HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 98/3/845    most recent 00790.2004v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Bell, C. Articles by Seals, D. R. Search for Related Content PubMed PubMed Citation Articles by Bell, C. Articles by Seals, D. R.

Ascorbic acid does not affect the age-associated reduction in maximal cardiac output and oxygen consumption in healthy adults

Department of Integrative Physiology, University of Colorado, Boulder, Colorado

Submitted 27 July 2004 ; accepted in final form 21 October 2004

Maximal aerobic capacity (O_2max) decreases progressively with age, primarily because of a reduction in maximal cardiac output (_max). This age-associated decline in O_2max may be partially mediated by the development of oxidative stress that can suppress -adrenergic-receptor responsiveness and, consequently, reduce _max. To test this hypothesis, O_2max (indirect calorimetry) and _max (open-circuit acetylene breathing) were determined in 12 young (23 ± 1 yr, mean ± SE) and 10 older (61 ± 1 yr) adults following systemic infusion of either saline (control) and/or the powerful antioxidant ascorbic acid (acute: bolus 0.06; drip 0.02 g/kg fat-free mass) and following chronic 30-day oral administration of ascorbic acid (500 mg/day). Plasma ascorbic acid concentration was not different between young and older adults and was increased similarly, independent of age [change () acute = 1,055 ± 117%; chronic = 62 ± 19%]. Oxidized low-density lipoprotein concentration was greater (P < 0.001) in older (57 ± 5 U/l) compared with young (34 ± 3 U/l) adults and was reduced in both groups (P < 0.02) following acute ( = –6 ± 2%) but not chronic (P = 0.18) ascorbic acid administration. Control (baseline) O_2max and _max were positively related (r = 0.76, P < 0.001) and were lower (P < 0.05) in older (34 ± 2 ml·kg^–1·min^–1; 16.1 ± 1.1 l/min) compared with young (43 ± 3 ml·kg^–1·min^–1; 20.2 ± 0.9 l/min) adults. Following ascorbic acid administration, neither O_2max (young acute = 41 ± 2; young chronic = 42 ± 2; older acute = 34 ± 2; older chronic = 34 ± 2 ml·kg^–1·min^–1) nor _max (young acute = 20.1 ± 0.9; young chronic = 19.1 ± 0.8; older acute = 16.2 ± 1.1; older chronic = 16.6 ± 1.4 l/min) was changed. These data suggest that ascorbic acid administration does not affect the age-associated reduction in _max and O_2max.

maximum oxygen uptake; open-circuit acetylene breathing

This article has been cited by other articles:

				K. L. Jablonski, D. R. Seals, I. Eskurza, K. D. Monahan, and A. J. Donato High-dose ascorbic acid infusion abolishes chronic vasoconstriction and restores resting leg blood flow in healthy older men J Appl Physiol, November 1, 2007; 103(5): 1715 - 1721. [Abstract] [Full Text] [PDF]

				N. R. Stob, D. R. Seals, J. Jensen, M. A. van Baak, A. J. Steig, R. C. Lindstrom, B. T. Bikman, and C. Bell Autonomic Neuroscience: Increased thermogenic responsiveness to intravenous {beta}-adrenergic stimulation in habitually exercising humans is not related to skeletal muscle {beta}2-adrenergic receptor density Exp Physiol, September 1, 2007; 92(5): 823 - 830. [Abstract] [Full Text] [PDF]

				N. R. Stob, C. Bell, M. A. van Baak, and D. R. Seals Thermic effect of food and beta-adrenergic thermogenic responsiveness in habitually exercising and sedentary healthy adult humans J Appl Physiol, August 1, 2007; 103(2): 616 - 622. [Abstract] [Full Text] [PDF]

				K. L. Moreau, A. R. DePaulis, K. M. Gavin, and D. R. Seals Oxidative stress contributes to chronic leg vasoconstriction in estrogen-deficient postmenopausal women J Appl Physiol, March 1, 2007; 102(3): 890 - 895. [Abstract] [Full Text] [PDF]

				C. Bell, N. R. Stob, and D. R. Seals Thermogenic responsiveness to nonspecific beta-adrenergic stimulation is not related to genetic variation in codon 16 of the beta2-adrenergic receptor Am J Physiol Endocrinol Metab, April 1, 2006; 290(4): E703 - E707. [Abstract] [Full Text] [PDF]

				C. Bell, N. R. Stob, and D. R. Seals Thermogenic responsiveness to {beta}-adrenergic stimulation is augmented in exercising versus sedentary adults: role of oxidative stress J. Physiol., February 1, 2006; 570(3): 629 - 635. [Abstract] [Full Text] [PDF]

				K. L. Moreau, K. M. Gavin, A. E. Plum, and D. R. Seals Ascorbic Acid Selectively Improves Large Elastic Artery Compliance in Postmenopausal Women Hypertension, June 1, 2005; 45(6): 1107 - 1112. [Abstract] [Full Text] [PDF]