Which statement best describes physiologic cardiac hypertrophy due to exercise?

Which statement best describes physiologic cardiac hypertrophy due to exercise?

• A. Includes extensive fibrosis
• B. Involves an increase in myocyte length more than width
• C. Primarily affects the right ventricle
• D. Is associated with reduced capillary growth

Answer: (B)

Exercise-induced physiologic hypertrophy is an adaptive heart enlargement where the heart remodels by adding sarcomeres in series, making the cardiomyocytes longer rather than wider. This elongation of cells leads to modest chamber enlargement with preserved or enhanced function and without the fibrosis seen in disease. Capillary growth tends to keep up with the increased muscle, supporting the higher metabolic demand. That’s why the statement about myocyte length increasing more than width best captures the nature of physiologic hypertrophy from exercise. In contrast, hypertrophy driven by pathology usually involves adding sarcomeres in parallel (increasing wall thickness) and is associated with fibrosis and impaired capillary balance, and it doesn’t tend to be limited to the right ventricle.

Exercise-induced physiologic hypertrophy is an adaptive heart enlargement where the heart remodels by adding sarcomeres in series, making the cardiomyocytes longer rather than wider. This elongation of cells leads to modest chamber enlargement with preserved or enhanced function and without the fibrosis seen in disease. Capillary growth tends to keep up with the increased muscle, supporting the higher metabolic demand.

That’s why the statement about myocyte length increasing more than width best captures the nature of physiologic hypertrophy from exercise. In contrast, hypertrophy driven by pathology usually involves adding sarcomeres in parallel (increasing wall thickness) and is associated with fibrosis and impaired capillary balance, and it doesn’t tend to be limited to the right ventricle.