Systolic pressure (first phase) is identified with the first of the continuous Korotkoff sounds.

A systolic pressure of 40 mm Hg typically implies a mean pressure of more than 25 mm Hg.

Blood pressure is summarised by two measurements, systolic and diastolic, which depend on whether the heart muscle is contracting (systole) or relaxed between beats (diastole).

Blood pressure rises with age in childhood and, in children, hypertension is defined as an average systolic or diastolic blood pressure on three or more occasions equal or higher than the 95th percentile appropriate for the sex, age and height of the child.

(the result is H(G(F(X)))), then this can be expressed as a distributed memory problem where the data is transmitted first to the node that performs F that passes the result onto the second node that computes G, and finally to the third node that computes H. This is also known as systolic computation.