Browsing by Author "Miller M"

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    Chronic carbohydrate restriction improves endurance capacity and body composition in men and women
    (Cycling Research Center, 2022-06-06) O'Connor W; O'Connor E; Barnes M; Miller M; Gardener H; Stannard S; Zabala M
    This study was designed to test whether adaptation to a CHO-restricted diet affects physical capacity during prolonged exercise. It is hypothesised that chronically reducing an individual’s dietary carbohydrate intake during training will increase their maximal rate of fatty acid oxidation during subsequent exercise compared to a chronic high carbohydrate diet. Thirteen highly trained endurance athletes (eight males, VO2max 66.0 ± 9.5 ml/kg/min, five females VO2max 50.6 ± 8.4 ml/kg/min) consumed a high (>5 g CHO/kg/day) or low (<2 g CHO/kg/day) carbohydrate training diet for four weeks in a randomized cross-over design. Performance was measured after a 24 h high carbohydrate “loading” regime, through a self-paced time trial to complete a fixed workload equivalent to five hours at a workload calculated to elicit 55% VO2max. Although time to completion was not significantly different between diets, the average absolute (watts) and relative (W/kg) power outputs were significantly better on the carbohydrate restricted diet (p = 0.03 and 0.02 respectively). Both sexes responded similarly in terms of performance whilst only women significantly improved body composition when carbohydrate was restricted (p = 0.02). Results from this study highlight that when carbohydrate is restricted during training, trained endurance athletes show improved ultra-endurance performance relative to their body mass.
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    Use of butorphanol and diprenorphine to counter respiratory impairment in the immobilised white rhinoceros (Ceratotherium simum)
    (African Online Scientific Information Systems (Pty) Ltd t/a AOSIS, 2018-10-18) Meyer LCR; Fuller A; Hofmeyr M; Buss P; Miller M; Haw A
    Opioid-induced immobilisation results in severe respiratory impairment in the white rhinoceros. It has therefore been attempted in the field to reverse this impairment with the use of opioid agonist-antagonists, such as nalorphine, nalbuphine, butorphanol and diprenorphine; however, the efficacy of some of these treatments has yet to be determined. The efficacy of butorphanol, either alone or in combination with diprenorphine both with and without oxygen insufflation, in alleviating opioid-induced respiratory impairment was evaluated. The study was performed in two parts: a boma trial and a field trial. Rhinoceroses were immobilised specifically for the study, according to a strict protocol to minimise confounding variables. A two-way analysis of variance was used to compare the physiological responses of the rhinoceroses to the different treatments and their effects over time. The intravenous administration of butorphanol (at 3.3 mg per mg etorphine) plus diprenorphine (at 0.4 mg per mg etorphine) did not offer any advantage over butorphanol (at 15 mg per mg etorphine) alone with regard to improving PaO2, PaCO2 and respiratory rates in etorphine-immobilised white rhinoceroses. Both butorphanol + diprenorphine + oxygen and butorphanol + oxygen, at the doses used, significantly improved the etorphine-induced hypoxaemia in both boma- and field-immobilised white rhinoceroses. Clinically acceptable oxygenation in field-immobilised white rhinoceroses can be achieved by using either treatment regimen, provided that it is combined with oxygen insufflation.