Electrolytes are extremely important for bodily function. Your body needs them to stay hydrated before, during, and after exercise. They also support vital functions such as muscle contraction (including the heart), blood pressure regulation, nerve signaling, and more.
Electrolytes are not limited to sodium and chloride. Other important electrolytes include magnesium, potassium, and calcium.
How electrolytes work in the body
The body uses electrolytes to balance electrical charges that flow between and around cells, including those in the bloodstream, brain, and muscles.
In the body, these substances act as ions. Key processes such as muscle contractions, fluid balance, and nerve impulse transmission are all supported by electrolytes.
When the body loses water due to sweating, the concentration of electrolytes—mainly sodium ions (Na+)—around cells increases, disrupting the balance of ions on each side of the cell membrane. In response, the body excretes more sodium through sweat to restore balance.
When the body becomes overhydrated, the opposite occurs: electrolyte concentration around cells becomes too low, also disrupting balance. To restore ion concentration, the body increases sweating during exercise to reduce excess water.
In both cases, imbalance across the cell membrane can reduce cellular function and negatively affect performance.
Electrolyte deficiency in the body
A lack of these minerals can lead to a wide range of symptoms, depending on which electrolyte is deficient. Symptoms may include muscle cramps or weakness, headaches, dizziness, or irregular heartbeat.
The kidneys store electrolytes for future use by filtering the bloodstream and ensuring that no unnecessary electrolytes are lost.
In most cases, the body receives sufficient electrolytes through a balanced diet. Severe or sudden deficiencies are relatively rare because the body tightly regulates electrolyte balance.
Electrolytes and exercise
Electrolytes are primarily lost through sweat and muscle contractions during exercise. Fluid loss in athletes can range from 1 to 3 liters per hour depending on environment, intensity, duration, genetics, and clothing. That is why hydration before, during, and after exercise is essential.
Functions of each electrolyte
Magnesium
Magnesium is an intracellular cation involved in ATP metabolism, proper muscle function, nerve function, and neurotransmitter release.
Sodium
Sodium is an osmotically active cation and a key electrolyte in extracellular fluid. It helps maintain extracellular fluid volume and regulates cell membrane potential. Sodium and potassium are exchanged across cell membranes as part of active transport. Sodium regulation occurs in the kidneys. Sodium deficiency can cause hyponatremia, leading to symptoms such as headaches, confusion, nausea, and delirium.
Calcium
Calcium plays an important physiological role in bone mineralization, muscle contraction, nerve impulse transmission, blood clotting, and hormone secretion.
Potassium
Potassium is mainly an intracellular ion required by all body tissues. It helps maintain proper fluid balance inside cells and supports muscle contraction and blood pressure regulation. Potassium imbalances may lead to cardiac arrhythmia.
Sources of electrolytes
Sodium and chloride are present in most meals and are generally not a concern.
Magnesium sources:
Beans, beef, peanut butter, almonds, peanuts, cashews, pumpkin seeds, soy and soy milk, spinach, brown rice, oatmeal, salmon, bananas, raisins, dark chocolate (at least 70%), milk and yogurt.
Potassium sources:
Dried fruits, beans, lentils, potatoes, squash, spinach, broccoli, avocado, banana, melon, oranges and orange juice, coconut water, tomatoes, dairy and plant-based milk (soy, almond), yogurt, cashews and almonds, chicken, salmon.
Calcium sources:
Dairy products and fortified plant-based milks (almond, soy), cheese, yogurt, salmon (with bones), almonds, leafy greens (turnip greens, kale, spinach).
The priority should always be obtaining these nutrients through a healthy diet. However, if you cannot meet your needs through food, sports drinks and supplements may be used.
Keep in mind that excessive intake of these minerals can cause side effects. Avoid excessive consumption of processed and salty foods.