If blood means sangre, and bleed sangrar, bloody will mean sangriento, the adjective. Also it means, violento and in some other occasions it means maldito, condenado, pinche, jodido and the UK it is utilised as intensifier adjectives, muy and tan.
I don't know the length of the blood vessels, it is incredible 100,000 miles. It is real that the blood is very important in human health, and without it we can't live.
The most important for a healthy heart is not to drink alcohol and eat less salt (5g per day). Sometimes there are problems which are hereditary, and so these people must be more careful and these cares have to be better.
There are a lot of stories about the blood from the Roman to the famous vampire Dracula. I don't believe them, because the youth of the face doesn't depend on the blood, but in the aging process of the person.