Heart size and function of soldiers, athletes, and sedentary men

This study compares the heart sizes and left ventricular masses of soldiers (n = 11) with age- and body size-matched groups of sedentary men (n = 10) and accomplished athletes (n = 11). Echocardiography revealed that active duty soldiers (A) who met minimal fitness standards and pentathletes (P) had greater average left ventricular (LV) end-diastolic volumes (A = 10%, NS; P = 28%, p < 0.05), stroke volumes (A = 29%, NS; P = 44%, p < 0.01), and LV masses (A = 22%, NS; P = 76%, p < 0.01) than sedentary subjects. Athletes had an average LV wall thickness which was 23% (p < 0.05) greater than that of soldiers and 32% (p < 0.01) greater than that of sedentary men. The LV wall thickness to radius ratio (h/r) was similar between soldiers and sedentary men, but in athletes the h/r was greater (p < 0.01) than in the less conditioned subjects. These data suggest that soldiers who meet minimal standards of fitness exhibit cardiac morphometric features consistent with endurance conditioning. However, the soldiers studied were significantly less (p < 0.001) conditioned than the competitive athletes. These data suggest that improvements in aerobic and cardiac conditioning could be achieved through a greater emphasis on physical training.