Every cell in our body needs water to function correctly. Water makes up 50-70% of our weight, and we have to replace the 2-3 quarts we lose each day.1,2 That replacement comes in the form of liquids and foods we drink and eat. According to The National Council on Aging, we should drink “about one-third” our body weight (pounds) in “that number of ounces in fluids.”3
Natalia Dmitrieva and colleagues recently reported in eBioMedicine that people with high normal sodium, i.e., serum sodium above 142 mmol/l, have worse health and do not live as long as those with serum sodium levels in the rest of the normal range. Although they did not quantify study subjects’ liquid intake, they inferred that higher serum sodiums reflect a lower hydration status.4 Dmitrieva reported on data from 11,255 of the 15,000+ participants in the Atherosclerosis Risk in Communities (ARIC) study. In this subset, they followed serum sodium levels for over 25 years—from middle age to 70-90 years old—analyzing data collected over 5 visits. Dmitrieva reported the average participant age was 57 years at visit 2, with 53% women, 47% men, 80% white, and 20% Black. By visit 5, participants averaged 76 years old, with 56% women, 44% men, 82% white, and 18% Black. This study also used 15 biomarkers including systolic blood pressure, creatinine, uric acid, glucose, cholesterol, and albumin, and adjusted for factors such as age, race, biological gender, hypertension, and smoking status that can affect sodium.
In their research, those adults with serum sodium levels greater than 142 mmol/l ‘’had a 39% increased risk to develop chronic diseases” and had signs that suggested faster biological aging—“up to 50% higher odds to be older than their chronological age.” Participants with serum sodium levels in a range of 144.5-146 mmol/l had a 21% greater risk of “premature mortality” than those within a lower range of 137-142 mmol/l.
The researchers conclude that those with higher sodium, which they attributed to lower hydration as a primary contributing factor, have an increased risk for developing chronic diseases and dying at a younger age; they considered the threshold of 142 mmol/l a clinical threshold to identify those at higher risk. A key limitation of the study arises from its observational nature–because they do not measure water intake, one cannot know whether the problem was due to hydration alone or at all. Other factors such as dietary sodium intake or sodium depleting medications, such as diuretics provide alternate mechanisms that could elevate sodium. We also do not know if additional hydration could have reversed the sodium deficit or changed the observed outcomes.
This study postulates that individuals who maintain good hydration levels develop fewer chronic health conditions. Water performs many important functions within our bodies. Hydration helps with digestion, waste removal, joint lubrication, brain and bone cushioning, oxygen transport throughout the body, temperature regulation, and more.5
However, it is indisputable that dehydration–not hydrating enough to support one’s body functions—can quickly harm the body. Dehydration can result in dizziness, muscle cramps, constipation, how hard the heart has to work to pump blood, confusion, headaches, delirium, and death.
Older adults are especially susceptible to becoming dehydrated compared with younger people. Because as we age thirst sensation decreases, older adults may not notice when their body requires fluids. Some people lose kidney function as they age or develop problems causing incontinence, so they drink less to limit restroom trips. Such instances can cause an imbalance in body fluids, and even lead to dehydration. What this all boils down to is everyone should heed their body’s cravings for fluids. And, if we are older, perhaps we need a little more diligence to keep appropriately hydrated. Hydration, the study suggests, can promote a possibly healthier and longer life. Perhaps, better hydration may even bring us one step closer to a “fountain of youth.”