BACKGROUND: Stroke volume (SV) in trained athletes continuously increases with progressive exercise intensity. We studied whether physical training affected left ventricle (LV) function response to exercise using 3D echocardiography and tissue Doppler imaging (TDI). METHODS: Eleven male university athletes and 12 male university nonathletes were enrolled in this study. After baseline data were collected, subjects performed a symptom-limited supine bicycle ergometer exercise test. Initial workload was 25 Watts (W) and increased 25 W every 3 minutes. At rest and every exercise stage, LV end-systolic and diastolic volume index (LVEDVI and LVESVI), SV index (SVI), cardiac index (CI), LV ejection fraction (LVEF), and early lateral mitral flow velocity (Ea) were evaluated. Heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) were continuously recorded. RESULTS: Nonathletes showed a slow increase in CI, and SVI reached a plateau value at a HR of 90 beats per minute (bpm). In contrast, CI and SVI increased progressively and continuously in athletes. Both CI and SVI were significantly higher in athletes than in nonathletes at HRs of 100, 110, and 120 bpm. LVEDVI kept increasing in athletes while it plateaued in nonathletes. In contrast, LVESV decreased continuously during exercise in both groups. There was no significant difference in LVEF, Ea, SBP, or DBP at rest and during exercise between the two groups. CONCLUSION: LV responses to exercise in athletes were different from those of in nonathletes; thus, habitual physical training may play an important role in the increase in both SVI and CI in young individuals.
BACKGROUND:Stroke volume (SV) in trained athletes continuously increases with progressive exercise intensity. We studied whether physical training affected left ventricle (LV) function response to exercise using 3D echocardiography and tissue Doppler imaging (TDI). METHODS: Eleven male university athletes and 12 male university nonathletes were enrolled in this study. After baseline data were collected, subjects performed a symptom-limited supine bicycle ergometer exercise test. Initial workload was 25 Watts (W) and increased 25 W every 3 minutes. At rest and every exercise stage, LV end-systolic and diastolic volume index (LVEDVI and LVESVI), SV index (SVI), cardiac index (CI), LV ejection fraction (LVEF), and early lateral mitral flow velocity (Ea) were evaluated. Heart rate (HR), and systolic and diastolic blood pressure (SBP and DBP) were continuously recorded. RESULTS: Nonathletes showed a slow increase in CI, and SVI reached a plateau value at a HR of 90 beats per minute (bpm). In contrast, CI and SVI increased progressively and continuously in athletes. Both CI and SVI were significantly higher in athletes than in nonathletes at HRs of 100, 110, and 120 bpm. LVEDVI kept increasing in athletes while it plateaued in nonathletes. In contrast, LVESV decreased continuously during exercise in both groups. There was no significant difference in LVEF, Ea, SBP, or DBP at rest and during exercise between the two groups. CONCLUSION: LV responses to exercise in athletes were different from those of in nonathletes; thus, habitual physical training may play an important role in the increase in both SVI and CI in young individuals.