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Cardiac output decline in prolonged dynamic exercise is affected by the exercise mode
George P Nassis1, Nickos D Geladas
1Department of Sport Medicine and Biology of Physical Activity, Faculty of Physical Education and Sport Science, University of Athens, 41 Ethnikis Antistassis Street, 172 37, Daphne, Greece. ngeladas@cc.uoa.gr
Pflugers Archiv : European Journal of Physiology
|December 6, 2002
Summary
Cardiovascular responses differ between prolonged cycling and running. Stroke volume and cardiac output declined more in cycling, despite lower dehydration and body temperature compared to running.
Area of Science:
- Exercise Physiology
- Cardiovascular Physiology
Background:
- Understanding cardiovascular strain during different exercise modalities is crucial for optimizing training and performance.
- Prolonged submaximal exercise elicits significant physiological adaptations, including changes in cardiac output and stroke volume.
Purpose of the Study:
- To compare the cardiovascular responses, specifically cardiac output and stroke volume, during prolonged submaximal cycling versus running.
- To investigate the influence of dehydration and hyperthermia on these cardiovascular responses.
Main Methods:
- Eleven healthy males completed two 90-minute sessions of cycling and running at 60% of their mode-specific maximal oxygen uptake (VO2max).
- Cardiovascular parameters, including cardiac output, stroke volume, heart rate, and skin blood flow, were measured.
- Body temperature and hydration levels were monitored throughout the exercise protocols.
Main Results:
- Cardiac output significantly declined after 85 minutes of cycling but not running.
- Stroke volume decreased more substantially during cycling (-22.7 ml/beat) compared to running (-14.3 ml/beat).
- These declines occurred despite greater dehydration and higher rectal temperature in the running trial.
Conclusions:
- Stroke volume and cardiac output reductions are more pronounced during prolonged submaximal cycling than running.
- These differences persist even with lower levels of dehydration and hyperthermia during cycling.
- The findings highlight distinct cardiovascular regulation strategies between cycling and running.