Abstract
Aim To determine whether the larger exercise stroke volume in senior endurance-trained athletes results from an attenuation of age-related alterations in left ventricular (LV) early diastolic filling or a more vigorous late filling. Methods Body composition (DEXA), VO2peak, stroke volume (CO2 rebreathing) and Doppler measures of early and late mitral inflow and mitral annular velocities were collected at seated upright rest and heart ratematched exercise (100 and 120 bpm) in trained and untrained younger (1830 years) men and trained and untrained older (6080 years) healthy men. Results Ageing had a greater effect than training status on seated rest mitral inflow and tissue Doppler imaging parameters, as shown by a lower peak early-to-late mitral inflow velocity ratio (E/A ratio) and slower peak early mitral annular velocity (Em) in older compared with younger men. Exercise stroke volume was unaffected by healthy ageing; however, Em, an index of early LV lengthening rate and relaxation, was slower (P < 0.001), while measures of atrial systole were increased (P < 0.001) during exercise in older men. Stroke volume during exercise was larger in the trained men (P < 0.001); however, early and late mitral inflow and tissue velocities were not different between trained and untrained men. Conclusion The larger exercise stroke volume in trained older male athletes does not seem to be related to faster filling or lengthening velocities during early or late filling. Thus, a larger, more compliant left ventricle in combination with an increased blood volume may explain the larger LV filling volumes in trained seniors.