Document Detail

Regulation of blood volume during training in post-menopausal women.
MedLine Citation:
PMID:  9475649     Owner:  NLM     Status:  MEDLINE    
In younger people the increase in aerobic capacity following training is related, in part, to blood volume (BV) expansion and the consequent improvements in maximal cardiac output. This training-induced hypervolemia is associated with a decrease in cardiopulmonary baroreflex (CPBR) control of peripheral vascular tone. PURPOSE: To test the hypothesis that improvement in peak oxygen consumption (VO2peak) during training in older women is associated with specific central adaptations, such as BV expansion and a reduction in CPBR control of vascular tone. METHODS: Seventeen healthy older women were randomized into training (N = 9, 71 +/- 2 yr) and control (N = 8, 73 +/- 3 yr) groups. The training group exercised three to four times per wk for 30 min at 60% peak heart rate for 12 wk and then 40-50 min at 75% peak heart rate for 12 wk. The control group participated in yoga exercises over the same time period. We measured resting BV (Evans blue dye), VO2peak, and the forearm vascular resistance response to unloading low pressure mechanoreceptors during low levels of lower body negative pressure (through -20 mm Hg) before and after aerobic training. The slope of the increase in forearm vascular resistance (response) per unit decrease in central venous pressure (stimulus) was used to assess CPBR responsiveness. RESULTS: Aerobic training increased VO2peak 14.2% from 24.2 mL x kg(-1) x min(-1) to 27.7 mL x kg(-1) x min(-1) (P < 0.05), a smaller improvement than typically seen in younger subjects. Blood volume (59.9 +/- 1.9 and 60.9 +/- 1.9 mL x kg[-1]) and CPBR function (-3.98 +/- 0.92 and -3.46 +/- 0.94 units x mm(-1) Hg) were similar before and after training. CONCLUSIONS: These data indicate that the inability to induce adaptations in CPBR function may limit BV expansion during training in older women. In addition, the absence of these specific adaptations may contribute to the relatively poor improvements in VO2peak in older women during short (10-12 wk) periods of training.
N S Stachenfeld; G W Mack; L DiPietro; T S Morocco; A C Jozsi; E R Nadel
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  30     ISSN:  0195-9131     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  1998 Jan 
Date Detail:
Created Date:  1998-03-27     Completed Date:  1998-03-27     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  92-8     Citation Subset:  IM; S    
Department of Epidemiology, Yale University School of Medicine, New Haven, CT 06519, USA.
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MeSH Terms
Adaptation, Physiological
Aging / physiology*
Baroreflex / physiology
Blood Pressure
Blood Volume / physiology*
Exercise / physiology*
Exercise Therapy
Oxygen Consumption / physiology*
Physical Endurance*
Postmenopause / physiology*
Vascular Resistance
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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