Adults who aren't sufficiently hydrated may age faster, face a higher risk of chronic diseases and be more likely to die younger than those who stay well-hydrated, according to a new study from the National Institutes of Health. The Health Pioneer shares the details of the study

NIH findings based on data collected over 25 years from more than 11,000 adults in the U.S may provide early clues about increased risks for advanced biological aging and premature death. The participants attended their first medical visits at ages 45 to 66, then returned for follow-ups through at ages 70 to 90.

The researchers looked at levels of sodium in the participants' blood as a proxy for hydration, because higher concentrations are a sign that they most likely weren't consuming enough fluids. The researchers found that the participants with high blood-sodium levels aged faster physiologically than those with lower levels, which was reflected in health markers associated with aging, like high blood pressure, cholesterol and blood sugar.

The study participants all had blood-sodium concentrations considered to be within the normal range: 135 to 146 millimoles per liter. But the findings suggested that people with levels at the higher end of that normal range - above 144 millimoles per liter - were 50% more likely to show signs of physical aging beyond what would be expected for their years compared to people with lower blood-sodium levels. They also had a roughly 20% increased risk of premature death.

Even people with blood-sodium levels above 142 millimoles per liter had elevated risks of developing certain chronic diseases, including heart failure, stroke, chronic lung disease, diabetes and dementia, the study found.

 "Risk to develop these diseases increases as we age and accumulate damages in various tissues in the body," one of the study's authors, Natalia Dmitrieva, a researcher at the NIH's National Heart, Lung, and Blood Institute said.

 Dmitrieva's previous research similarly found that higher blood sodium may be a risk factor for heart failure.

 Just as regular physical activity and proper nutrition are considered part of a healthy lifestyle, she said, "emerging evidence from our and other studies indicate that adding consistent good hydration to these healthy lifestyle choices may slow down the aging process even more."

She noted that most people can safely increase their fluid intake to meet recommended levels, which can be done with water as well as other fluids, like juices, or vegetables and fruits with a high water content. The National Academies of Medicine, for example, suggest that most women consume around 6-9 cups (1.5-2.2 liters) of fluids daily and for men, 8-12 cups (2-3 liters).

Others may need medical guidance due to underlying health conditions. "The goal is to ensure patients are taking in enough fluids, while assessing factors, like medications that may lead to fluid loss" said Manfred Boehm, a study author and director of the Laboratory of Cardiovascular Regenerative Medicine. "Doctors may also need to defer to a patient's current treatment plan, such as limiting fluid intake for heart failure." The authors also cited research that finds about half of people worldwide don't meet recommendations for daily total water intake, which often starts at 6 cups (1.5 liters). 

"On the global level, this can have a big impact," Dmitrieva said. "Decreased body water content is the most common factor that increases serum sodium, which is why the results suggest that staying well hydrated may slow down the aging process and prevent or delay chronic disease."

 But the study authors cautioned that more research is needed to determine whether good hydration can help slow aging, prevent disease or lead to a longer life.