By Li Cohen
/ CBS News
A new study from Harvard finds more than half of U.S. children and teens aren't drinking enough water to stay properly hydrated
The secret to living a longer and healthier life? At least part of the answer could actually be pretty simple: water.
A new peer-reviewed study published Monday in the journal eBioMedicine, which is part of The Lancet, suggests that people who get proper hydration may be less likely to show signs of aging and chronic illnesses. Researchers analyzed health data from more than 15,700 adults between the ages of 45 and 66 for more than 25 years, specifically looking at their serum sodium levels, or the amount of sodium in their blood. Those levels, researchers said, are a proxy for their hydration habits.
What they found is that people who had more than 142 millimoles of serum sodium — the higher end of a normal range — had a 39% higher risk of developing chronic diseases and up to 50% higher chance of having biological markers of age "older than their chronological age." Those with more than 144 millimoles of serum sodium also had a 21% increased risk of premature mortality.
"The results suggest that proper hydration may slow down aging and prolong a disease-free life," study author Natalia Dmitrieva, a researcher at the National Heart, Lung, and Blood Institute, saidin a news release. "...On the global level, this can have a big impact. 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."
The research does not prove that drinking more water will reduce aging — such a determination would require additional interventional studies — but it does suggest that people with higher levels of sodium in their blood are more likely "to be biologically older, develop chronic disease and die at a younger age," the study says, adding that dehydration is one of the biggest factors that increases those levels.
The optimal serum sodium range for the lowest risk of chronic disease and/or premature mortality, researchers said, is between 138 and 142 millimoles. Those with a level of 142 or higher "would benefit from evaluation of their fluid intake," Dmitrieva said.
Taking a look at your hydration may have other benefits. Proper hydration is essential in helping your body regulate temperature, improving athletic performance, and maintaining proper organ function.
So how much water is enough?
According to the Institute of Medicine of the National Academies, adult women should have an average of 2.7 liters (91 ounces) of water every day while adult men should have about 3.7 liters (125 ounces). But that doesn't all have to be from glasses of water; it also includes water intake from other beverages and food.
Those numbers are based on the expected needs of people who are healthy and relatively inactive in temperate climates, so the true amount of hydration needed for an individual could differ based on physical activity, heat exposure, the amount of food one eats and other variables.
There are also several ways to gauge whether you might not be getting enough water. According to Kaiser Permanente, urine that is a darker color or has noticeably decreased in frequency could be an indicator, as well as bad breath, dry mouth, fatigue and sugar cravings. More significant issues, such as confusion, dizziness, fainting or heart palpitations could also be a sign of dehydration.
Li Cohen is a social media producer and trending content writer for CBS News.
