fluid intake throughout the day — and including electrolytes with larger volumes of water — supports better absorption and cellular hydration.
Related reading
- Best Magnesium Supplement UK 2025
- Chronic Fatigue: Causes, Symptoms & How to Recover Energy
- Best Vitamin B12 Supplement UK 2025
BestElectrolytes
£37.8
View Product →