What does lack of salt do to your body? Understanding hyponatremia and its risks

October 31, 2025 •

3 min read

While excessive sodium intake is often a concern, a lack of it can pose significant health risks. In fact, severe sodium restriction can worsen insulin resistance and increase the risk of heart failure complications. So, what does lack of salt do to your body? It can lead to a dangerous electrolyte imbalance that impacts essential functions.

Quick Summary

A lack of salt can lead to hyponatremia, or low blood sodium. This imbalance causes symptoms like headaches, confusion, and muscle cramps. Severe cases can result in brain swelling, seizures, coma, and life-threatening complications.

Key Points

Hyponatremia is the result: A lack of salt leads to hyponatremia, a condition of low blood sodium that causes fluid to shift into the body's cells, including those in the brain.
Neurological symptoms are common: The brain is especially sensitive to low sodium, causing symptoms like confusion, headaches, irritability, and in severe cases, seizures and coma.
Muscle function is impaired: Sodium is crucial for muscle contractions, and low levels can lead to muscle weakness, cramps, and spasms.
Long-term metabolic issues can arise: Chronic low sodium intake has been linked to worsening insulin resistance and can increase health risks for individuals with heart failure or diabetes.
Causes are diverse: Beyond simple dietary restriction, causes can include excessive water intake, strenuous exercise, chronic diseases (heart, kidney, liver), and certain medications.
Treatment depends on the cause: Treatment ranges from fluid restriction and medication adjustments to emergency intravenous saline for severe cases, all managed under medical supervision.

The Crucial Role of Sodium

Sodium is a vital mineral that plays an essential role in numerous bodily functions. As a key electrolyte, it helps regulate the balance of fluids in and around your cells. It is also critical for proper nerve function, muscle contraction, and maintaining healthy blood pressure. The kidneys carefully control the amount of sodium in the body, retaining it when levels are low and excreting it when they are high. While the body needs some sodium to function, a severe lack of it can disrupt these crucial processes with serious consequences.

What is Hyponatremia?

Hyponatremia is the medical term for a dangerously low level of sodium in the blood, defined as a concentration below 135 milliequivalents per liter (mEq/L). This condition occurs when the ratio of water to sodium in the blood is imbalanced, causing extra water to move into your cells and make them swell. While mild cases may be asymptomatic, a sudden or significant drop in sodium levels can cause a range of symptoms, particularly affecting the brain, which is very sensitive to fluid changes.

The Symptoms of Low Sodium

The symptoms of hyponatremia can vary in severity depending on how quickly the sodium levels drop. The effects can manifest gradually in chronic cases or suddenly in acute situations.

Mild to Moderate Symptoms

Mild to moderate symptoms can include nausea, vomiting, headache, fatigue, low energy, muscle weakness, cramps, spasms, restlessness, irritability, and loss of appetite.

Severe Symptoms and Complications

Severe hyponatremia can lead to more serious and life-threatening issues such as confusion, altered mental status, seizures, coma, and dangerous brain swelling (cerebral edema). Chronic low sodium may also be linked to increased calcium excretion, potentially impacting bone health and increasing fracture risk. Furthermore, in individuals with heart failure, severe sodium restriction has been associated with worse outcomes.

Causes of Hyponatremia

Various factors and medical conditions can contribute to low blood sodium levels, including excessive water intake, certain medical conditions like heart failure or kidney disease, hormonal imbalances, some medications, severe vomiting or diarrhea, and prolonged sweating without electrolyte replacement.

How Hyponatremia Affects the Brain

The brain is particularly susceptible to changes in sodium levels. When blood sodium is low, water moves into brain cells, causing them to swell. This can disrupt normal brain function and lead to neurological symptoms ranging from mild confusion to severe and potentially irreversible damage, especially in acute cases where sodium levels drop quickly.

Managing and Preventing Low Sodium

Managing and preventing low sodium depends on its cause and severity.

Treatment Approaches

Treatment often involves fluid restriction, adjusting medications, or in severe instances, using intravenous fluids with a higher sodium concentration under medical supervision. Addressing any underlying medical conditions is also crucial.

Prevention Strategies

Preventative measures include hydrating with electrolyte-containing fluids during intense exercise, careful management of chronic conditions, avoiding excessive plain water intake in certain situations, and consulting a doctor about any concerns, especially if you have risk factors or take relevant medications.

Acute vs. Chronic Hyponatremia

It's important to distinguish between acute and chronic hyponatremia due to differences in onset, severity, and treatment considerations.


Feature	Acute Hyponatremia	Chronic Hyponatremia
Onset	Rapid (less than 48 hours)	Gradual (over days or weeks)
Sodium Levels	Drop quickly	Decrease slowly
Symptoms	Rapidly developing, often severe	Milder, more subtle
Brain Risk	High risk of dangerous swelling	Lower risk of severe swelling
Correction Risk	Requires careful, controlled correction	Less urgent correction needed

Conclusion

Understanding the risks associated with a lack of salt, or hyponatremia, is as vital as being aware of the dangers of excessive intake. Low blood sodium can disrupt crucial bodily functions and lead to symptoms ranging from mild fatigue to severe, life-threatening complications. While dietary deficiency is less common, hyponatremia is often caused by underlying medical conditions, certain medications, or excessive water consumption. Proper management and prevention require addressing the root cause and maintaining a healthy fluid and electrolyte balance. Always consult a healthcare provider if you suspect issues with your sodium levels, as expert guidance is essential for safe correction and management. For more information, visit the CDC's guidance on sodium.

Frequently Asked Questions

The initial signs of low sodium (hyponatremia) can be mild and non-specific, including a headache, fatigue, nausea, vomiting, muscle weakness, cramps, and a general feeling of low energy.

The kidneys are primarily responsible for regulating sodium levels in the body. They filter and reabsorb sodium to maintain a stable concentration, a process influenced by hormones like aldosterone and vasopressin.

Dehydration is a loss of body water, which can sometimes lead to high blood sodium (hypernatremia). Hyponatremia, however, is a condition of low blood sodium that can be caused by drinking too much water and diluting sodium levels, often without thirst.

Yes, a lack of salt can cause confusion. Low sodium levels disrupt the balance of fluids, causing brain cells to swell. This can impair brain function, leading to cognitive issues like confusion, disorientation, and lethargy.

Treatment for hyponatremia should always be guided by a doctor. For mild cases, it may involve fluid restriction and dietary adjustments, but a medical professional should determine the specific cause and treatment plan.

For those with hyponatremia, foods containing natural sodium, such as meat, fish, and dairy, are helpful. In some cases, a doctor may recommend electrolyte replacement drinks, especially after strenuous exercise.

Yes, intense or prolonged endurance exercise, such as running a marathon, can cause low sodium levels, known as exercise-associated hyponatremia. This can occur when excessive water is consumed without replacing the sodium lost through sweat.