In order to clarify the left ventricular (LV) bemodynamic change at extreme exercise, 6 male cross country racers underwent stress echocardiography with an upright bicycle ergometer. The heart rate (HR) achieved was 187±8.6 bpm, or 94.1%±4.5% of target rate. During exercise, stroke volume (SV) index (mL/m2) showed significant increase from resting (T0) to the time when the HR achieved 120 bpm (T120), and from T120 to the time when the HR reached 150 bpm (T150) (T0:T120:T150=49±6:69±11:92±6; T0 vs. T120, p120 vs. T150, p150 vs. T(max), p2) significantly increased when HR approached T150 and bit the ceiling limit (T0: T120: T150' T(max)= 2.86 ± 0.77:8.3 2 ± 1.30: 13.80±1.85:14.67±2.21; T0 vs. T120, p120 vs. T150 p150 vs. T(max) p=0.48). No significant difference in ejection fraction was observed. Results suggest that cardiac output of cross country racers reaches the ceiling before extreme exercise, and this is caused by the decrease of SV. Shortened filling period caused by tachycardia is thought to induce a decline in LV volume at extreme exercise.
|Number of pages||4|
|Journal||Journal of Noninvasive Cardiology|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Radiology Nuclear Medicine and imaging