Hydration and Blood Pressure: Surprising Facts on Fluid Intake and Your Health

Fluid retention is a major contributing factor to hypertension, or high blood pressure. Properly hydrating during these intensely hot days is an obvious necessity to prevent heat exhaustion or life-threatening heat stroke. But clinical studies also indicate a relationship between blood pressure and hydration status.

For those with underlying health issues, including hypertension, maintaining proper fluid levels at all times is very important. Public health agencies generally recommend that people with healthy hearts and kidneys consume 2.7 to 3.7 liters of water per day. However, the average U.S. adult only drinks about 41 ounces of water per day, or 1.2 liters.

Of course, suggested water intake for healthy adults varies, depending on several factors including age, gender, body weight, activity level, and the weather. Exercising or working outdoors in South Florida, for example, requires more fluid intake to beat the heat and humidity.

Ian Del Conde, M.D., director of the Vascular Medicine Program and the Resistant Hypertension Clinic at Baptist Health Miami Cardiac & Vascular Institute.

 

Dehydration occurs when the body loses more water than it takes in, which can lead to an imbalance in electrolytes and fluids. Being dehydrated can both lower and raise blood pressure levels, explains Ian Del Conde, M.D., a cardiologist and vascular medicine specialist at Baptist Health Miami Cardiac & Vascular Institute.

“When you become dehydrated, your blood volume decreases, which can initially lead to a drop in blood pressure,” Dr. Del Conde. “However, as the body tries to compensate, it releases certain hormones that can constrict blood vessels and cause blood pressure to rise. This means dehydration can paradoxically result in both low and high blood pressure.”

The National Institutes of Health (NIH) found a “strong association between hypertension status and hydration parameters” in a study released in 2022. “This outcome should raise awareness about proper hydration as hypohydration can be a causative factor for hypertension,” the NIH said. Hypohydration is a state when the body carries less water than normal daily fluctuations.

In a separate study released in 2023, the NIH found that “adults who stay well-hydrated appear to be healthier, develop fewer chronic conditions, such as heart and lung disease, and live longer compared to those who may not get sufficient fluids.”

Hydration status is just one factor that may impact blood pressure. Along with maintaining a healthy hydration status, Dr. Del Conde advises that the following habits may positively affect a person’s blood pressure.

• Maintaining a healthy weight;
• Participating in regular exercise;
• Reducing sodium intake;
• Limiting alcohol consumption;
• Managing stress.
• Incorporating foods rich in potassium, magnesium, and fiber.

A recently published study found that practically everyone can lower their blood pressure by lowering their sodium intake (primarily from salt), even if they are currently on blood pressure-reducing drugs. The study, published in JAMA, found that 72 percent of study participants experienced a lowering of their systolic blood pressure on the low-sodium diet compared with their usual diet.

“Sodium (or salt) intake has been well-established to have an impact on blood pressure,” said Dr. Del Conde. “Some individuals have a more salt-sensitive high blood pressure and others. Having said that, anyone with high blood pressure should get used to not adding additional salt to food.”