Staying well-hydrated may add years to your life and even keep chronic conditions at bay, according to new research.
By Becky Upham
Looking to make a low-effort, high-payoff change to your everyday health habits? A new study found that people who stay well hydrated appear to be healthier, develop fewer chronic conditions (including stroke, diabetes, and dementia), and live longer compared with people who may not be drinking enough fluids.
The National Institutes of Health (NIH) study was published on January 2, 2022, in the journal eBioMedicine.
“The results suggest that proper hydration may slow down aging and prolong a disease-free life,” said study author Natalia Dmitrieva, PhD, a researcher at the National Heart, Lung, and Blood Institute in Bethesda, Maryland, in a press release.
Staying Hydrated Can Help You Stay Healthy
In the short term, getting enough water can help prevent dehydration, a health issue that can cause your body to overheat, cloud your thinking and mood, and lead to constipation and kidney stones, per the Centers for Disease Control and Prevention (CDC).
According to the agency, staying hydrated in the short term can also help lubricate and cushion joints, protect your spinal cord and other sensitive tissues in your body, and get rid of waste.
Scientists know less about the long-term impact of hydration and dehydration. Existing evidence suggests that less-than-optimal hydration may increase the risk for disease and lead to early death, according to the authors.
In research using mice, lifelong restriction of water intake shortened their life span by six months, which equals about 15 years of human life, according to research published in September 2019 in the journal JCI Insight.
How Do You Measure Biological Age and Hydration?
Given that the U.S. Census Bureau indicates the national median age continues to increase, and with chronic health conditions becoming more widespread, the NIH researchers designed their study to explore whether maintaining an optimal state of hydration might slow the aging process.
Investigators used health data from 11,255 Black and white adults from the Atherosclerosis Risk in Communities study (ARIC), collected over a 30-year period. The first assessment was in 1987 when participants were in their forties or fifties; the average age of participants at the final assessment during the study period was 76 years old.
The authors estimated biological age (how well the body works, versus a person’s chronological age) using biomarkers of different organ systems and processes, including cardiovascular, renal (relating to the kidneys), respiratory, metabolic, immune, and inflammatory measurements.
Rather than try to track the fluid intake of participants, researchers used serum sodium level as an indicator of hydration status. Serum sodium level is a measurement of how much sodium is in your blood: The more hydrated you are, the lower your serum sodium will be. The test is typically performed as part of routine yearly blood work, and the normal range is between 135 to 146 milliequivalents per liter (mEq/L).
Being ‘Optimally Hydrated’ Was Associated With a Lower Risk of Chronic Disease
After adjusting for factors that could influence the findings, including age, race, biological sex, smoking status, and high blood pressure, the NIH scientists found that adults with serum sodium levels at the higher end of the normal range had worse health outcomes than those at the lower end of the range.
Adults with levels above 142 mEq/L were 10 to 15 percent more likely to be biologically older than their chronological age compared with participants in the 137 to 142 mEq/L range.
Those “faster aging” participants with higher levels of serum sodium also had a 64 percent higher risk for developing chronic diseases such as heart failure, stroke, atrial fibrillation, peripheral artery disease, chronic lung disease, diabetes, and dementia.
People with levels above 144 mEq/L had a 50 percent higher risk of being biologically older and a 21 percent higher risk of dying early compared to people with a level between 137 to 142 mEq/L.
The group with the lowest risk of developing chronic disease had a serum sodium levels between 138 to 140 mEq/L.
Drinking Less Water May Be Connected to Obesity
Richard Johnson, MD, a professor of medicine, clinician, and researcher at the University of Colorado in Aurora who was not involved in the NIH study, says that there is a wide variation in how much salt we consume.
According to Dr. Johnson, it has long been understood that people who are obese or predisposed to becoming obese tend to consume more salt and less water, which together raise the blood’s sodium levels.
“Our animal experiments suggest that this process may actually activate processes that can lead to diabetes and obesity. According to this paper, there is proof that this is the situation in people, he says.
According to Johson, the findings of the NIH study indicate that the sodium level in blood can predict the risk for chronic diseases and even aging: The startling discovery is that elevated risk is predicted by sodium levels that are thought to be normal but on the high end. This supports other data that indicate many of us do not hydrate well.
The NIH researchers stressed that although there is an association between the two, there is still no proof that optimal hydration lowers the risk of early death; further research involving randomized, controlled trials is required.
The study does, however, support the notion that people should try to abide by the current guidelines for fluid intake, according to the authors.
Johnson agrees, saying that although a higher serum sodium is associated with higher risk, this study doesn’t prove that the serum level caused that risk. “However, studies in laboratory animals have identified biological mechanisms by which mild dehydration can cause obesity,” he says.
How Much Water Should You Drink Every Day?
How much water is enough? There is no concrete recommendation of how much water everyone should drink, according to the CDC, but research from the U.S. National Academies of Sciences, Engineering, and Medicine determined that an adequate daily intake is 15.5 cups of fluid for men and 11.5 cups for women. That includes all beverages (not just water) and even food — about 20 percent of your fluid intake comes from food.
“I think it is a good idea to drink a glass of water with each meal, and to drink some water throughout the day. Targeting the National Academy of Medicine recommendations is a good idea,” says Johnson. Measuring your serum sodium might be helpful as well, he adds.
Need a little extra help getting enough water? Erin Coates, RD, a health coach at Cleveland Clinic in Ohio, suggests putting five rubber bands around a 16-ounce water bottle every morning. Every time you finish a bottle, take one of the bands off, with the goal of removing all five bands by the time you go to bed.
Note that some people should check in with their doctor before upping their fluid intake. “If you do have serious health issues, like heart failure, or a low serum sodium, I recommend discussing with your doctor before you drink a lot of water. Marathon runners can also hold onto too much water with extensive exercise, and this group should only drink when thirsty,” says Johnson.