Ageing is inevitable, but how fast it happens can vary widely from person to person. Some people remain healthy and active well into their senior years, while others develop chronic diseases early. The question that has intrigued scientists for years is: what determines the pace of ageing? While genetics play a role, lifestyle factors such as diet, exercise, and hydration also influence the process.
New research suggests that hydration could be a key factor in slowing biological ageing. A recent study found that people with higher serum sodium levels—often a sign of inadequate hydration—age faster, develop chronic diseases earlier, and face a higher risk of premature death. These findings highlight the importance of maintaining proper hydration throughout life, especially in middle age.
Role of Hydration in the Body
Water is essential for every function in the body. It helps regulate temperature, transport nutrients, and flush out waste. Hydration affects organ function, energy levels, and even mental clarity. When the body does not receive enough water, it activates water conservation mechanisms. This process increases sodium concentration in the blood, signaling the body to retain fluids. While this helps in the short term, prolonged dehydration can lead to long-term health issues.
Research has shown that even mild dehydration can impact metabolism, cardiovascular health, and cognitive function. As people age, the ability to regulate hydration decreases. Older adults often feel less thirsty and may not drink enough fluids, increasing the risk of dehydration-related health problems. The recent study provides evidence that hydration levels in middle age can predict long-term health outcomes, making early intervention crucial.
Serum Sodium and Ageing
The study analyzed data from the Atherosclerosis Risk in Communities (ARIC) project, which followed over 15,000 participants aged 45–66 for 25 years. Researchers used serum sodium levels as an indicator of hydration habits. They found that people with sodium levels above 142 mmol/L had a 39% higher chance of developing chronic diseases such as heart failure, stroke, and diabetes. Those with levels above 144 mmol/L faced a 21% increased risk of premature death.
These findings suggest that maintaining hydration could help slow biological ageing. The study also found that individuals with higher sodium levels were more likely to have a biological age exceeding their chronological age. Biological age is calculated using age-related biomarkers and is considered a better predictor of health risks than chronological age alone.
Link Between Hydration and Chronic Diseases
One of the most striking findings of the study was the connection between hydration and chronic diseases. Participants with serum sodium levels in the 138–140 mmol/L range had the lowest risk of developing serious health conditions. Both higher and lower sodium levels were linked to an increased risk. This suggests that hydration balance is essential, as both excessive and insufficient water intake can be harmful.
Heart disease, dementia, chronic lung disease, and stroke were among the conditions most strongly associated with high serum sodium levels. The study indicated that long-term dehydration could contribute to degenerative changes in multiple organ systems, accelerating the onset of these diseases. Given that chronic diseases are a leading cause of disability and healthcare costs, improving hydration could have widespread benefits.
How Hydration Affects Biological Ageing
Ageing is often measured by chronological age, but biological age provides a more accurate picture of overall health. Biological age is determined using biomarkers that reflect the condition of the body's systems. The study found that people with higher sodium levels had a significantly increased biological age compared to their actual age.
This connection suggests that inadequate hydration could contribute to cellular and metabolic stress, accelerating aging at a fundamental level. Previous research in animal models has shown that mild dehydration triggers inflammation, oxidative stress, and DNA damage—all processes linked to ageing. In humans, high sodium levels have been associated with increased vascular stiffness, kidney strain, and metabolic changes, all of which can lead to premature ageing.
Hydration as a Public Health Priority
Despite the known importance of water intake, studies indicate that more than half of adults do not consume enough fluids daily. Hydration is often overlooked in public health discussions, but this study suggests it should be a higher priority. Given the potential link between hydration and ageing, simple changes in daily water intake could have long-term health benefits.
Public health recommendations may need to place greater emphasis on hydration as part of chronic disease prevention. While current guidelines suggest a daily fluid intake based on individual factors, many people fail to meet even the minimum requirements. Raising awareness about hydration’s role in ageing and disease prevention could encourage better habits across all age groups.
Need for Further Research
Although this study provides strong observational evidence, more research is needed to confirm causation. Clinical trials could help determine whether increasing hydration directly slows ageing and reduces disease risk. The field of geroscience, which focuses on slowing biological ageing to improve health, is increasingly interested in hydration’s role.
One challenge in studying hydration is that it varies between individuals. Factors such as climate, physical activity, and diet influence water needs. Future research should aim to develop personalized hydration guidelines based on biological markers. If hydration is proven to slow ageing, it could become one of the simplest and most cost-effective health interventions available.
Practical Steps for Better Hydration
While scientists continue to explore hydration’s impact on ageing, there are practical steps people can take to improve hydration habits. Drinking water consistently throughout the day, rather than relying on thirst alone, can help maintain optimal sodium levels. Foods with high water content, such as fruits and vegetables, also contribute to hydration.
People who frequently experience dry mouth, fatigue, or dark-colored urine may already be mildly dehydrated. Adjusting water intake based on activity levels, weather conditions, and overall health can help maintain balance. Regular medical checkups that include hydration assessments may also help individuals identify potential risks early.
Conclusion
Hydration is often overlooked in discussions about ageing, but this study suggests it plays a vital role in long-term health. Maintaining balanced hydration levels could slow biological ageing, lower the risk of chronic diseases, and extend life expectancy. While more research is needed to confirm the exact mechanisms, drinking enough water is a simple and effective way to support overall well-being.
For now, staying hydrated remains one of the easiest health choices a person can make. Whether through water intake, diet, or awareness of hydration needs, small changes could lead to significant benefits in ageing and longevity.
The study is published in the journal EBioMedicine. It was led by Natalia I. Dmitrieva from National Heart Lung and Blood Institute.
