A 25-year study led by Dmitrieva reveals that optimal hydration can significantly slow aging and reduce chronic disease risk. This research highlights the importance of hydration in maintaining health, suggesting that simple habits like staying well-hydrated and reducing salt and sugar intake can help slow aging and prevent chronic health issues.
Hydration and Aging: Maintaining Optimal Hydration to Delay Aging and Chronic Diseases
In our lives, there are always individuals who appear younger than their actual age or age more slowly than their peers. Some even reach old age without developing age-related chronic diseases. What "skills" do these enviable people possess?
A study by Dmitrieva et al. from the U.S. National Heart, Lung, and Blood Institute, based on a 25-year large-scale observational study, found that when middle-aged individuals have a serum sodium level above 142 mmol/l, the risk of chronic diseases increases by 39%, and the likelihood of appearing biologically older than their actual age rises by 50%. Additionally, when serum sodium levels exceed 144 mmol/l, the risk of premature death increases by 21%. The results suggest that maintaining optimal hydration may help slow down the aging process.
DOI: 10.1016/j.ebiom.2022.104404
Increasing research shows that slowing down the aging process can not only extend health span and improve quality of life but also reduce healthcare costs, with benefits far outweighing the treatment of any single disease. Currently, differences in biological aging speeds can already be detected in middle age, indicating that if effective preventive measures are taken earlier in life, it is possible to delay aging and reduce the burden of chronic diseases.
In recent years, several epidemiological studies have shown correlations between hydration markers and the occurrence and development of heart failure, metabolic diseases, and mortality rates. Follow-up surveys lasting 3 to 6 years revealed that when serum sodium levels are at the upper limit of the normal range (primarily influenced by diet and drinking habits), the risk of death significantly increases. Based on these findings, scientists hypothesize that optimal hydration may delay the aging process. This hypothesis was confirmed by analyzing the ARIC (Atherosclerosis Risk in Communities) study data, a large-scale, ongoing, 25-year cohort study that provides clinical thresholds for serum sodium levels in middle-aged individuals to identify high-risk groups. The research findings were published in eBioMedicine.
The study included 11,255 participants, with an average age of 57. As the body’s hydration and serum sodium levels remain relatively stable, the researchers assumed that the average serum sodium between the first and second measurements could reflect participants' long-term hydration habits. The results showed that the mortality rate was lowest in individuals with serum sodium levels between 137-142 mmol/l (26.2%, n = 8604), while those with levels of 135-136.5 mmol/l (39.3%, n = 122) and 144.5-146 mmol/l (34.5%, n = 397) had significantly higher mortality rates. Kaplan-Meier survival analysis confirmed that mortality rates increased in groups with serum sodium lower than 137 mmol/l or higher than 142 mmol/l.
Figure 1. Association between serum sodium and all-cause mortality risk in the middle-aged cohort in the Atherosclerosis Risk in Communities (ARIC) study
As age increases, the incidence of chronic diseases also rises (Figure 2a). The study assessed 5,168 participants aged 70-90 years, who participated in five follow-up evaluations. The study focused on four degenerative diseases: heart failure, dementia, chronic lung disease, and stroke. The analysis revealed that individuals with serum sodium levels between 138-140 mmol/l had the lowest risk of chronic diseases, while higher serum sodium levels were associated with an increased risk. Time-event analysis showed that individuals with serum sodium levels above 140 mmol/l had a 63% higher chance of developing chronic diseases compared to those with levels between 138-140 mmol/l.
Figure 2. Association between serum sodium in middle age and risk of chronic diseases in old age
Biological Age: The Relationship Between Serum Sodium and Aging Speed
Biological age (BA) better reflects the individual’s aging speed compared to actual age. In this study, participants were grouped based on their actual age, biological age (BA), and the difference between BA and actual age (BA-Age). The results showed that groups with a BA older than their actual age by more than 7 years had a 50% higher risk of premature death and a 44% higher risk of chronic disease compared to other groups. Furthermore, a 3D mesh plot visualizing the relationship between serum sodium and age showed that participants with higher serum sodium levels in the upper normal range typically had a biological age higher than their actual age.
Figure 3. Higher biological age is associated with an increased risk of premature death and/or age-related chronic diseases
After adjusting for age, gender, race, and smoking status, logistic regression analysis further confirmed that participants with serum sodium levels above 142 mmol/l had a 10-15% higher chance of having a biological age greater than their actual age. When serum sodium exceeded 144 mmol/l, this probability increased to about 50%.
Figure 4. ARIC study participants with serum sodium levels above the normal range had an increased chance of being biologically older than their actual age
Conclusion and Recommendations
In summary, this study points out that middle-aged individuals with serum sodium levels above the normal range not only age more rapidly but also have a higher burden of chronic diseases in later life. The incidence of diseases such as heart failure, dementia, chronic lung disease, stroke, diabetes, peripheral vascular disease, and atrial fibrillation is higher in these individuals. The study clearly indicates that the serum sodium threshold for middle-aged individuals is 142 mmol/l. Therefore, maintaining appropriate hydration is crucial. Since dehydration is the primary cause of increased serum sodium levels, ensuring sufficient water intake and reducing high-salt and high-sugar diets are practical anti-aging strategies that everyone can implement.