Browsing by Subject "Aerobic exercise"

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    Effect of aerobic exercise on cognition and brain activity following traumatic brain injury
    (2014-02) Lojovich, Jeanne Marie
    Following the Introduction, this thesis is organized into three parts. Part one (Chapter II), is an extensive literature review related to the scientific promise and potential physiological mechanisms underlying aerobic exercise as a potential intervention to improve cognition following TBI. This literature review was initially published in the Journal of Head Trauma Rehabilitation 25(3):184-192, May/June 2010 by the author of this thesis.55 Parts two and three are two separate research reports written as Chapters III and IV. Each report was formatted for journal submission. The first study (Chapter III) reports cognitive changes in working memory, executive function, and the subject's (N=7) perceived function utilizing behavioral measures following participation in a 12-week aerobic exercise program. The second study (Chapter IV) reports findings of the cortical changes in TBI subjects (N=7) following participation in a 12-week aerobic exercise program. Functional magnetic imaging (fMRI) data was gathered on the subjects during a working memory task prior to and following exercise program participation. Regions of interest in the cortex included the dorsolateral prefrontal cortex, anterior and posterior cingulate cortices, and the precuneus.
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    The effects of aerobic exercise on premenopausal levels of endogenous sex hormones and urinary estrogen metabolism
    (2015-03) Smith, Alma Judith
    The purpose of this doctoral project was to investigate the effects of aerobic exercise on breast cancer risk biomarkers such as endogenous sex hormone levels and urinary estrogen metabolites in premenopausal women. In this study, 391 healthy, sedentary, young eumenorrheic women were randomized to either an exercise intervention of 30 minutes of moderate-to-vigorous aerobic exercise five times a week for approximately 16 weeks (n = 212) or a usual-lifestyle sedentary control group (n = 179). Outcome measures were taken at baseline and follow-up.The study described in Chapter 2 evaluated changes in serum levels of estradiol, estrone sulfate, testosterone, progesterone, and sex hormone-binding globulin (SHBG) via radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) methods. As expected, the intervention resulted in significant increases in aerobic fitness, lean body mass, and decreases in percent body fat in women in the exercise group. No significant changes in body weight were observed between or within groups. The major finding of this study was a significant decrease in progesterone in the exercise group, albeit this change was similar to that of the control group. The lack of significant changes in sex hormone or SHBG levels due to the intervention (without a concomitant weight change) between or within groups suggest this may not be a plausible mechanism by which physical activity decreases breast cancer risk in premenopausal women.The second study described in Chapter 3 measured changes in urinary levels of estrogens (estrone [E1], and estradiol [E2]), and ten estrogen metabolites via liquid chromatography/tandem mass spectrometry (LC-MS/MS). In addition, the ratios of 2-hydroxyestrone to 16α-hydroxyestrone (2-OHE1/16α-OHE1) and 2-hydroxyestrone to 4-hydroxyestrone (2-OHE1/4-OHE1) were calculated. Although no significant changes in urinary estrogens or their metabolites were found between groups, the 2-OHE1/16α-OHE1 ratio in exercisers increased significantly (P = 0.043) compared to the control group (P = 0.045), even after adjustment for baseline values.Collectively, the results of this doctoral project suggest the positive effects aerobic exercise allegedly has on premenopausal breast cancer risk may be mediated through hormonal mechanisms that involve changes in estrogen metabolism but not necessarily changes in endogenous sex hormone levels.