Most Israelis were aware enough of last week’s nearly 40 C temperatures and drank a lot of water. Nevertheless, many don’t consume enough liquid on ordinary days – even when it’s cold outside – and as a result could have a higher risk of heart failure and high blood pressure (hypertension).
Water reduces sodium levels. Researchers at Ramat Gan’s Bar-Ilan University, in a landmark study, found that people worldwide with sodium (salt) levels at the higher end of the “normal” range are significantly more likely to develop those two most common age-related chronic diseases. They have just published their findings in the European Journal of Preventive Cardiology under the title “Risk of hypertension and heart failure linked to high-normal serum sodium and toxicity in general healthcare electronic medical records.”
They analyzed electronic health records from between 2003 and 2023 of an impressive 407,000 healthy adults who were members of Leumit Healthcare Services, the smallest of the four public health funds. It was one of the largest and longest-running analysis to date examining the link between hydration status and cardiovascular health.
Sodium levels of 140 to 142 mmol/L (still within normal range) were linked to a 13% higher risk of hypertension and a 20% higher risk of heart failure. Almost 60% of the healthy adult population had sodium levels in ranges associated with these risks. Many Israelis add a lot of salt to their food or regularly eat salty snacks.
Sodium, which is routinely tested in standard blood tests, has long been considered normal within the 135 to 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, smoking, body mass index, blood pressure, and potassium levels. The analysis did not include people with medical conditions that affect water balance, in order to ensure a more accurate reflection of hydration-related risk.
“The aging of the population is driving a global epidemic of age-dependent chronic diseases, including cardiovascular, chronic respiratory, musculoskeletal, neurological, and mental disorders. These disorders in those aged 60 years and older account for about 23% of the total global disease burden, and this proportion is rapidly increasing as life expectancy rises,” said the study’s lead author, Prof. Jonathan Rabinowitz from BIU’s School of Social Work, who collaborated on the research with Dr. Natalia Dmitrieva, from the US National Institutes of Health (NIH).
“Thus, identifying mechanisms and implementing preventive measures to decelerate the aging process have emerged as new challenges for biomedical research and public health.”
“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 – such as drinking more water, which reduces sodium levels,” he continued.
He told The Jerusalem Post that the team had decided to work with Leumit because the health fund is “very cooperative and has the longest computerized medical records among all the health funds. I work with health statistics and have a wellness lab at the university where I look for tweaks that can have a positive impact on people’s health.”
Rabinowitz, who was born in Indiana but made aliyah from Cleveland 35 years ago, said that usually, personal physicians here don’t routinely ask patients how much water they drink, “so I wasn’t surprised by our findings. I suggest that people drink two glasses of water – ordinary tap water is fine – before they have their morning coffee.
“They can drink tea without sugar instead of water if they like, but not so many cups of coffee – and certainly not sugar-sweetened or artificially sweetened drinks like cola. One needn’t buy bottled water, as tap water is fine and ordinary plastic bottles can leak harmful plastic into the water, especially when it’s hot.
“Reusable plastic or metallic water bottles are safe. People think that in the winter, they don’t have to drink much, but they are wrong. They can become dehydrated just from the heating inside the house.”
Rabinowitz added that “One doesn’t have to go for a blood test to see if one is drinking enough water; if your urine is clear or light colored, you’re OK (although a multivitamin may affect the color). If it’s dark yellow, you’re not getting enough.”
Healthcare system focus on illness, not wellness
The healthcare system focuses on illness, not wellness. “There are smartphone apps that remind you to drink water, they are very useful – like the apps that check how much you have walked. There are even smart water bottles that measure how much you have drunk and give you an automatic reminder if you haven’t gotten enough. It would be great if a smart watch could know from your skin if you’ve had enough water and send you a reminder.”
The NIH is even studying a connection between lack of hydration and dementia.
Rabinowitz and his team are now doing a national study on walking. “Twenty minutes a day is excellent. Walking with your dog daily, rain or shine, is very beneficial; bring water for yourself and for your pet. It has also been found that people who walked got to work in the same time it took to get there by bus or other public transport.”
"Hydration is often overlooked in chronic disease prevention,” Rabinowitz concluded. “This study adds compelling evidence that staying well-hydrated may help reduce the long-term risk of serious conditions, such as 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, he said.