What causes an increase in systole bp during exercise and furthermore what would cause an abnormal increase?

Answer 1

The increase of systole pressure is simply do to the increased heart activity and the response by the muscles and organs in the body to the increase.

An abnormal increase would likely happen if someone had problems with the the adrenal gland where it released too much aldosterone. Increasing aldosterone increases the osmotic pressure in the blood. Drugs and stress (all types of stress) can affect the adrenal gland.

Other abnormal increases can occur from the intake of too many liquids before the kidneys can process it all. Being hooked up to an IV can also increase bp, especially if done improperly.

Answer 2

Systolic blood pressure is most sensitive to changes in diastolic return, which is the amount of blood returning to the ventricles during diastole. This results in a larger stroke volume, which means more pressure builds up when it is ejected (systole). During exercise, systemic vascular resistance drops considerably (due to arteriolar dilation in skeletal muscles), which increases flow and thus diastolic return. Also, veins tend to constrict, which helps move their blood volume to the heart better, which again boosts diastolic return.

An abnormal increase in systolic blood pressure can arise from anything that increases stroke volume. Some examples off the top of my head are a large IV infusion, laying down suddenly, an AV blockage, or a shunt of some kind would all cause a boost to systolic pressure but not as much to diastolic. Of course, things like chronic hypertension, or anxiety, would boost both systolic and diastolic pressure.