Question

How does salt increase blood pressure?

Answer 1

Salt in the diet ends up as increased salt in the blood. The blood volume then increases with the increased osmotic potential of the blood. This has an effect on venous return to the heart and increased cardiac output. However, having said all that, the blood pressure is usually controlled by the renin - angiotensin - aldosterone system so this would have to be overactive before an increase in blood pressure resulted.

http://en.wikipedia.org/wiki/Renin-angiotensin_system

I hope this helps - it's an interesting and important subject

Answer 2

Can you please explain it in simpler terms? I'm an O Levels student so don't need that much detail. O_o

Answer 3

OK, increased salt means the blood will draw water in through semi permeable membranes. These membranes include blood vessel linings so the blood volume increases. (an example of this process called osmosis is to take a chicken egg out of it's shell and put it in some water - it will swell up because of the salt and protein inside the egg). Simply put, the more blood volume the higher the pressure.

Renin is released in response to low blood volume, and it activates angiotensin which makes the blood vessels contract, increasing the pressure. Blood pressure is also controlled by the autonomic nervous system. This is why I said that these systems must be working overtime to increase blood pressure.

Answer 4

Thank you. I got it now. :D