Hydration linked to lower risk of heart disease

Israeli researchers have found that people with higher blood sodium levels — even within the normal range — face greater risks of developing high blood pressure and heart failure, but staying well-hydrated may help lower those risks.

The study, conducted by Bar-Ilan University and published in the European Journal of Preventive Cardiology, analyzed 20 years of health records from over 407,000 healthy adults. It revealed that individuals with sodium levels between 140–146 mmol/L had significantly higher chances of developing cardiovascular problems, with those above 143 mmol/L facing a 29% increased risk for hypertension and 20% for heart failure.

“Sodium concentration in the blood reflects hydration,” said lead researcher Prof. Jonathan Rabinowitz. “A simple blood test might flag people who could benefit from basic lifestyle adjustments—like drinking more water, which reduces sodium levels.”

The findings suggest hydration is a key, often overlooked factor in chronic disease prevention. Blood sodium rises when hydration levels drop, signaling that even healthy people may be at risk if underhydrated. Nearly 60% of study participants had sodium levels in the risk range.

The associations held true even after controlling for age, sex, BMI, smoking, potassium, and blood pressure. Those with medical conditions affecting fluid balance were excluded.

The U.S. National Academies recommend daily fluid intakes of about 3.7 liters for men and 2.7 liters for women, though individual needs may vary.