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Theses and Dissertations

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Browsing Theses and Dissertations by Author "Bachman, Nate P., author"

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    Cardiovascular disease risk in middle-aged ultra-endurance athletes
    (Colorado State University. Libraries, 2018) Bachman, Nate P., author; Dinenno, Frank, advisor; Richards, Jennifer, advisor; Chicco, Adam, committee member; Orton, Christopher, committee member
    Background: It is widely accepted that aerobic exercise has the ability to reduce cardiovascular disease (CVD) risk. However, recent studies suggest that volumes of exercise that greatly exceed physical activity guidelines may be damaging to the heart. Currently, it is unclear if individuals who train for ultra-endurance races are at an elevated risk of developing CVD compared to those that perform lower amounts of physical activity. Purpose: To use traditional and novel measures of CVD risk to determine if individuals that train for ultra-endurance races have a greater CVD risk compared to participants that engage in recreational physical activity. Methods: We studied two groups of healthy, middle-aged adults (40-65 y); Control (CON, n=18) subjects included individuals who were meeting current physical activity guidelines and the athletes (ATH, n=25) had been training for ultra-endurance events for 10 years. We used cardiac computed tomography (CT) to calculate coronary artery calcium scores (CACS) and magnetic resonance imaging (MRI) to assess for myocardial fibrosis (MF). Vascular function was evaluated using carotid-femoral pulse wave velocity (cfPWA) and flow-mediated dilation (FMD). 10-Year coronary heart disease (CHD) risk was also determined using a risk score calculator. Results: CACS > 0 was observed in 2 CON and 8 ATH; however, the presence of CAC was not significantly different between groups (P>0.05). Additionally, no participants in CON or ATH had MF. CON had higher cfPWV compared to ATH (6.9±0.2 vs 6.2±0.2 m/s, P<0.05), while no differences in FMD were observed (CON; 5.6±1.2 vs ATH; 3.6±0.8 %, P>0.05). Furthermore, there were no group differences in CHD risk (CON; 1.6±0.3 vs ATH; 2.4±0.6 %, P>0.05). Conclusion: ATH training for ultra-endurance races are not at a greater risk of experiencing a cardiac event than individuals that meeting current physical activity guidelines.
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    Novel modulators of blood pressure with age: a physiological and bioinformatics-based approach
    (Colorado State University. Libraries, 2021) Bachman, Nate P., author; Braun, Barry, advisor; LaRocca, Thomas J., advisor; Chicco, Adam J., committee member; Gentile, Christopher L., committee member
    Systolic blood pressure (SBP) increases with age and is a significant risk factor cardio- and cerebrovascular diseases. While the causes of high blood pressure (hypertension) have been extensively studied, the causes of the age-related rise in blood pressure independent of chronic disease remain unclear. Thus, the identification of novel mechanisms underlying age-related high blood pressure may lead to new strategies to reduce chronic disease risk in older adults. Therefore, the goal of this dissertation was to use both physiological and bioinformatics-based approaches to better elucidate contributors to elevated blood pressure in healthy older adults. The main findings are that 1) inhibition of Rho-kinase (an enzyme that participates in numerous cellular/regulatory pathways) lowers systemic blood pressure in healthy older adults concomitant with reduced vascular resistance but not improved endothelial function, 2) genes expression patterns in peripheral white blood cells differ in healthy older adults with elevated SBP compared to those with normal SBP and transcriptomic (RNA) changes relate to vascular and immune function, and 3) circulating chemokines and whole blood immune-related transcripts track with elevated SBP in healthy older adults. Taken together, this work shows that Rho-kinase, circulating RNA transcripts, and circulating chemokines may be novel therapeutic targets and/or biomarkers of elevated blood pressure in healthy older adults with untreated hypertension.