What Causes Low Sodium Levels?

Low blood sodium levels indicate hyponatremia, which is generally defined as a serum sodium concentration below 135 mmol/L. Hyponatremia is a common electrolyte disorder encountered in clinical practice. So, what causes low sodium levels? Below is an explanation.

Causes of Low Sodium Levels

1. Reduced Intake

This scenario most commonly occurs in patients with poor dietary intake. Such individuals may benefit from increasing consumption of salt-rich foods and receiving intravenous sodium supplementation. Maintaining balanced nutrition is essential in daily life, and spicy or irritating foods should be avoided.

2. Excessive Loss

Excessive sodium loss can occur via two primary routes. First, renal losses—seen in patients taking diuretics or those with adrenal insufficiency and glucocorticoid deficiency. Second, gastrointestinal losses—commonly observed in patients experiencing nausea, vomiting, or diarrhea. Severely low sodium levels may precipitate hypotonic encephalopathy, leading to altered mental status or even coma.

3. Excessive Sweating

Individuals engaging in intense physical activity experience substantial sweating, resulting in significant sodium loss through sweat. Therefore, appropriate hydration during exercise—and consumption of sports drinks or diluted saline solutions afterward—is recommended. Similarly, people working regularly in high-temperature environments lose large amounts of sodium due to profuse sweating, potentially disrupting sodium homeostasis.

Additional Information: Risks Associated with Low Sodium Levels             

1. Low serum sodium reduces plasma osmolality. In a hypotonic state, patients are prone to develop hypotonic edema—particularly cerebral edema—manifesting as dizziness, headache, poor appetite, nausea, vomiting, fatigue, and lethargy.

2. In severe hyponatremia (serum sodium < 110 mmol/L), symptoms may include confusion, disorientation, delirium, lethargy, herniation of the brain, coma, agitation, seizures, and epileptic episodes—all life-threatening conditions posing serious health risks.

The above outlines the main causes of low sodium levels. We hope this information is helpful to you.