“Electrolyte” describes a particle that carries an electric charge. In the human body, electrolytes are crucial in supporting optimal hydration. Significant electrolytes for the body are sodium, potassium, chloride, magnesium, calcium, phosphate, and bicarbonate, which can come from foods, fluids, or supplements. 

These electrolyte minerals can generate and conduct action potential in the nerves and muscles. An imbalance in these electrolytes can disrupt normal bodily functions and may lead to symptoms like headaches, fatigue, or even severe conditions. Sweat, particularly during physical exercise and exposure to hot weather, is the largest source of electrolyte and water loss. Daily water losses also occur from respiration, urination, and bowel movements. Besides hydration, electrolytes help support brain function, heart health, muscle function, and more. 

Fluid Balance 

Proper hydration is indispensable for overall health. It has been shown that a loss of body mass of over 2% due to water deficit can disrupt athletic performance, mood, attention, executive functioning, and motor coordination. Even a loss of 1% body mass can potentially impact psychological functioning and activities like driving. Water alone cannot replenish the electrolytes lost due to dehydration, and electrolyte concentration in body fluids affects the cardiovascular, endocrine, and central and autonomic nervous systems. 

Sodium is key for fluid balance as it stimulates thirst and water retention. Sodium is also the major extracellular cation that maintains extracellular fluid volume and cell membrane potential. Chloride, a predominant extracellular fluid anion, is equally as important as sodium. Fluid loss occurs in both intracellular and extracellular fluid compartments and can potentially reduce plasma volume. 

Athletic Performance 

Research has found that dehydration and electrolyte imbalances can negatively affect athletic performance. According to the American College of Sports Medicine, hydrating before, during, and after exercise is crucial in preventing dehydration (defined as more than a 2% loss in body weight due to water deficit) and electrolyte imbalances. Maintaining optimal hydration during exercise can help promote performance, mitigate heat stress, maintain plasma volume, help delay fatigue, and potentially lower injury risks associated with hydration and sweat loss. 

Replacing sweat loss through electrolyte-containing fluids is crucial for endurance athletes. The most frequent electrolyte disorder is hyponatremia (low sodium), which can result in headaches, confusion, nausea, or delirium. Exercise-induced hyponatremia has been shown to occur in a wide variety of athletes, including marathon runners, team ball sport players, recreational hikers, or those who practice yoga.  

Muscle Function and Bone Health

To maintain optimal muscle function and bone health, sodium, potassium, phosphorus, magnesium, and calcium are necessary in optimal amounts. Sodium and potassium (the major intracellular cation) are exchanged across the cell membrane as part of active transport – the sodium/potassium (Na+/K+) pump – which has a central role in muscle contraction. Potassium also plays a role in storing carbohydrates for energy in the muscles, where low potassium status may reduce energy and endurance. Magnesium is required for muscle function and proper bone strength. The electrolyte calcium is necessary for the mineralization of bones and the contraction of muscles. Additionally, around 85% of the total body phosphorus is in the bones and teeth in the form of hydroxyapatite. 

Cardiovascular Health 

A healthy Na+/K+ ratio is associated with healthy aging and reduced cardiovascular disease risk. A high Na+/K+ ratio is often associated with a diet high in processed and packaged foods and low in fruits and vegetables. Furthermore, due to sodium and chloride’s central role in extracellular fluid balance, these two minerals work together to control extracellular volume and blood pressure. 

Optimal potassium status has also been associated with helping maintain normal blood pressure. Calcium plays a role in mediating the constriction and relaxation of blood vessels – called vasoconstriction and vasodilation – and is needed for proper blood clotting. Magnesium is required for the active transport of ions like potassium and calcium across cell membranes, thus influencing the conduction of nerve impulses, muscle contraction, and normal heart function. 

Energy Production 

Magnesium is needed for adenosine triphosphate (ATP) energy production, and phosphate is a component of many metabolic intermediates, including ATP and nucleotides. An imbalanced Na+/K+ ratio can also be associated with fatigue.  

Cognitive, Mood, Neurological Health 

It is well-understood that optimal electrolyte balance can promote cognitive performance, better mood, and neurological health, as patients with electrolyte disorders often present with neurological manifestations. Suboptimal sodium status preferentially affects the central nervous system, whereas suboptimal potassium and calcium status can significantly affect neuromuscular manifestations. Calcium is needed for nerve impulse transmission and cell-signaling pathways. Magnesium is required for neurotransmitter release and may be clinically relevant to those with depression. 

Endocrine Health 

Electrolyte disturbances are associated with certain endocrine conditions, such as hypothyroidism. A significant decrease in calcium has been observed in patients with hypothyroidism and subclinical hypothyroidism, as thyroxin (thyroid hormone) normally regulates calcium ion release from the cells. Low thyroid hormones may also be associated with hyponatremia. Beyond thyroid function, low sodium also promotes the release of aldosterone, a hormone that works to maintain normal blood pressure. Plus, calcium is needed for the secretion of hormones, such as insulin.

Immune Function 

Certain electrolytes can directly support the immune system. Sodium can modulate immune cell activities. Calcium plays a role in the activation of lymphocytes. Lastly, magnesium is necessary for proper immunoglobin synthesis, macrophage response to lymphocytes, and T helper-B cell adherence. 

Summary 

Sodium, potassium, chloride, magnesium, calcium, phosphate, and bicarbonate support overall health in the human body. The role of electrolytes only begins with promoting optimal hydration, extending far beyond by helping support athletic performance, muscle and bone health, energy production, and more. 

By Danielle Moyer Male, MS, CNS, LDN