Most of us think of dehydration as something temporary: feeling thirsty after exercise, spending a hot day outside or simply forgetting to drink enough.
But researchers are also interested in a different question: could consistently low hydration over many years be related to how our bodies age?
Long-term population research suggests there may be a connection.
Hydration Is Important Throughout the Body
Water is involved in almost every major physiological process.
It helps maintain blood volume and circulation, regulates body temperature, transports nutrients and supports normal kidney function. It also allows the kidneys to remove many metabolic waste products from the blood and excrete them in urine.
When water availability falls, the body activates powerful mechanisms to conserve water and maintain the concentration of sodium and other substances in the blood within a narrow range.
This means that hydration is not simply about how much water you drink on a particular day. It is part of a tightly regulated physiological balance.
What Does Biological Age Tell Us?
In a large US study, researchers followed adults for approximately 25 years and examined whether hydration-related measures in middle age were connected with later health.
They used serum sodium as an indirect indicator of habitual hydration. Within the normal range, higher sodium can sometimes reflect lower water availability.
Participants with serum sodium above 142 mmol/L were more likely to have an estimated biological age greater than their chronological age.
Biological age in this study was calculated from several clinical measures reflecting how different systems of the body were functioning.
The same higher sodium levels were also associated with a greater risk of developing chronic diseases later in life.
Does This Mean Dehydration Accelerates Aging?
Not yet.
The study identified an association. It did not demonstrate that inadequate hydration directly caused faster biological aging.
Serum sodium is also not a direct measurement of how much water someone drinks. Kidney function, hormones, medications and medical conditions can all influence it.
Most importantly, the study did not test whether increasing water intake could make biological age younger.
What it does show is that long-term water balance may be another factor worth considering in healthy aging.
Maintaining adequate hydration is already important for normal physiology. Whether consistently good hydration can also help slow biological aging is now an important question for future research.
Based on Research
Dmitrieva NI, Gagarin A, Liu D, Wu CO, Boehm M. Middle-age high normal serum sodium as a risk factor for accelerated biological aging, chronic diseases, and premature mortality. eBioMedicine. January 2023.
