We assessed left ventricular systolic and diastolic performance during and after prolonged exercise under controlled conditions in a group of healthy, trained men. Previous studies have examined the effects of prolonged effort on left ventricular function, yet it remains unclear whether or not left ventricular dysfunction (e.g. cardiac fatigue) can be produced under such conditions. We studied 15 healthy men, aged 27±1 years (mean±S.E.M.). Subjects exercised on bicycles at a constant work rate (60% of maximum oxygen uptake per min) for 150 min. Measurements of gas exchange, blood pressure and haematocrit were obtained, concurrent with the assessment of left ventricular function using equilibrium radionuclide angiography, at rest, during exercise (every 30 min) and after 30 min of recovery. Fluid replacement was provided and monitored during the exercise period. The baseline resting and exercise ejection fractions were 66±2% and 78±2% respectively. During exercise, subjects consumed 1816±136 ml of fluid, and the haematocrit had increased at 120 min of exercise (from 47.2%±0.6 to 49.9±0.8%; P < 0.05). There was no change in either systolic or diastolic blood pressure throughout the exercise period, but heart rate drifted upwards from 141±2 beats/min after 30 min to 154±3 beats/min after 150 min (P < 0.05). There was a small decline (8%; P < 0.05) in end-diastolic volume at 150 min. No changes were observed in left ventricular ejection fraction, the pressure/volume ratio or end-systolic volume. After 30 min of sitting in recovery, heart rate was still higher than the pre-exercise value (84±3 compared with 69±2 beats/min; P < 0.05), as were measures of peak filling rate and time to peak filling (P < 0.05). The ejection fraction in the post-exercise recovery period was similar to the pre-exercise value. The results indicate that prolonged exercise of moderate duration may not induce abnormal left ventricular systolic function or cardiac fatigue during exercise.
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May 2001
Research Article|
April 09 2001
Left ventricular performance during prolonged exercise: absence of systolic dysfunction
Jack M. GOODMAN;
*Faculty of Physical Education and Health, University of Toronto, 55 Harbord Street, Toronto, Ontario, Canada M5S 2W6
Correspondence: Dr Jack M. Goodman (e-mail jack.goodman@utoronto.ca).
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Peter R. McLAUGHLIN;
Peter R. McLAUGHLIN
†Heart & Stroke/Richard Lewar Centre of Excellence, Faculty of Medicine, University of Toronto, 150 College Street, rm 8, Fitzgerald Building, Toronto, Ontario, Canada M5S 3E2
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Peter P. LIU
Peter P. LIU
†Heart & Stroke/Richard Lewar Centre of Excellence, Faculty of Medicine, University of Toronto, 150 College Street, rm 8, Fitzgerald Building, Toronto, Ontario, Canada M5S 3E2
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Clin Sci (Lond) (2001) 100 (5): 529–537.
Article history
Received:
June 13 2000
Revision Received:
November 27 2000
Accepted:
February 01 2001
Citation
Jack M. GOODMAN, Peter R. McLAUGHLIN, Peter P. LIU; Left ventricular performance during prolonged exercise: absence of systolic dysfunction. Clin Sci (Lond) 1 May 2001; 100 (5): 529–537. doi: https://doi.org/10.1042/cs1000529
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