We all know that salt is limited for patients with high blood pressure, then
why does salt help to increase high blood pressure(High Blood Pressure and Kidney Disease)?
★ Salt is abundant in sodium. If we ingest too much salt, then excessive
sodium will be detained in our body. Retention of sodium will inevitably cause
retention of water. Retention of great water and sodium will give rise to the
increase of fluid outside the cells, leading to the increase of blood
pressure.(High Blood Pressure and Kidney Disease)
★ Due to the concentration gradient, increased sodium outside cells will
cause the increase of sodium inside the cells. As a result, intracellular edema
appears. Edema of smooth muscle cell in small artery will lead to the narrowing
of lumen. Consequently, blood pressure increases.
★ Increase of sodium in cells can restrain the exchange of sodium and
potassium, leading to the increase of calcium. These calcium mainly get into
cells through susceptibility calcium channel. Increased calcium in the cells of
vascular smooth muscle cells will cause the shrink of smooth muscle, leading to
the increase of blood pressure.
★ Intake of too much sodium increases the receptor of type Ⅱ angiotensin.
Type Ⅱ angiotensin has strong ability of shrinking of blood vessels. Increase of
receptor of type Ⅱ angiotensin means the increase of type Ⅱ angiotensin. As a
result, high blood pressure appears.
★ Great amount of sodium can suscitate sympathetic nerve centre, causing the
increase of hypothalamus norepinephrine and then strengthen the stimulation to
hypothalamus neuron, which will increase the blood pressure.
★ Increase of sodium in presynaptic membrane cells of sympathetic nerve
ending will promote the release of norepinephrine. Norepinephrine often causes
the shrinking of blood vessels, and as a result, blood pressure increase.
Increasing blood pressure through ingesting too much salt is just one of the
methods. For patients with Chronic Kidney Disease, ingesting too much salt can
not only cause the increase of blood pressure, but also cause the aggravation of
swelling. Therefore, in their daily life, they should avoid ingesting too much
salt.