The effect of habitual sustained endurance exercise on cardiac structure and function.

We performed echocardiographic evaluation of 20 male veteran endurance runners (mean age 56 +/- 7 years) and compared them with a group of age-matched controls. All the runners had run at least 25 miles per week for more than 25 years. Although only four athletes showed voltage ECG evidence of left ventricular hypertrophy, using echocardiography, 10 athletes had evidence of left ventricular hypertrophy. Thus electrocardiography is insufficiently sensitive to detect LVH in this group (10%). Left ventricular posterior wall thickness and left ventricular mass were significantly greater in the athletes, the difference becoming more marked when LV mass was corrected for body surface area and, consequently, the wall thickness: cavity diameter ratio was increased (P less than 0.04). There was no difference between the two groups in left ventricular performance and no correlation between left ventricular mass and running ability. Thus, veteran runners develop structural cardiac changes similar to younger power-trained athletes and do not show characteristics normally expected of 'volume overload' which is thought to occur in running.