Effects of High Intensity Exercise on Oxidative Stress and Antioxidant Status in Untrained Humans: A Systematic Review

SIMPLE SUMMARY: This systematic review aims to investigate the influence of HIE on oxidative stress and antioxidant status in untrained humans. Following the PRISMA selection process, 21 studies were finally included. A rigorous methodological quality assessment (MQA) and levels of evidence was applied. There was strong evidence that acute oxidative stress occurs at the cessation of HIE when compared to resting states. The HIE-induced oxidative stress is transient and recoverable due to the stimulated endogenous antioxidant system. While the responses of antioxidant systems are lagging and lasting, multiple measurement times are suggested. Higher fitness levels are associated with less oxidative stress and regular physical exercise appears to improve antioxidant capacity and provide health benefits. ABSTRACT: Participation in exercise promotes health. High intensity exercise (HIE) has become increasingly popular among the general population, however, its effects on exercise-induced oxidative stress and antioxidant status in untrained humans is not clear. The aim of this systematic review was to investigate the influence of HIE on oxidative stress and antioxidant status in untrained humans. Web of Science, PubMed, MEDLINE, and Scopus were searched until March 2021. A methodological quality assessment valuation/estimation was additionally carried out in the final sample of studies. Following the PRISMA selection process, 21 studies were finally included. There was strong evidence that acute oxidative stress following the cessation of HIE exists when compared to resting states. The HIE-induced oxidative stress is transient and is most likely restored to normal levels within 24 h due to the stimulated endogenous antioxidant system whose response was lagging and lasting. Physically active humans had better antioxidant systems and suffered less oxidative stress after HIE. A physically active lifestyle was considered to enhance antioxidant capacity. For untrained humans, HIE with intensities above 70% VO(2)max are proposed for initial exercise levels based on the findings reported here.