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Effect of isotonic exercise training on left ventricular volume during upright exercise
Circulation
|December 1, 1985
Summary
Highly trained runners utilize the Frank-Starling mechanism more during exercise, showing larger left ventricular volumes. This contrasts with less trained runners who exhibit greater increases in systolic blood pressure to end-systolic volume ratio.
Area of Science:
- Cardiology
- Exercise Physiology
- Sports Science
Background:
- Understanding cardiac adaptations to exercise is crucial for athletes.
- Left ventricular (LV) function changes significantly during physical exertion.
Purpose of the Study:
- To investigate changes in left ventricular volume and their temporal course during graded exercise.
- To compare cardiac responses between competitive marathon runners and less trained runners.
Main Methods:
- Utilized biapical two-dimensional echocardiography to measure LV end-diastolic and end-systolic volumes during bicycle exercise.
- Validated echocardiographic technique against gated equilibrium radionuclide angiography in a subset of patients.
- Correlated resting LV end-diastolic volume with maximal exercise endurance time.
Main Results:
- LV end-diastolic volume, stroke volume, and ejection fraction increased during exercise, primarily in the first half.
- Systolic blood pressure/end-systolic volume (SBP/ESV) increased, with the largest change in the second half of exercise.
- Competitive marathon runners had larger resting LV volumes and greater increases in end-diastolic volume during exercise compared to non-competitive runners.
Conclusions:
- Highly trained runners rely more on the Frank-Starling mechanism for exercise performance.
- Differences in LV volume dynamics and SBP/ESV response distinguish competitive from less trained runners during exercise.