Kinesiology
Permanent URI for this collectionhttps://hdl.handle.net/11274/15371
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Browsing Kinesiology by Author "Armstrong, Lawrence E."
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Item The acute testosterone, growth hormone, cortisol and interleukin-6 response to 164-km road cycling in a hot environment(Taylor & Francis, 2015) Duplanty, Anthony A.; Vingren, Jakob L.; Budnar, Ronald G.; McKenzie, Amy L.; Luk, Hui-Ying; Levitt, Danielle E.; Armstrong, Lawrence E.This study investigated the acute endocrine responses to a 164-km road cycling event in a hot environment. Thirty-four male experienced cyclists (49.1 ± 8.3 years, 86.8 ± 12.5 kg, 178.1 ± 5.1 cm) participating in a 164-km road cycling event were recruited. Blood samples were collected within 0.3–2.0 h before the start (PRE: ~0500–0700 h) and immediately following the ride (POST). Samples were analysed for testosterone, growth hormone (GH), cortisol and interleukin-6 (IL-6). The temperature and humidity during the event were 35.3 ± 4.9°C and 47.2 ± 14.0%, respectively. Based on the finishing time, results for the fastest (FAST, 305 ± 10 min) and the slowest (SLOW, 467 ± 31 min) quartiles were compared. At POST, testosterone concentration was significantly (P < 0.05) lower (PRE, 20.8 ± 8.6; POST, 18.2 ± 6.7 nmol · L−1), while GH (PRE, 0.3 ± 0.1; POST, 2.3 ± 0.3 µg · L−1), cortisol (PRE, 661 ± 165; POST, 1073 ± 260 nmol · L−1) and IL-6 (PRE, 4.0 ± 3.4; POST, 22.4 ± 15.2 pg · mL−1) concentrations were significantly higher than those at PRE. At POST, GH and cortisol were significantly higher for the FAST group than for the SLOW group (GH, 3.6 ± 2.0 and 1.0 ± 0.8 µg · L−1; cortisol, 1187 ± 209 and 867 ± 215 nmol · L−1). Participation in an ultra-endurance road cycling event in a hot environment induced significant acute changes in concentrations of circulating hormones, with a greater augmentation of GH and cortisol in those completing the ride fastest.Item Leukocyte subset changes in response to a 164-km road cycle ride in a hot environment(Western Kentucky University, 2016) Duplanty, Anthony A.; Luk, Hui Ying; McKenzie, Amy L.; Budnar, Ronald G.; Levitt, Danielle; Fernandez, Alex; Lee, Elaine C.; Armstrong, Lawrence E.; Vingren, Jakob L.The purpose of this observational study was to determine the circulating leukocyte subset response to completing the 2013 Hotter’N Hell Hundred recreational 164-km road cycle event in a hot and humid environmental condition. Twenty-eight men and four women were included in this study. Whole blood samples were obtained 1-2 hours before (PRE) and immediately after (POST) the event. Electronic sizing/sorting and cytometry were used to determine complete blood counts (CBC) including neutrophil, monocyte, and lymphocyte subsets. The concentration of circulating total leukocytes (103·µL-1) increased 134% from PRE to POST with the greatest increase in neutrophils (319%, p<0.0001). Circulating monocytes (including macrophages) increased 24% (p=0.004) and circulating lymphocytes including B and T cells increased 53% (p<0.0001). No association was observed between rolling time or relative intensity and leukocyte subset. Completing the Hotter n’ Hell Hundred (HHH), a 100 mile recreational cycling race in extreme (hot and humid) environmental conditions, induces a substantial increase in total leukocytes in circulation. The contribution of increases in specific immune cell subsets is not equal, with neutrophils increasing to greater than 4-fold starting values from PRE to POST race. It is likely that exercise in stressful environmental conditions affects the complement of circulating immune cells, although activational state and characterization of specific leukocyte subsets remains unclear. The observed increase in circulating cell sub-populations suggests that the circulating immune surveillance system may be acutely affected by exercise in hot and humid conditions.