When does systolic blood pressure typically increase?

Systolic blood pressure reflects the pressure in the arteries when the heart beats and pumps blood. It typically increases during left ventricular contraction, which is also known as systole. When the left ventricle contracts, it forces blood into the aorta and creates a pulse wave, resulting in increased pressure within the arterial system. This surge of pressure is what is measured as systolic blood pressure.

During relaxation of the heart, also known as diastole, blood pressure decreases. At rest, blood pressure can stabilize or decrease depending on various factors, without any active contraction contributing to an increase. Deep breathing can have a minor impact on blood pressure regulation through changes in vagal tone and pressure changes in the thoracic cavity, but it does not cause a significant increase in systolic blood pressure like left ventricular contraction does. Hence, the increase in systolic blood pressure is specifically associated with the period of contraction of the left ventricle.