Endurance training left ventricular adaptations.

• A. Decreased LV wall thickness
• B. Increased chamber size with decreased wall thickness
• C. Smaller chamber with thicker wall
• D. Increased LV wall thickness and larger chamber

Answer: (D)

Endurance training causes eccentric hypertrophy of the left ventricle due to chronic volume overload, so the heart adapts by enlarging the chamber to hold more blood and adding some wall thickness to support the greater volume. This combination reduces wall stress while increasing stroke volume and overall cardiac output during aerobic exercise. The best choice reflects both a larger LV chamber and thicker wall, capturing the dilation and mild hypertrophy that come with endurance adaptations. Options that suggest a smaller chamber with a thick wall or a dilated chamber with thinner walls describe other patterns (concentric hypertrophy from strength training or pathological dilation) and don’t match the endurance remodeling pattern.