Science 30 January 1999 Grade 12 Diploma Examination

Long Answer – 15%1. Many scientists have suggested that there is a link between levels of blood pressureand regular exercise. A group of Science 30 students developed the prediction thatstudents who exercise regularly would experience a smaller increase in bloodpressure after exercise compared with students who do not exercise regularly. Thefollowing experiment was designed to test their hypothesis.Group 1 consisted of six male students aged 16 to 19 who were members of theschool’s basketball team. Group 2 consisted of six students who did not exerciseregularly. The systolic blood pressures of all of these students were measured andrecorded when the students were at rest. Their systolic blood pressures weremeasured again immediately after the students ran 5 laps of the gymnasium. Thefollowing is a graph of the data obtained.Effect of Exercise on Blood PressureAverage systolic blood pressure (mm Hg)200150100500Before exercise After exerciseActivity levelGroup 1Group 2a. Describe two ways in which the body controls blood pressure.......................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................30