Final answer:
During a maximal exercise test, a healthy adult is expected to experience an increase in systolic blood pressure as cardiac output increases to meet the body's oxygen demands. However, if the heart rate exceeds 160 bpm, the cardiac output will eventually decrease due to reduced stroke volume. The correct option is B.
Step-by-step explanation:
During a maximal incremental exercise test in a healthy adult with a resting BP of 120/80, one would expect to see an increase in systolic blood pressure (b). This is because as exercise intensity increases, cardiac output (the product of heart rate and stroke volume) also increases to meet the higher demand for oxygen by the body's tissues.
Specifically, when heart rate increases above 160 beats per minute (bpm), cardiac output initially rises but will eventually decrease as heart rate continues to increase, due to a reduction in stroke volume from decreased ventricular filling time.
In general, the body's physiological response to exercise also includes an increased minute respiration (a) and a decrease in intestinal peristalsis (b), whereas the blood's oxygen saturation typically remains relatively stable or can increase due to more efficient pulmonary function during exercise.