Could hydration hold the key to longevity?
Maybe, suggests new research that discovered older adults who are properly hydrated may be healthier and live longer than those who aren't, having less incidence of conditions like heart and lung disease.
"Staying well-hydrated may slow down aging, prevent or delay development of chronic diseases, and therefore prolong disease-free life," said lead investigator Natalia Dmitrieva, a researcher from the Laboratory of Cardiovascular Regenerative Medicine at the U.S. National Heart, Lung and Blood Institute.
"The best way for people to keep well-hydrated is to be aware of the amount of fluids they drink without engaging in intensive sports activities or [spending] a long time in a hot environment," Dmitrieva said.
The current recommendations vary from 2 to 3 liters of fluid daily -- for women, that's 6 to 9 cups of fluids like water each day, while men need around 8 to 12 cups, she said.
"Worldwide population surveys estimate that more than 50% of people drink less fluid than recommended and therefore have an opportunity to decrease their risk of developing chronic diseases by increasing water intake to the recommended levels," Dmitrieva said.
Samantha Heller, a senior clinical nutritionist at NYU Langone Health in New York City, agreed that being well-hydrated is essential for healthy living.
"Our bodies work hard to maintain a healthy fluid balance, which includes keeping serum sodium levels [blood salt levels]) tightly regulated. Triggering thirst is one way the body signals us that we need to consume more water. Drinking too much or too little water can result in serious physiological disturbances in the body's fluid balance," she said.
But drinking water isn't the only way to maintain good hydration, Heller said.
"Hydration requirements can be met through the consumption of certain foods, such as fruits and vegetables, as well as beverages. It's best to avoid drinking sugar-sweetened beverages and diet drinks," she said. Opt for water, seltzer, tea and herbal teas like peppermint, chamomile and ginger.
Drink up, yes, but don't overdo it. Drinking too much water also has a downside, Dmitrieva said.
"Drinking too much water can be dangerous. If the kidney cannot excrete excess water, the sodium content in the blood becomes diluted. This is called hyponatremia and it can be life-threatening," she said.
There is no need to drink more than 3 liters per day if there is no excessive water loss due to exercise or prolonged heat exposure, Dmitrieva said. "If you drink more than 3 liters per day and still feel thirsty, it could be an indication of a disease condition that results in pathologically increased water losses and requires clinical evaluation."
For the study, Dmitrieva and her colleagues tracked data over three decades on more than 11,200 adults who took part in the Atherosclerosis Risk in Communities study. Participants were seen over five visits -- two in their 50s, and the last between the ages of 70 and 90.
To judge how well-hydrated they were, the researchers looked at levels of salt in the blood, gleaning information on systolic blood pressure, cholesterol and blood sugar. Those markers, in turn, indicated how well the cardiovascular, respiratory, metabolic, renal and immune systems were functioning.
Adults whose salt level was higher than normal were more likely to suffer from chronic conditions and have signs of advanced biological aging, compared with those whose salt levels were in the medium range. Those with high levels of salt were also more likely to die younger.
Specifically, people with high salt levels had 50% higher odds of being biologically older than their chronological age and 21% higher odds of dying early, compared with those whose salt levels were low. High levels of salt were also linked to a 64% increased risk of developing heart failure, stroke, atrial fibrillation and artery disease, as well as lung disease, diabetes and dementia, the researchers found.
This study, however, can't prove that staying hydrated has all these benefits, only that they seem to be linked, the researchers noted.
"Proper hydration supports the body's many functions, and over time, taking in enough fluids may slow down aging and support a long, healthy life," Dmitrieva said.
Heller said it's important to listen to one's body and drink when thirsty. "Aging is a natural process," she added, "but we can slow certain effects of aging by living a healthy lifestyle that includes a balanced, more plant-forward diet, regular exercise, adequate sleep and maintaining appropriate hydration."
The report was published online Jan. 2 in the journal eBioMedicine.
For more on good hydration, visit Nutrition.Gov.
SOURCES: Natalia Dmitrieva, PhD, researcher, Laboratory of Cardiovascular Regenerative Medicine, U.S. National Heart, Lung, and Blood Institute; Samantha Heller, MS, RD, CDN, senior clinical nutritionist, NYU Langone Health, New York City; eBioMedicine, online, Jan. 2, 2023