Marcus, a college junior, has been sedentary since childhood. His maternal grandfather had a stroke in his 60s. Now, he wants to start high-intensity interval training. Marcus’s first step should be to

• A. Order a baseline resting electrocardiogram and a maximal exercise stress test to screen for hidden cardiac disease before any vigorous exercise.
• B. Complete a Physical Activity Readiness Questionnaire (PAR-Q) and follow American College of Sports Medicine (ACSM) risk guidelines, obtaining medical clearance only if needed.
• C. Begin supervised high-intensity interval training immediately to rapidly improve fitness, with careful monitoring and progression based on symptoms.
• D. Start a structured moderate-intensity endurance program for 8–12 weeks to build a fitness base before attempting high-intensity interval training.