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Cardiovascular responses to postural changes: differences with age for women and men
M A Frey1, C M Tomaselli, W G Hoffler
1Biomedical Operations and Research Office, Kennedy Space Center, Florida.
Journal of Clinical Pharmacology
|May 1, 1994
Summary
Cardiovascular responses to standing change with age and sex. Older individuals and women show distinct blood pressure and resistance changes, influenced by baroreceptor function and blood volume.
Area of Science:
- Cardiovascular Physiology
- Gerontology
- Exercise Physiology
Background:
- Cardiovascular responses to postural changes are not well understood in women.
- Aging significantly impacts physiological responses, including cardiovascular adjustments.
Purpose of the Study:
- To investigate the influence of age and sex on cardiovascular responses to postural changes.
- To analyze changes in blood pressure, cardiac output, heart rate, and total peripheral resistance (TPR) during postural transitions.
Main Methods:
- Measurements of cardiovascular variables were taken in supine, seated, and standing positions.
- 22 men and 25 women aged 21-59 years participated in the study.
Main Results:
- Postural changes elicited significant increases in diastolic and mean arterial pressures, heart rate, and TPR, with decreases in cardiac output and stroke volume.
- Age and sex influenced these responses: younger individuals had greater heart rate increases, while older individuals showed larger TPR and thoracic impedance increases.
- Women exhibited less stroke volume decrease and greater TPR and thoracic impedance increases compared to men, with older women showing a pronounced TPR increase.
Conclusions:
- Cardiovascular responses to standing differ between sexes and age groups.
- Sex differences may relate to thoracic blood volume changes, while age differences are linked to baroreceptor system responsiveness.