Effect of exercise intensity on redox biomarkers in healthy adults: A systematic review and meta-analysis of randomized clinical trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 40834031 · doi:10.1371/journal.pone.0330185
What was done
A systematic review and meta-analysis of randomized controlled trials following PRISMA guidelines. Authors searched nine databases (Scopus, Web of Science, PubMed, Springer, Science Direct, Cochrane Library, Dialnet, Redalyc, Lilacs) for RCTs evaluating the effects of chronic vigorous versus non-vigorous exercise interventions on redox status biomarkers in healthy adults. Study quality and risk of bias were evaluated using the PEDro scale and Cochrane RoB 2 tool. Seven RCTs evaluating nine training protocols were included.
What was found
Pooled analysis of 7 RCTs (n = 267) showed significant overall increases in antioxidant capacity (Z = 4.56, p < 0.00001, I² = 0%) and superoxide dismutase (Z = 1.94, p = 0.05, I² = 52%), and a significant decrease in pro-oxidants (Z = 5.91, p < 0.0001, I² = 0%). Glutathione peroxidase did not differ significantly (Z = 0.50, p = 0.62, I² = 81%). Vigorous exercise alone significantly increased antioxidants (Z = 2.44, p = 0.01, I² = 67%) and reduced oxidants (Z = 5.44, p < 0.00001, I² = 0%), whereas non-vigorous exercise showed no statistically significant differences in redox markers. Specific effect sizes and point estimates were not provided in the abstract.
Why it matters
This review suggests that improvements in endogenous antioxidant defenses and reductions in oxidative stress biomarkers in healthy adults are intensity-dependent, favoring vigorous physical activity over lower-intensity regimens.
Limits
The total sample size is small across few studies (7 RCTs, 267 total participants). Substantial heterogeneity was observed for glutathione peroxidase (I² = 81%) and antioxidant response to vigorous exercise (I² = 67%). The abstract does not report specific effect sizes, intervention durations, participant demographics, or exercise modalities.
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