Scenario 10 | Cardiac Stress Test A 22-year-old competitive…
Scenario 10 | Cardiac Stress Test A 22-year-old competitive cyclist undergoes a graded exercise test. As workload increases, her heart rate and stroke volume rise to meet the increasing demands of working skeletal muscle, resulting in a progressive increase in cardiac output. Blood flow is preferentially redistributed to active muscles, while venous return increases due to the skeletal muscle pump. At higher intensities, she begins to experience muscle fatigue and reports a progressive decline in force generation in her leg muscles. Despite continued neural drive, her muscles are less able to sustain powerful contractions. Her heart rate approaches its maximum, and stroke volume begins to plateau. She also reports a sensation of heaviness and reduced coordination in her legs. As exercise continues near maximal effort, she becomes lightheaded and experiences occasional muscle cramping. Her blood pressure regulation becomes more variable, and she has difficulty maintaining consistent pedal force. After stopping exercise, her heart rate and ventilation remain elevated for several minutes as her cardiovascular system gradually returns to baseline.