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Afferent baroreflex dysfunction and age-related orthostatic hypotension
A L Tonkin1, L M Wing, M J Morris
1Department of Clinical Pharmacology, Flinders Medical Centre, Bedford Park, South Australia.
Clinical Science (London, England : 1979)
|October 1, 1991
Summary
Elderly individuals with orthostatic hypotension exhibit baroreflex dysfunction, indicated by abnormal blood pressure responses to head-up tilt but normal reactions to cold stress and exercise.
Area of Science:
- Cardiovascular Physiology
- Gerontology
- Neuroscience
Background:
- Orthostatic hypotension (OH) is common in the elderly.
- Baroreflex dysfunction may contribute to age-related OH.
- Understanding the underlying mechanisms is crucial for effective management.
Purpose of the Study:
- To investigate baroreflex function in elderly subjects with OH.
- To differentiate between baroreceptor-mediated and non-baroreceptor-mediated responses.
- To explore potential cardiovascular and neurohumoral alterations.
Main Methods:
- Cardiovascular and neurohumoral responses were measured.
- Stimuli included head-up tilt (baroreceptor activation), cold stress, and isometric exercise (non-baroreceptor activation).
- Aorto-iliac pulse wave velocity was assessed.
Main Results:
- Elderly subjects with OH showed a marked blood pressure drop during head-up tilt, unlike controls.
- Both groups exhibited similar responses to cold stress and isometric exercise.
- Subjects with OH had increased aorto-iliac pulse wave velocity, suggesting arterial stiffness.
Conclusions:
- Elderly individuals with OH demonstrate impaired baroreflex function.
- The findings distinguish OH from autonomic neuropathy in the elderly.
- Arterial stiffness may play a role in age-related orthostatic hypotension.