{"id":{"repo_id":"uwo","oai_identifier":"oai:uwo.scholaris.ca:20.500.14721/37043"},"canonical_url":"https://search.dev.ndltd.org/etd/uwo/oai:uwo.scholaris.ca:20.500.14721/37043","repository":{"repo_id":"uwo","name":"Western University","base_url":"https://uwo.scholaris.ca/server/oai/request"},"display":{"title":"The Effects of Age and Long-Term Endurance Training on VO2 Kinetics","abstract":"The kinetics of the adjustment of pulmonary oxygen uptake (VO2) was examined during step transitions from 20 W to moderate-intensity cycling in young (Y), middle-aged (M), and older (O) endurance trained and untrained men. VO2p was measured breath-by-breath and changes in deoxygenated hemoglobin ([HHb]) were measured by near-infrared spectroscopy. VO2p and [HHb] were modeled with a monoexponential model. The kinetic time constant for VO2 (τVO2p) was not different across age-groups (P > 0.05) in the trained group (17 ± 8, 18 ± 5, and 20 ± 5 s, in Y, M, and O, respectively). For untrained, τVO2p was greater (P < 0.05) only in the O (26 ± 7, 24 ± 7, and 42 ± 11 s for Y, M, and O, respectively). The overall adjustment of [HHb] was faster than τVO2p in O untrained, resulting in an [HHb]/VO2p “overshoot” during the exercise transient; this may reflect a microvascular blood flow limitation. The present study suggests that long-term endurance training can abolish the age-related slowing of τVO2p via improved matching of local O2 delivery to muscle VO2.","abstract_html":"The kinetics of the adjustment of pulmonary oxygen uptake (VO2) was examined during step transitions from 20 W to moderate-intensity cycling in young (Y), middle-aged (M), and older (O) endurance trained and untrained men. VO2p was measured breath-by-breath and changes in deoxygenated hemoglobin ([HHb]) were measured by near-infrared spectroscopy. VO2p and [HHb] were modeled with a monoexponential model. The kinetic time constant for VO2 (τVO2p) was not different across age-groups (P &gt; 0.05) in the trained group (17 ± 8, 18 ± 5, and 20 ± 5 s, in Y, M, and O, respectively). For untrained, τVO2p was greater (P &lt; 0.05) only in the O (26 ± 7, 24 ± 7, and 42 ± 11 s for Y, M, and O, respectively). The overall adjustment of [HHb] was faster than τVO2p in O untrained, resulting in an [HHb]/VO2p “overshoot” during the exercise transient; this may reflect a microvascular blood flow limitation. The present study suggests that long-term endurance training can abolish the age-related slowing of τVO2p via improved matching of local O2 delivery to muscle VO2.","abstract_has_math":false,"creators":["Grey, Tyler M"],"institution":"The University of Western Ontario","degree_name":"M Sc","degree_level":null,"degree_discipline":"Kinesiology","degree_department":null,"school":null,"contributors":[],"advisors":["Donald H. 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In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."]},{"key":"dc:description.abstract","label":"Abstract","values":["The kinetics of the adjustment of pulmonary oxygen uptake (VO2) was examined during step transitions from 20 W to moderate-intensity cycling in young (Y), middle-aged (M), and older (O) endurance trained and untrained men. VO2p was measured breath-by-breath and changes in deoxygenated hemoglobin ([HHb]) were measured by near-infrared spectroscopy. VO2p and [HHb] were modeled with a monoexponential model. The kinetic time constant for VO2 (τVO2p) was not different across age-groups (P > 0.05) in the trained group (17 ± 8, 18 ± 5, and 20 ± 5 s, in Y, M, and O, respectively). For untrained, τVO2p was greater (P < 0.05) only in the O (26 ± 7, 24 ± 7, and 42 ± 11 s for Y, M, and O, respectively). The overall adjustment of [HHb] was faster than τVO2p in O untrained, resulting in an [HHb]/VO2p “overshoot” during the exercise transient; this may reflect a microvascular blood flow limitation. The present study suggests that long-term endurance training can abolish the age-related slowing of τVO2p via improved matching of local O2 delivery to muscle VO2."]},{"key":"dc:title","label":"Title","values":["The Effects of Age and Long-Term Endurance Training on VO2 Kinetics"]}]}],"canonical_facts":{"dc:contributor.advisor":["Donald H. Paterson"],"dc:creator":["Grey, Tyler M"],"dc:date.accessioned":["2025-07-10T21:29:00Z"],"dc:date.available":["2025-07-10T21:29:00Z"],"dc:date.issued":["2014-04-23"],"dc:description":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."],"dc:description.abstract":["The kinetics of the adjustment of pulmonary oxygen uptake (VO2) was examined during step transitions from 20 W to moderate-intensity cycling in young (Y), middle-aged (M), and older (O) endurance trained and untrained men. VO2p was measured breath-by-breath and changes in deoxygenated hemoglobin ([HHb]) were measured by near-infrared spectroscopy. VO2p and [HHb] were modeled with a monoexponential model. The kinetic time constant for VO2 (τVO2p) was not different across age-groups (P > 0.05) in the trained group (17 ± 8, 18 ± 5, and 20 ± 5 s, in Y, M, and O, respectively). For untrained, τVO2p was greater (P < 0.05) only in the O (26 ± 7, 24 ± 7, and 42 ± 11 s for Y, M, and O, respectively). The overall adjustment of [HHb] was faster than τVO2p in O untrained, resulting in an [HHb]/VO2p “overshoot” during the exercise transient; this may reflect a microvascular blood flow limitation. The present study suggests that long-term endurance training can abolish the age-related slowing of τVO2p via improved matching of local O2 delivery to muscle VO2."],"dc:identifier.uri":["https://hdl.handle.net/20.500.14721/37043"],"dc:language.iso":["en_ca"],"dc:publisher":["The University of Western Ontario"],"dc:subject":["O2 uptake kinetics","aging","trained","near-infrared spectroscopy"],"dc:title":["The Effects of Age and Long-Term Endurance Training on VO2 Kinetics"],"dc:type":["thesis"],"thesis:degree_discipline":["Kinesiology"],"thesis:degree_name":["M Sc"]},"updated_at":"2026-07-27T21:56:01Z"}