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Cardiac output and left ventricular function in response to exercise in older men
S G Thomas1, D H Paterson, D A Cunningham
1Centre for Activity and Ageing, London, Ont., Canada.
Canadian Journal of Physiology and Pharmacology
|February 1, 1993
Summary
Cardiovascular response in older men shows minimal decline during exercise. Cardiac output and stroke volume changes are less pronounced, but left ventricular function remains largely preserved.
Area of Science:
- Cardiovascular Physiology
- Exercise Science
- Gerontology
Background:
- Conflicting data exists on cardiovascular response to exercise in older adults.
- Previous studies show varied results on left ventricular function and cardiac output-oxygen consumption relationships.
Purpose of the Study:
- To investigate the cardiovascular response to submaximal and strenuous exercise in older men.
- To clarify changes in cardiac output, stroke volume, and left ventricular function during exercise in aging.
Main Methods:
- Evaluated 96 men (mean age 63) during incremental treadmill exercise, measuring cardiac output (Q) via CO2 rebreathing.
- Assessed 12 subjects during supine exercise using radionuclide angiocardiography for left ventricular volumes.
Main Results:
- Treadmill exercise showed lower Q (~10%) and a lower Q-VO2 relationship intercept compared to younger individuals.
- Stroke volume plateaued or slightly declined at high workloads; peak arteriovenous O2 difference approached younger values.
- Supine exercise revealed increased stroke volume due to reduced end-systolic volume, with stable end-diastolic volume and increased ejection fraction.
Conclusions:
- Older men exhibit only minor reductions in cardiovascular response and left ventricular performance during exercise.
- Findings contrast with some reports, suggesting better-preserved cardiac function in aging than previously thought.