Abstract
Orthostatic intolerance may result from either an abnormally large postural decrease in central blood volume, cardiac filling pressures, and stroke volume, or inadequate neurohumoral responses to orthostasis. Endurance athletes have been reported as having a high incidence of orthostatic intolerance, which has been attributed primarily to abnormalities in barorefiex regulation of heart rate and peripheral resistance. In this review, we present evidence that athletes also have structural changes in the cardiovascular system that although beneficial during exercise, lead to an excessively large decrease in stroke volume during orthostasis and contribute to orthostatic intolerance. A unifying hypothesis based on cardiac mechanics that may explain the divergence of findings in conditions such as bed rest or spaceflight, and short- and long-term endurance training is presented.
Original language | English (US) |
---|---|
Pages (from-to) | 727-732 |
Number of pages | 6 |
Journal | Medicine and science in sports and exercise |
Volume | 25 |
Issue number | 6 |
State | Published - Jun 1993 |
Keywords
- Central blood volume
- Diastolic function
- Endurance athletes
- Frank-starling mechanism
- Orthostatic intolerance
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation