The Surprising Link Between Hydration and the Aging Process

A new study by the National Institutes of Health (NIH) published by eBioMedicine identifies the key role hydration is thought to play in the aging process. This new research serves as great proof of the importance of drinking enough water to stay properly hydrated.

The study determined that middle-aged persons with higher sodium-to-water levels in their blood biologically age faster. They are also more likely to develop chronic diseases – such as diabetes, heart failure, and dementia – and to die prematurely.

Decreased hydration levels were actually shown to accelerate the process of biological aging despite chronological age, our age measured in years from our birth.

According to an NIH press release, “The results suggest that proper hydration may slow down aging and prolong a disease-free life,” said Natalia Dmitrieva, Ph.D., a study author and researcher in the Laboratory of Cardiovascular Regenerative Medicine at the National Heart, Lung, and Blood Institute (NHLBI), part of NIH.

A mouse study inspired the new research

The study was inspired by an earlier study on mice which suggested that restricting water shortened their lives by as much as 6 months, equivalent to about 15 years of life for humans.

Researchers said in the new observational study that their initial goal was to test “the hypothesis that optimal hydration may slow down the aging process in humans.” The study used a large dataset from the federally funded Atherosclerosis Risk in Communities (ARIC) study which included men and women between the ages of 45 and 66 years who were followed over a long period of time.

Researchers in the new study assessed information from ARIC study participants that had been shared during five medical visits – the first two when participants were in their 50s and then the last when they were ages 70 to 90. To allow for a fair comparison, researchers excluded data from adults who already had high levels of serum sodium or underlying conditions like obesity that might affect serum sodium levels.

“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,” said Dmitrieva.

What is serum sodium and why is it important?

Serum sodium was used to gauge hydration habits in the new study. Serum sodium is the amount of sodium relative to the volume of water in the blood, and it goes up as hydration is reduced. Serum sodium can be detected by a simple blood test, and according to the Mayo Clinic, a normal blood sodium level is between 135 and 145 millimoles (mmol) per liter.

Researchers in the recent study used 15 age-dependent biomarkers to calculate the biological age of cohorts from the ARIC study. They found that people with higher serum sodium were biologically older than their cohorts of the same chronological age and also more prone to chronic, debilitating diseases that can reduce quality of life.

More specifically, the study results showed that odds to biologically age beyond one’s chronological age went up by an estimated 10-15 percent for serum sodium exceeding 144 mmol/l and by approximately 50 percent for serum sodium levels above 144 mmol/l, when compared to participants with serum sodium levels between 137-142 mmol/l. Note that these higher serum sodium levels thought to increase biological aging are still within the normal range, even though they’re at the high end of the spectrum.

People in the original blue zones drink lots of water

People in the original blue zones, home to the longest-living populations, make drinking water a part of their daily routines. The Seventh Day Adventists, for instance, drink 7 glasses of water a day.

When asked what the longest-lived people in the world drink, Blue Zones founder Dan Buettner said, “Easy: Clean water is the best longevity beverage on earth.”

Hydrating primarily with water is just one of the recommendations in our Blue Zones Food Guidelines, which were designed so that you can eat – and drink – just like the longest-lived people in the world for the same longevity benefits. The guidelines advise drinking at least 7 glasses of water daily.

Tips that make it easy to get enough water

Here are some tips from the Blue Zones Meal Planner to help you get your daily recommended amount of water.

1. Infuse water with fruits or herbs to add flavor and texture
2. Brew and drink decaffeinated, herbal teas
3. Drink water when you first wake up
4. Eat more hydrating foods like celery, cucumber, apples, and melons
5. Track your daily water intake using a free smartphone app
6. Read our Rethink Your Drink article for ideas on hydrating without added sugars