Year of Award

2022

Document Type

Dissertation

Degree Type

Doctor of Philosophy (PhD)

Degree Name

Integrative Physiology and Rehabilitation Sciences

Department or School/College

Integrative Physiology and Athletic Training

Committee Chair

John C. Quindry

Commitee Members

Charles L. Dumke, Valerie Moody, Brent C. Ruby, Tony Ward

Keywords

cardiac rehabilitation, exercise, home-based cardiac rehabilitation

Abstract

This dissertation addresses the following questions: 1) the impact of three environmental conditions (altitude, heat, and woodsmoke exposure) on the blood oxidative stress response to exercise; 2) the effect of exercise-based cardiac rehabilitation programs (home-based, HBCR; traditional, TCR) on health outcomes in those who have experienced a cardiovascular event and/or severe diagnosis resulting in referral to cardiac rehabilitation. Study 1: Examine effects of lab-simulated hypobaric and hypoxic conditions on oxidative stress during a 4-hour recovery period after 1-hour of cycling (70% watts max). Exercise increased markers of antioxidant status (TEAC, FRAP) and lipid damage (8-ISO) (p<0.05). No effects of hypobaria and hypoxia were observed. Study 2: Compare the blood oxidative stress response to an exercise tolerance trial (1-hour, 50% Wpeak) in hot (33ºC) and room temperature (20ºC) environments following acclimation training (15 sessions). Exercise increased markers of antioxidant status (TEAC, FRAP) and lipid damage (LOOH) (p<0.001). No effect of environmental temperature was observed. Study 3: Investigate the effect of woodsmoke exposure (200 μg·m-3) on variables of cardiovascular function (heart rate variability, HRV; pulse wave velocity PWV) and oxidative stress with 45-min of moderate intensity exercise (70% VO2max). Woodsmoke exposure did not reduce HRV, increase PWV, or increase oxidative stress (p>0.05). Study 4: The final study was conducted to compare the effectiveness of TCR and HBCR as determined by improvements in exercise capacity (peak metabolic equivalents, peak METs), resting heart rate (RHR), resting systolic (SBP) and diastolic (DBP) blood pressure, body mass index (BMI), and depression outcomes (PHQ-9). Peak METs and PHQ-9 scores improved in both TCR and HBCR (p<0.001); however, greater improvements in peak METs occurred with TCR (p=0.034). No association between intervention type and program completion was observed (p=0.172). The results of these investigations indicate 1) lab-simulated hypobaric and/or hypoxic conditions do not impact the oxidative stress response to exercise; 2) 15 sessions of acclimation training in a hot environment do not alter the oxidative stress response to an exercise tolerance trial; 3) Woodsmoke exposure (200 μg·m-3) with moderate intensity exercise did not negatively impact HRV, PWV or blood oxidative stress; 4) HBCR and TCR improve peak METs and PHQ-9 outcomes.

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