Even Normal Sodium Levels Linked to Heart Failure

A major new study from Bar-Ilan University has uncovered a surprising link between higher sodium levels and serious heart conditions, even when those levels are still considered “normal.” People with sodium at the upper end of the normal range were found to be significantly more likely to develop high blood pressure and heart failure, two of the most common chronic diseases as we age. The findings were published in the European Journal of Preventive Cardiology.

The research examined electronic health records spanning 20 years, from 2003 to 2023, covering more than 407,000 healthy adults who receive care through Leumit Healthcare Services, one of Israel’s top health providers. It is one of the largest and most detailed studies ever to explore how hydration levels may impact long-term heart health.

Among the key findings:

Sodium levels of 140–142 mmol/L (still within normal range) were linked to a 13% higher risk of hypertension.

Levels above 143 mmol/L were associated with a 29% higher hypertension risk and 20% higher risk of heart failure

Nearly 60% of the healthy adult population had sodium levels in these risk-associated ranges

Sodium, which is routinely tested in standard blood tests, has long been considered normal within the 135–146 mmol/L range. But this study challenges that assumption, suggesting a strong, long-term association between higher sodium levels and cardiovascular risk, even among those considered otherwise healthy.

These associations remained strong even after adjusting for age, sex, BMI, blood pressure, smoking, and potassium levels. The analysis excluded individuals with conditions that affect water balance to ensure a more accurate reflection of hydration-related risk.

“Our findings point to hydration as a critical and overlooked part of chronic disease prevention. A simple blood test might flag people who could benefit from basic lifestyle adjustments—like drinking more water, which reduces sodium levels,” said the study’s lead author, Prof. Jonathan Rabinowitz, from the Weisfeld School of Social Work at Bar-Ilan University. Rabinowitz collaborated on the research with Dr. Natalia Dmitrieva, from the National Institutes of Health (NIH).

“Hydration is often overlooked in chronic disease prevention,” added Rabinowitz. “This study adds compelling evidence that staying well-hydrated may help reduce the long-term risk of serious conditions like hypertension and heart failure.”

With population aging and chronic disease rates on the rise, these insights may inform future clinical guidelines, preventive screenings, and public health campaigns aimed at encouraging healthy hydration habits.

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