Donating blood can lower blood pressure. Even significantly.
This of course has been published in various studies, including on Greyhounds and regarding the donation of plasma.
Of course, there are Benefits of Donating Blood which is why bloodletting was so popular for thousands of years as overall it did carry benefits.
Bloodletting is still done. It is rarely being done, but here is one example of it still taking place:
Can’t believe that it’s legal. Doesn’t seem very healthy treatment. Who knows.
I am B-. I’ve always had a lower than normal blood pressure and recently donated blood for the first time.
I had no problem with my blood pressure but they did have a problem with taking my blood because of clotting.