Why Salt May Spike Your Blood Pressure

Too much sodium, or salt, can raise blood pressure to dangerous levels. But until now, researchers haven't really known why.

It's also unusual that some people can consume large amounts of sodium with little or no effect, while others appear to be extremely sensitive to foods containing salt. 

New research from Case Western Reserve University School of Medicine and Kent State University shows that salt intake raises blood pressure because it makes it harder for the cardiovascular system to simultaneously juggle the regulation of blood pressure and body temperature.

The inability to understand why salt raises blood pressure in some individuals but not others has hampered the development of a comprehensive theory as to what causes most cases of high blood pressure. More importantly, it may have prevented more effective treatments.

Lower body temperature

In a series of tests, the researchers discovered that drinking salt water lowered body temperature in men more than drinking water by itself. They also found that body temperature decreased more in individuals who are salt resistant than in individuals who are salt sensitive.

"It appears that salt sensitive individuals maintain core body temperature equilibrium more effectively than salt resistant individuals, but experience increased blood pressure in the process," said Robert P. Blankfield, MD, MS, clinical professor of family medicine at Case Western Reserve University School of Medicine. "Conversely, salt resistant individuals maintain blood pressure equilibrium more effectively than salt sensitive individuals following salt and water intake, but experience a greater temperature reduction in the process."

The fact that researchers think they have unlocked the key to hypertension in salt-sensitive patients, they think it may lead to the discovery of what causes high blood pressure in general. That, in turn, could lead to more effective treatments for the chronic condition.

Hypertension affects an estimated one in four American adults and is a leading contributor to heart attacks and stroke.