This article is part of our series about hydration.

How much water do we really need? How does hydration actually work? And what are the specific health benefits associated with maintaining proper hydration? As we embrace the summer season and brace ourselves for the soaring temperatures, it’s crucial to prioritize our well-being by taking necessary precautions.

Stay tuned to discover the correlation between hydration, heart failure and longevity.

 

Heart failure (HF) is a significant concern for public health, particularly in developed countries with increasing numbers of elderly individuals. In the United States, approximately 6 million adults are living with HF, according to the 2021 American Heart Association statistical update, which is more than 2 % of the US population (1). There are an estimated 64.3 million individuals worldwide with heart failure (1). The condition is more common among individuals ages 65 and older.

 

How is heart failure related to hydration?

When a person becomes dehydrated, their blood becomes more concentrated due to increased sodium levels. The body has mechanisms to maintain a balance of sodium levels in healthy individuals, such as thirst and antidiuretic hormone release. These mechanisms are activated when there is a decrease in water intake, and they work to keep sodium levels within a normal range. The concentration of sodium in the blood is the main factor that affects its balance, and this is regulated by the release of antidiuretic hormone, which acts on the kidneys to excrete less urine. When the body becomes dehydrated, the blood’s volume decreases, and this can lead to hypertension and heart failure.

 

Staying hydrated may help reduce the long-term risk for heart failure

The findings of a recent study provide evidence that having slightly higher levels of serum sodium within the normal range due to chronic lifelong subclinical hypohydration (mild dehydration over a long period of time) may lead to an increased risk of developing heart failure (1).

The study explored the relationship of serum sodium levels at middle age and the risk of heart failure. The researchers first looked at preclinical studies to form their hypothesis. The idea behind this hypothesis came from studies that used a mouse model of mild water restriction (2)- (3). These studies found that when the mice were given less water over several weeks or their whole lifetime, their serum sodium levels increased. This change in water intake was linked to various changes in the body that are associated with cardiovascular risks, such as increased inflammation, blood clotting, and damage to the arteries. As a result, the lifespan of the mice was shortened by 6 months (20%) and their hearts showed signs of fibrosis.

To investigate the proposed link between long-term hypohydration and heart failure, the researchers examined information from the Atherosclerosis Risk in Communities (ARIC) study. The ARIC study is a continuing research project that follows a group of more than 15 000 adults aged 45 to 66 years from four different US communities. This population-based study began in 1987-89 and has been tracking participants for over 25 years. Both black (African American) and caucasian men and women are included in the study.  The researchers chose to look at individuals who had normal hydration levels, without diabetes, obesity, or heart failure at the beginning of the study when conducting their retrospective analysis.

The results of the study showed that higher serum sodium levels in middle age were associated with an increased risk of heart failure later in life. Specifically, the risk of heart failure was highest among individuals whose serum sodium levels were in the upper part of the normal range (between 142-143 mmol/L).  The normal range of serum sodium is 135–146 mmol/l.

The study also found that the association between serum sodium levels and heart failure risk was independent of other cardiovascular risk factors such as age, sex, blood pressure, and smoking status, and salt intake. Overall, the study suggests that serum sodium levels in the upper part of the normal range may be a risk factor for heart failure in middle-aged individuals. The findings may help inform strategies for preventing heart failure in this population (3).

 

Is hydration linked to longevity?

The same research group conducted an additional study published just few months ago, building upon their hypothesis that optimal hydration could potentially slow down the aging process in humans (4). Using data from the Atherosclerosis Risk in Communities study (the same data mentioned earlier), the scientists performed a cohort analysis and used serum sodium levels as a proxy for assessing hydration habits. Their focus remained on individuals who exhibited normal hydration levels and were free from diabetes, obesity, and heart failure at the study’s outset.

With a cohort of over 11,000 participants, the researchers found that participants with serum sodium levels surpassing 142 mmol/l faced an increased risk of developing chronic diseases and dying at a younger age (4). The study investigated chronic diseases including heart failure, dementia, chronic lung disease, stroke, diabetes, peripheral vascular disease and claudication, atrial fibrillation, and hypertension. Furthermore, higher biological age was associated with a greater risk of chronic diseases and premature mortality.

These findings suggest the necessity for intervention studies to further validate the link between hydration and the aging process. By highlighting the potential repercussions of high normal serum sodium levels in middle-aged individuals, the study underscores the heightened risk of accelerated biological aging, chronic diseases, and premature mortality. Like any observational study, it is important to recognize that factors other than hydration could potentially impact the association between serum sodium levels and longevity. Therefore, additional research is needed to establish a definitive connection between these variables.

 

Interested to learn more about hydration? Explore our articles:

Introduction to hydration article

The benefits of hydration

Hydration and mental health

 

Silviya Demerzhan, Ph.D.

Chief Scientific Officer, Nordic Executive Medicine
Medical review by: Dr. Mahir Vazda MD

References:

  1. Dmitrieva NI, Liu D, Wu CO, Boehm M. Middle age serum sodium levels in the upper part of normal range and risk of heart failure. Eur Heart J. 2022 Sep 14;43(35):3335–48.
  2. Allen MD, Springer DA, Burg MB, Boehm M, Dmitrieva NI. Suboptimal hydration remodels metabolism, promotes degenerative diseases, and shortens life. JCI Insight [Internet]. 2019 Sep 5 [cited 2023 May 7];4(17). Available from: https://insight.jci.org/articles/view/130949
  3. Dmitrieva NI, Burg MB. Elevated Sodium and Dehydration Stimulate Inflammatory Signaling in Endothelial Cells and Promote Atherosclerosis. PLOS ONE. 2015 Jun 4;10(6):e0128870.
  4. 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 [Internet]. 2023 Jan 1 [cited 2023 May 7];87. Available from: https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(22)00586-2/fulltext