Thirst Trap

Forgetting to drink enough water could have a serious impact on your heart

In a study, one sign of low bodily fluids increased the risk of heart failure by almost half.

People's shadows during a sunset, drinking water
Bill Gentile/The Image Bank Unreleased/Getty Images

It’s the simplest of health advice: Drink plenty of water. A well-hydrated body is better at digesting food, carrying nutrients and oxygen to cells, stabilizing the heartbeat and blood pressure, and regulating body temperature.

Maintaining a decent level of bodily fluids may also slow or prevent deterioration of the heart, according to a study published last month in the European Heart Journal.

Researchers used data from more than 5,000 people collected over 25 years. Those who had a higher level of a biomarker showing chronically low levels of bodily fluids in middle age were much more likely to — over the next 25 years — suffer heart failure as well as a dangerous thickening of the wall of the heart’s primary pump.

Science In Action — When we are low in fluids, the body kicks into a water preservation mode that strains the heart, Natalia Dmitrieva, lead study author and a National Institutes of Health researcher, tells Inverse.

LONGEVITY HACKS is a regular series from Inverse on the science-backed strategies to live better, healthier, and longer without medicine. Get more in our Hacks index.

The process constricts blood vessels and decreases blood volume, so “the heart has to work harder to pump blood,” Dmitrieva wrote in an email to Inverse.

To investigate this impact, she and her authors examined data from the long-running Atherosclerosis Risk in Communities (ARIC) study.

In the 1980s, ARIC recruited 15,792 people in four U.S. cities to provide reports of their health for decades so that researchers could someday mine them for data that might show correlations between certain health traits and heart disease. The volunteers were aged 44 to 66 at the start of the study.

The process constricts blood vessels and decreases blood volume, so “the heart has to work harder.”

In addition to phoning in information about their health every year, the volunteers periodically went to study sites where researchers took health measurements.

One test they took was for serum sodium, the amount of sodium in the blood. Serum sodium levels rise when the body is lacking water and when its fluid levels diminish without being replaced. It’s a sure sign that the person hasn’t been drinking as much water as their body needs.

The researchers looked at the serum sodium levels at the first two visits of 5,162 people and then traced their cardiovascular health over the years. They excluded people with conditions that might affect their levels.

If the average serum sodium level of their first two check-ins exceeded 143 millimoles per liter, their risk of an episode of heart failure over the years was 39 percent higher. With every additional millimoles per liter, the risk of heart failure budged by five percent.

People with lower serum solution levels were less likely to have signs of thickening of the left ventricle (highlighted)


Those serum sodium levels were also associated with a 107-percent increase in the odds the person was later diagnosed with left ventricular hypertrophy, a thickening of the walls of the heart’s main pumping chamber.

Those levels are in the high end of the normal range, a sign the person hasn’t been drinking enough water but not so high they indicate some other factor that impacts sodium levels (diabetes, steroid use, a ridiculously salty diet).

This is all to say that signs a person was not drinking enough water were tied to serious consequences for their cardiovascular health.

How This Affects Longevity — Heart disease is the leading cause of death in the U.S., accounting for one in four deaths. It’s the leading killer of both men and women and the top cause of death among most ethnic groups. Of course, the risk of death from a heart attack increases with age, with 66 percent of those deaths occurring in people age 75 and older.

If you want to live to the age of, say, an average U.S. Senator, heart health is a critical factor.

Dmitrieva adds, “[O]ur results are directly relevant to people starting at 45 years. Our study does not provide evidence for younger people. However, it would be safe to advise people of all ages to follow recommendations on healthy fluid intakes.”

Why It’s a Hack — The study authors came out of their data crunch with the following recommendations: 6 to 8 cups (1.5-2.1 liters) of fluids a day for women and 8 to 12 cups (2-3 liters) for men. This is south of the guidelines of the U.S. National Academies of Sciences, Engineering, and Medicine, of 2.7 liters for women and 3.7 liters for men. There’s no argument that keeping up a water consumption habit of about that range has multifaceted health benefits.

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