Anti-Inflammatory and Antioxidant Effects of HIIT in Individuals with Long COVID: Insights into the Potential Role of .

Long COVID is characterized by persistent symptoms associated with chronic inflammation and oxidative stress. While high-intensity interval training (HIIT) and supplementation with antioxidants such as have demonstrated individual therapeutic benefits, their combined effects remain unclear. This study aimed primarily to evaluate the effects of an 8-week HIIT program on markers of inflammation, oxidative stress, and exercise-related symptoms in individuals with long COVID, and secondarily to explore whether supplementation provided additional benefits. A total of 104 participants (aged 18-59 years) were randomized into three groups-control (placebo), HIIT (cycling for 28 min/day, 3 days/week), and combined (HIIT + , 1000 mg/day)-for 8 weeks. The biomarkers assessed included interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), protein carbonyls, and superoxide dismutase (SOD) activity. Following the intervention, significant reductions in IFN-γ, TNF-α, MDA, protein carbonyls, and rating of perceived exertion were observed in both the HIIT and combined groups ( < 0.05), with no significant differences between the two. SOD activity significantly increased in all groups, including the control group ( < 0.05), with no between-group differences. An 8-week HIIT program appears to be effective in reducing inflammation, oxidative stress, and dyspnea in individuals with long COVID. supplementation did not provide any additional statistically significant benefit but was safe and well tolerated.