Heart Health: The Link Between Heart Health and Hydration
There are many reasons why staying hydrated is important for good health. It helps regulate body temperature, aids with digestion, and even influences energy levels, among many other positive benefits. Now, research also links good hydration with a reduced risk for heart failure. Researchers from the National Institutes of Health found that consuming sufficient amounts of fluids throughout life not only supports essential body functioning but also may reduce the risk of severe heart problems in the future.
The research, published in the European Heart Journal, suggests that good hydration can prevent or slow changes in the heart that can eventually lead to heart failure, explains study author Natalia Dmitrieva, PhD, of the National Heart, Lung, and Blood Institute, part of the National Institutes of Health in Bethesda, Maryland. The research looked at 15,792 adults in the Atherosclerosis Risk in Communities study. Participants were 44 to 66 years old at recruitment and were evaluated over five visits until age 70 to 90.
Study participants were put into four different groups based on their average serum sodium concentrations at study visits one and two (conducted in the first three years): 135–139.5, 140–141.5, 142–143.5, and 144–146 mmol/l. Serum sodium levels are significant because they increase when fluid levels decline. Researchers then analyzed the proportion of people who developed heart failure and left ventricular hypertrophy at visit five (25 years later) in each group.
According to Dmitrieva, for every 1 mEq/L increase in serum sodium within the normal range of 135–146 mEq/L, the likelihood of the participant developing heart failure increased by 5%.
In a cohort of about 5,000 adults aged 70 to 90, those with serum sodium levels of 142.5–143 mEq/L at middle age were 62% more likely to develop left ventricular hypertrophy. In addition, serum sodium levels starting at 143 mEq/L correlated with a 102% increased risk of left ventricular hypertrophy and a 54% increased risk for heart failure.
Encouraging Better Hydration
“Adverse effects of low hydration on the heart are related to the way our body tries to conserve water when we do not drink enough,” she says. “Low water intake stimulates the secretion of hormones that act on the kidneys, leading to the excretion of lower volumes of more concentrated urine. And these same hormones, if they are constantly present over a long time, also affect the heart, undermining its proper function. These hormones also constrict blood vessels and contribute to the development of hypertension, which is a major risk factor for the development of heart disease because the heart has to work harder to pump blood.”
She adds that drinking the recommended amount of liquid every day is a relatively simple thing that people can do as it doesn’t interfere much with their typical lifestyles.
“The potential benefits are huge,” she continues. “These include decreased risk of future heart disease and a potentially longer disease-free life. People can spend a couple of days estimating how many fluids they habitually drink and then modify their habits to achieve recommended levels.”
According to Dmitrieva, any healthy fluid will work well for hydration. It does not have to be plain water. This is good news for those patients who say that the taste (or lack of it) of water is their main reason for not drinking enough. Of course, sugary beverages are not the best way to hydrate as they have been linked to type 2 diabetes and obesity.
Dmitrieva adds that the CDC has a good website that offers tips on how to stay hydrated and choose healthful drinks. Physicians can recommend that their patients review some of the points covered on www.cdc.gov/healthyweight/healthy_eating/water-and-healthier-drinks.html.
Some of the CDC’s tips to encourage more water throughout the day include carrying a bottle, adding a wedge of lime or lemon to the water, and freezing a freezer-safe water bottle so there is always cold water available. Sharing tips with your patients may inspire them to drink more throughout their day.
Reevaluating Patient Risk
“Our study identified serum sodium levels above 142mmol/l as a risk factor for future development of heart failure and left ventricular hypertrophy,” Dmitrieva continues. “These levels are still within normal range (135–146 mmol/l) and, in current clinical practice, would not be flagged on the test results as abnormal. Based on our study, sodium levels above 142 mmol/l can be used by clinicians as a warning sign for identification of people with increased risk of heart failure and left ventricular hypertrophy.”
She adds that this doesn’t have to be an added test. Sodium is a standard test, part of a basic metabolic panel performed at every annual physical exam.
“Physicians can evaluate patients whose sodium level exceeds 142 mmol/l for the amount of liquids they drink, and, if found low, explain the risk and then advise them to drink recommended amounts of liquids,” Dmitrieva says. “In general, it would be beneficial to include in regular physical exams evaluation of drinking habits and counseling on appropriate amounts of fluids that people should drink.”
According to Dmitrieva, the recommendations for daily intake issued by different organizations vary from 2 to 3 liters for men and 1.6 to just over 2 liters for women. Worldwide surveys find that a large proportion of people do not meet even the lower ends of these ranges. This means that many people are chronically hypohydrated and will benefit from increasing their fluid intake.
Of course, recommending more fluids might go against the treatment plan for patients who have already been diagnosed with a disease such as heart failure, Dmitrieva says. “I would like to add a note of caution for recommending increase of fluid intake to patients with already diagnosed diseases and who are undergoing treatments for these diseases,” she says. “Some diseases, such as heart failure itself when it is already developed, require limiting fluid intake as a part of the treatment plan. For such patients, optimization of their fluid intake should be done with caution under supervision of the physician. Patients who are already undergoing treatment for existing diseases should consult with their doctors on their specific optimal fluid intake.”
Additional research will help shine light on the connection between heart health and hydration. That, Dmitrieva says, will help facilitate even better conversations about heart health and hydration.
“Further studies are needed to find out how exactly increased serum sodium leads to heart failure,” she explains. “Decreased hydration is one explanation and randomized, controlled trials would be necessary to obtain stronger evidence for decreased hydration as a major cause. For some people, in addition to hydration, serum sodium levels can increase due to other factors that are related to genetics, diseases, or medications. However, preventive measures based on these findings can be implemented immediately by reinforcing already existent recommendations for optimal water intake.”
— Lindsey Getz is an award-winning freelance writer in Royersford, Pennsylvania.