Abstract：
PURPOSE:To test the hypothesis that leg blood flow and leg O2 extraction during peak exercise are reduced with age in healthy normally active women. METHODS:Thirteen younger (20-27 yr) and 12 older (60-71 yr) nonendurance trained women performed graded upright leg cycling to maximum exertion (VO2peak), while leg blood flow (femoral vein thermodilution), cardiac output (acetylene rebreathing), mean arterial pressure (MAP, radial artery), and blood O2 contents were measured. RESULTS:Peak leg VO2 was 32% lower in the older versus younger women (0.81 +/- 0.06 vs 1.18 +/- 0.10 L x min(-1)) and was correlated with peak systemic VO2 (1.33 +/- 0.1 vs 1.78 +/- 0.1 L x min(-1)) in both groups. Peak leg blood flow and estimated leg vascular conductance were 29% and 38% lower, respectively, in the older women (both P < 0.001). Peak leg blood flow and peak estimated cardiac output were correlated in the older (r2 = 0.51, P = 0.02), but not younger (r2 = 0.10, P = 0.35), group. Estimates of peak systemic and leg arterial-venous O2 difference did not differ between groups (both P > 0.28). CONCLUSIONS:Reduced leg blood flow is a major contributor to the reduced peak systemic VO2 observed in older nonendurance trained women. Diminished leg blood flow during peak exercise in older women, in turn, is due to both central (reduced cardiac output) and peripheral (reduced leg vascular conductance) limitations.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Proctor DN,Koch DW,Newcomer SC,Le KU,Smithmyer SL,Leuenberger UAdoi
10.1249/01.mss.0000121951.10417.b5subject
Has Abstractpub_date
2004-04-01 00:00:00pages
623-31issue
4eissn
0195-9131issn
1530-0315pii
00005768-200404000-00011journal_volume
36pub_type
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journal_title：Medicine and science in sports and exercise
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