GENDER-RELATED DIFFERENCES IN LEFT-VENTRICULAR FILLING DYNAMICS IN OLDER SUBJECTS AFTER ENDURANCE EXERCISE TRAINING

The present study was designed to determine if gender affects the adap tive response to endurance exercise training of left ventricular filli ng dynamics in older individuals. Recently, it was shown that gender i nfluences the cardiovascular responses to endurance exercise training in older subjects. Older men improve left ventricular systolic perform ance and increase maximal cardiac output in response to endurance exer cise training, whereas older women do not. Twelve men (65+/-1 years ol d; mean+/-SE) and 10 women (64+/-1) were studied before and after 9 mo nths of endurance exercise training. Maximal O-2 uptake was determined during treadmill exercise. Left ventricular filling dynamics and ejec tion fraction (EF) at rest and during supine exercise were assessed by Tc-99m radionuclide ventriculography. When expressed relative to body weight, maximal O-2 uptake (Vo(2) max) was increased by 24% (27.3+/-1 .5 to 34.0+/-1.5 ml/kg/min; p <.01) in men and 27% (21.9+/-1.0 to 27.8 +/-1.0 ml/kg/min; p <.01) in women in response to endurance exercise t raining. In men, the time-to-peak filling rate (TPFR) decreased (-19.8 +/-6.7 ms; P <.05) during exercise at a comparable heart rate in respo nse to training. In contrast, the change in TPFR in women (+2.7+/-6.0 ms) was small and insignificant. Peak filling rate (PFR) at rest and d uring exercise was similar before and after training in men and women. The change in left ventricular systolic reserve at a comparable heart rate from pre- to posttraining improved in men (Delta Ef 4+/-3%; p <. 05), but not in women (-2+/-3%). The results indicate that the adaptiv e response of left ventricular filling dynamics to endurance exercise training is influenced by gender in older subjects. Older men show imp rovement in left ventricular filling dynamics, whereas older women do not.