Circulatory interview?

Im getting a little confused:
According to cardiac function curve, if you increase cardiac output you dwindling central venous pressure? Can someone please explain please. thats what would take place in a tough individual because of peripheral vasodilatation.
surrounded by sick people the vessel arent as elastic so the heart rate go up, and the vessels calibre stays like peas in a pod so their pressure goes up.
I can't explain it any but I saw it with my own eyes. during a stress trial the more the patients heart rate went up the lower his B/Pwas.
more output medium the CENTRAL venous pressure is less because smaller number blood in the heart!