Impact of a 6-month aerobic exercise intervention on oxidative stress in sedentary older adults
Date
2018-12-17
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Background: Reactive oxygen species (ROS) play integral roles in cell signalling and systemic processes and are tightly controlled through workings of antioxidants. An imbalance in this relationship can lead to oxidative stress. Completion of regular exercise can mitigate oxidative stress, strengthen antioxidant capacity and improve oxidative stress- associated conditions, such as metabolic syndrome (MetS) and decreased cerebrovascular function. However, there is limited knowledge as to how the aging population with and without MetS compare in terms of changes in markers of oxidative stress and antioxidant profiles with an aerobic exercise intervention, and the effect these changes in have on
cerebrovascular function. Objective: We aimed to assess the effects of a 6-month aerobic exercise intervention on markers of oxidative stress and antioxidant capacity in older, sedentary yet healthy adults, and to determine how MetS status affected these exercise-induced changes. Further, as an exploratory measure, we aimed to assess the association between changes in markers of oxidative stress and antioxidant capacity and measures of cerebrovascular function. Design: Blood samples from 206 participants (mean age=66.8 ± SE=6.4 years, 104 females) pre-, midway, and post-intervention were assessed for markers of oxidative stress (advanced oxidation protein products [AOPP; malondialdehyde [MDA]; 3-nitrotyrosine [3-NT]) and antioxidant capacity (superoxide dismutase [SOD]; uric acid [UA]; ferric- reducing ability of ṗ lasma [FRAP]; nitric oxide metabolites [NOx]; catalase). Maximal aerobic capacity (VO2max), anthropometric and demographic information was also collected. Repeated measures linear mixed models adjusted for covariates were used to evaluate changes in markers of oxidative stress and antioxidant capacity across the exercise intervention. Factors represented by changes in markers of oxidative stress and antioxidant status were used in a linear regression analysis to assess the potential association between oxidative stress and cerebrovascular function. Results: There was a significant effect of the exercise intervention on decreasing levels of AOPP (p=0.004) however, neither MetS status (p=0.214) nor sex (p=0.437) modified the effect. Individuals with MetS had significantly higher levels of AOPP (p<0.001), MDA (p<0.001), FRAP (p=0.03) and UA (p=0.003) compared to those without. Men possessed significantly higher levels of AOPP (p=0.001), FRAP (p<0.001), catalase (p=0.013) and UA (p<0.001) compared to women. Interestingly, the effect of MetS status on FRAP and 3-NT was highly dependent on sex. Further, exercise-induced changes in measures of oxidative stress and antioxidant status were significantly associated with post-intervention measures of cerebrovascular function at rest and submaximal exercise. Conclusion: These results indicate that MetS may blunt exercise-induced improvements in oxidative stress and that changes in markers of oxidative stress and antioxidant status may impact exercise-induced cerebrovascular improvements in older, healthy adults.
Description
Keywords
oxidative stress, aging, aerobic exercise, metabolic syndrome
Citation
Rytz, C. L. (2018). Impact of a 6-month aerobic exercise intervention on oxidative stress in sedentary older adults (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.