Staying hydrated may protect your heart, major Bar-Ilan University study finds

A landmark Bar-Ilan University study has found that individuals with sodium levels at the higher end of the "normal" range are significantly more likely to develop hypertension and heart failure, two of the most common age-related chronic diseases worldwide.

The study analyzed electronic health records from 2003-2023 of more than 407,000 healthy adults enrolled in Leumit Healthcare Services, one of Israel’s leading health providers. It is one of the largest and longest-running analyses to date examining the link between hydration status and cardiovascular health. The results were recently published in the European Journal of Preventive Cardiology.

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 populationhad 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.

This research was funded in part by the Elie Wiesel Chair that Rabinowitz holds at Bar-Ilan University and by the Intramural Research Program of the National Heart, Lung, and Blood Institute at the NIH.