Your blood pressure is reported as, say 140/60. The top number is the systolic number, and the bottom number is the diastolic number. The systolic number reflects how hard the heart has to work to push blood out into the aorta (main artery in the trunk), and then to the rest of the body. It reflects hardening of the arteries as well. If the number creeps up to 180 or 190 or 200, your dr. Would probably talk to you about having tests to see if you have peripheral arterial occlusive disease, or "hardening of the arteries"
Systolic pressure means that it is when the heart contracts to get the first number when getting a blood pressure. That is when your heart is forcing blood Thur the aorta to get to the lungs for oxygenation.