A groundbreaking study from Bar-Ilan University has found that even sodium levels on the higher end of the so-called “normal” range are linked to a significantly increased risk of hypertension and heart failure—two of the most widespread chronic diseases associated with aging.
The research, recently published in the *European Journal of Preventive Cardiology*, examined data from over 407,000 healthy Israeli adults treated by Leumit Healthcare Services between 2003 and 2023. The study is among the largest and most comprehensive ever conducted on the connection between hydration and heart health.
Key findings include:
- Adults with sodium levels between 140–142 mmol/L (millimoles per litre – A mole is an amount of a substance that contains a large number––6 followed by 23 zeros––of molecules or atoms. A millimole is one-thousandth of a mole.) had a 13% greater risk of developing high blood pressure.
- Those with sodium levels above 143 mmol/L faced a 29% higher risk of hypertension and a 20% greater risk of heart failure.
- Nearly 60% of the study population fell into these elevated-risk sodium ranges, despite being within the standard “normal” range of 135–146 mmol/L.
These findings challenge long-standing assumptions about what constitutes a “normal” sodium level. According to the researchers, even levels previously considered unremarkable may be signaling insufficient hydration and a higher likelihood of future cardiovascular issues.
Importantly, the study accounted for other risk factors—including age, sex, body mass index, smoking status, and blood pressure—and excluded anyone with medical conditions that affect water balance, ensuring that hydration itself could be reliably assessed as a contributing factor.
“Our results suggest that hydration is a powerful yet often ignored element in preventing chronic disease,” said Prof. Jonathan Rabinowitz, lead author and faculty member at Bar-Ilan’s Weisfeld School of Social Work. “A standard blood test could help identify people who might benefit from something as simple as drinking more water.”
Rabinowitz collaborated with Dr. Natalia Dmitrieva of the U.S. National Institutes of Health (NIH), whose prior work also pointed to dehydration as a potential long-term health risk.
“With the global population aging and chronic disease rates climbing, strategies as basic as promoting better hydration could make a meaningful difference,” added Rabinowitz.
The study was supported by the Elie Wiesel Chair at Bar-Ilan University and the Intramural Research Program of the National Heart, Lung, and Blood Institute at the NIH. Researchers hope the findings will shape future clinical guidelines, screening protocols, and public health efforts focused on cardiovascular disease prevention through better hydration.
