Peter Attia· MD
so when your left ventricle contracts you're in in systole blood is leaving the heart through the aortic valve goes out the aorta at the ascending part of the aorta and then it immediately just starts moving to the rest of the body right so at the arch of the aorta it jumps off three little freeways if you will right so you have the common carotid subclavian and ominous arteries and then it kind of goes over the arch comes down and then it goes out to the rest of the body right so there's a pressure in the artery that is experienced by literally the blood pushing against the walls of the artery during that phase and that's obviously the bigger number but it's important to remember that there is a second equally important phase of the heart which is the relaxation of The ventricle and that's how they fill so that's called diastole so after the heart squeezes and blood leaves the heart the heart has to relax to have Blood come back into the ventricles through the Atria