Why does blood pressure rise immediately after eating salty foods?

High blood pressure after eating salty food is usually caused by excessive intake, leading to increased circulating blood volume and arteriolar spasm. The specific mechanisms are as follows:

1. Increased Circulating Blood Volume

Salty foods typically contain high levels of sodium ions. Consuming salty foods may increase the concentration of sodium ions in the blood, resulting in elevated plasma osmotic pressure. This draws more fluid from the interstitial space into the blood vessels, increasing effective circulating blood volume and consequently raising blood pressure.

2. Arteriolar Spasm

In addition, following the above changes, the walls of small arteries may become more responsive to norepinephrine, angiotensin, and epinephrine in the bloodstream. This heightened reactivity can lead to arteriolar spasm, increasing resistance in the body's small arteries and causing blood pressure to rise.

After developing hypertension, it is recommended to adjust lifestyle habits under a doctor’s guidance and, if necessary, take antihypertensive medications to maintain blood pressure within the normal range.