Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and\/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether an acute oral dose can similarly improve FBF or enhance the ability to blunt sympathetic vasoconstriction during exercise. We hypothesized that 1) acute oral AA would improve FBF (Doppler ultrasound) and oxygen consumption (V\u0307o2) via local vasodilation during graded rhythmic handgrip exercise in older adults (protocol 1), and 2) AA ingestion would not enhance sympatholysis in older adults during handgrip exercise (protocol 2). In protocol 1 (n = 8; 65 \u00b1 3 yr), AA did not influence FBF or V\u0307o2 during rest or 5% maximal voluntary contraction (MVC) exercise, but increased FBF (199 \u00b1 13 vs. 248 \u00b1 16 ml\/min and 343 \u00b1 24 vs. 403 \u00b1 33 ml\/min; P < 0.05) and V\u0307o2 (26 \u00b1 2 vs. 34 \u00b1 3 ml\/min and 43 \u00b1 4 vs. 50 \u00b1 5 ml\/min; P < 0.05) at both 15 and 25% MVC, respectively. The increased FBF was due to elevations in forearm vascular conductance (FVC). In protocol 2 (n = 10; 63 \u00b1 2 yr), following AA, FBF was similarly elevated during 15% MVC (\u223c 20%); however, vasoconstriction to reflex increases in sympathetic activity during -40 mmHg lower-body negative pressure at rest (\u0394FVC: -16 \u00b1 3 vs. -16 \u00b1 2%) or during 15% MVC (\u0394FVC: -12 \u00b1 2 vs. -11 \u00b1 4%) was unchanged. Our collective results indicate that acute oral ingestion of AA improves muscle blood flow and V\u0307o2 during exercise in older adults via local vasodilation.\n\n\n
Jennifer C Richards,\u00a0Anne R Crecelius,\u00a0Dennis G Larson,\u00a0Frank A Dinenno<\/p>\n
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Summary Human aging is associated with reduced skeletal muscle perfusion during exercise, which may be a result of impaired endothelium-dependent dilation and\/or attenuated ability to blunt sympathetically mediated vasoconstriction. Intra-arterial infusion of ascorbic acid (AA) increases nitric oxide-mediated vasodilation and forearm blood flow (FBF) during handgrip exercise in older adults, yet it remains unknown whether…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[69],"tags":[545],"_links":{"self":[{"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/posts\/7228"}],"collection":[{"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/comments?post=7228"}],"version-history":[{"count":0,"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/posts\/7228\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/media?parent=7228"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/categories?post=7228"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.healthlibrary.info\/wp-json\/wp\/v2\/tags?post=7228"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}