AUTHOR=Watson Alastair , Wilkinson Tom M. A. , Freeman Anna 

TITLE=Evidence Around the Impact of Pulmonary Rehabilitation and Exercise on Redox Status in COPD: A Systematic Review

JOURNAL=Frontiers in Sports and Active Living

VOLUME=Volume 3 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2021.782590

DOI=10.3389/fspor.2021.782590

ISSN=2624-9367

ABSTRACT=Introduction: Oxidative stress is increasingly recognized as a significant factor in COPD pathogenesis. Pulmonary rehabilitation, a major component of which is prescribed exercise, is essential in COPD care. Regular exercise has been proposed to increase antioxidant defenses and overall enhance the body’s ability to counteract oxidative stress. However, the mechanisms through which it improves COPD outcomes remain unclear. 
Objectives: We aimed to appraise the current evidence around the impact of pulmonary rehabilitation on redox status, compared with other exercise interventions, to gain an understanding of optimal exercise interventions to modify this pathophysiological mechanism.
Methods: We performed a systematic review through searching CENTRAL; MEDLINE; PubMed; Scopus and Web of science. Results were independently reviewed, and relevant studies were selected by two independent assessors. Studies were assessed by two independent people using a modified ROB2 tool, discrepancies were resolved through discussion.
Results: We identified 1,710 records, 1,117 after duplicate removal. Six studies were included in the final analysis. The evidence available was low quality, four studies had high and two have unclear risk of bias. Studies were small (15-56 participants), only two included details of randomization and patient cohorts were of varying ages and poorly described. Differences in smoking status and previous exercise levels, known to impact redox status, were not well documented. Studies were not standardized and used different exercise doses and measured different outcomes. One study reported lower malondialdehyde levels, a marker of lipid peroxidation, after pulmonary rehabilitation, compared with control. However, one study saw no difference following whole body vibration training and another showed higher malondialdehyde levels following supervised modified arm swing exercise compared with control.
Conclusions: Understanding the impact of exercise on oxidative stress in COPD could lead to tailored exercise programmes and modification of pathological mechanisms. However, we identify a lack of high-quality evidence to determine this. Larger, standardized, high quality randomized controlled trials (RCTs) are essential which use carefully clinically characterized and controlled cohorts to determine the relative impact of different exercise interventions on redox status to guide COPD management. We describe an idealized RCT design which could be used to try and meet this need.