Dehydration is a significant risk factor for heart failure, concludes a study published in the European Heart Journal by researchers at the National Institutes of Health (NIH).
 
Heart failure, a condition in which the heart pumps an insufficient amount of blood, affects 6.2 million Americans, roughly 2% of the population, and is more common among seniors.
 
“Similar to reducing salt intake, drinking enough water and staying hydrated are ways to support our hearts and may help reduce long-term risks for heart disease,” Natalia Dmitrieva, PhD, lead study author and researcher in the Laboratory of Cardiovascular Regenerative Medicine at the National Heart, Lung, and Blood Institute (NHLBI), of NIH.
 
The team of researchers built a large-scale population study based off of preclinical research which suggested connections between dehydration and cardiac fibrosis, a hardening of the heart muscles. They analyzed data from 15,000 adults between the ages of 45 and 66 who enrolled in the Atherosclerosis Risk in Communities study which had 25-year follow up data from medical visits.
 
Data from approximately 11,814 adults were included in the final analysis, and of those adults, 1,366 later developed heart failure. To assess potential links with hydration, the researchers assessed the hydration of the participants at medical visits using serum sodium, which increases as the body’s fluid levels decrease.
 
The normal range of serum sodium levels is 135-146 mEq/L. For serum sodium levels beginning at 143 mEq/L (milliequivalents per liter) in midlife, there was a 39% increased risk of heart failure compared to adults with lower levels. For every one mEq/L increase in serum sodium within the normal range, the likelihood of a participant developing heart failure increased by 5%.
 
In the cohort of older adults between the ages of 70 and 90, those with serum sodium levels between 142.5 and 143 mEq/L correlated with a 102% increased risk for left ventricular hypertrophy, an enlargement and thickening of the heart, and a 54% increased risk for heart failure.
 
The authors concluded based on the observational data that serum sodium levels above 142 mEq/L in middle age are associated with increased risks for both left ventricular hypertrophy and heart failure later in life. They noted that a randomized, controlled trial will be necessary to confirm these findings.
 
“Serum sodium and fluid intake can easily be assessed in clinical exams and help doctors identify patients who may benefit from learning about ways to stay hydrated,” said Manfred Boehm, MD, who leads the Laboratory of Cardiovascular Regenerative Medicine.
 
Based on the amount necessary to achieve beneficial hydration levels within the study, the authors recommended that women have between six and eight cups of fluid per day, and between eight and 12 cups of fluid per day for men.