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Effects of High-Intensity Aerobic Interval Training on Cardiovascular Disease Risk and Health-related Quality of Life in Testicular Cancer Survivors: The HIITTS Trial
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- Author / Creator
- Adams, Scott C
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Background: Testicular cancer (TC) survivors (TCS) are an understudied, high-risk group susceptible to late-onset treatment-related cardiovascular disease (CVD), psychosocial, and health-related quality of life (HRQoL) deficits in the years following treatment. Importantly, despite having the second highest cure rate of all solid tumors, improvements in overall survival from testicular cancer are being off-set by treatment-related CVD. Aerobic exercise training prevents the development and mitigates the severity of cardiovascular and psychosocial deficits, similar to those experienced by TCS, in healthy and clinical populations including some cancer survivor groups. However, no studies to date have assessed the effects of aerobic exercise training on cardiovascular, psychosocial, and HRQoL deficits in TCS. High-intensity aerobic interval training (HIIT) is a modality of aerobic exercise training which involves alternating periods of vigorous- and light-intensity aerobic exercise; and, compared to moderate-intensity continuous aerobic exercise training (MCT), evidence suggests that HIIT may cause greater improvements in exercise capacity, cardiac and vascular health, metabolic and lipid-profile changes, antioxidant defenses, and possibly even HRQoL. Purpose: The purpose of my dissertation was to evaluate the effects of a 12-week aerobic HIIT program on traditional and novel CVD risk factors, surrogate markers of cardiovascular and overall mortality, psychosocial function, and HRQoL in a population-based sample of TCS. Methods: The High-Intensity Interval Training in Testicular cancer Survivors (HIITTS) trial was a randomized controlled trial. Recruited through the Alberta Cancer Registry and the surveillance clinic at the Cross Cancer Institute, 63 TCS were randomly allocated to either HIIT or a wait-list control usual care (UC) group. All HIIT and the UC participants were asked to maintain the low-to-moderate intensity physical activity they were performing at baseline throughout the duration of the 12-week intervention/observation period. Participants in the HIIT group were asked to attend thrice-weekly supervised exercise sessions for 12 weeks. The HIIT intervention consisted of four 4-minute work periods involving uphill walking/jogging on a treadmill between 75% and 95% of VO2peak which were separated by three 3-minute active recovery periods performed at a lower intensity, for a total of 35 minutes per session (including a 5-minute warm-up and 5-minute cool-down). Participants in the UC group were invited to participate in a 6-week condensed version of the HIIT protocol after the 3-month follow-up period. Assessments were made at baseline, immediately postintervention, and at 3-month follow-up [patient-reported outcomes (PROs) only]. Participants’ general and cardiovascular health were assessed using a maximal exercise protocol, non-invasive measures of vascular structure and function, resting and post exercise autonomic nervous system function, blood-based biomarkers, as well as self-report questionnaires (i.e., PROs) pertaining to physical activity, HRQoL, cancer-related fatigue (CRF), sleep quality, depression, anxiety, stress, and self-esteem. Results: Postintervention data were available in ≥97% of participants for our primary outcome (VO2peak) and 37 out of 45 (82%) secondary cardiovascular and PROs. HIIT participants completed 99% of all exercise sessions and achieved 98% of their target exercise intensity. Analysis of covariance (ANCOVA) revealed that, compared to UC, HIIT caused improvements in the primary outcome of VO2peak (3.7 mL O2/kg/min; 95% CI: 2.4 to 5.1; p<0.001) and numerous secondary outcomes including Framingham CVD Risk Score (FRS) (p=0.011), arterial-thickness (p<0.001), arterial-distensibility (p=0.049), arterial-stiffness (p<0.001), microvascular reactivity (p=0.039), resting heart rate (p=0.012), parasympathetic reactivity (p=0.033); post-exercise parasympathetic reactivation (p<0.001), inflammation (p=0.045), low-density lipoprotein (p=0.014), CRF (p=0.003), self-esteem (p=0.029), the mental component score (p=0.034), role-physical (p=0.048), general health (p=0.016), vitality (p=0.001), and social functioning (p=0.011). Moreover, the effects of HIIT on CRF (p=0.031) and vitality (p=0.015) persisted at 3-month follow-up. Exploratory analyses also provided preliminary evidence that changes in VO2peak may have partially mediated the postintervention improvements in the mental component score, vitality, and mental health; and the 3-month follow-up improvements in CRF and vitality. There were no HIIT-related adverse events. Conclusions: The HIITTS trial provides the first randomized evidence that 12 weeks of supervised HIIT causes significant and potentially clinically meaningful improvements in traditional and novel CVD risk factors, surrogate markers of cardiovascular and overall mortality, and patient-reported CRF, self-esteem, and HRQoL in TCS. If confirmed, the HIIT-related mitigation of treatment-related sequalae may lead to subsequent improvements in the quality and length of life in TCS. Further investigation of HIIT to reduce cardiovascular morbidity/mortality and improve both psychosocial function and HRQoL in TCS is warranted.
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- Graduation date
- Fall 2017
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.