The influence of structured physical activity on vaccination response from adults to older individuals: a systematic review on the Immunoinflammatory crosstalk of COVID-19.

BACKGROUND: Amidst the ongoing COVID-19 pandemic, understanding factors that influence vaccine efficacy is crucial, particularly in older adults. Regular physical exercise and/or structured physical activity (SPA) has emerged as a potential modulator of immune responses, enhancing vaccine effectiveness. This systematic review aims to consolidate current evidence on the impact of SPA/exercise on both immune and inflammatory responses to COVID-19 vaccination in adults and older individuals. METHODS: Most relevant studies were extracted from indexed databases using health subject terms in English, Portuguese, and Spanish. Studies that examined the impact of regular exercise or SPA on inflammatory and/or immunological responses in relation to COVID-19 immunization were selected. In particular, all chosen studies included individuals who received vaccinations either prior to or following the exercise regimen or SPA, and the main goal was to evaluate these effects on immunological and/or inflammatory reactions induced by vaccination. RESULTS: Among the 7 studies included (n = 1149), the effects of regular exercise or PA on vaccine-induced immune responses while concurrently assessing inflammatory markers were examined. The findings suggest that moderate to high-intensity structured physical activity (50-70% of maximum heart rate for aerobic exercise and 60-80% of 1RM for resistance training), performed 3-5 times per week, was able to enhance immune responses to COVID-19 vaccination, particularly by mitigating chronic low-grade inflammation. Acute exercise can transiently boost immunity, whilst engagement in moderate SPA over a period of six months may contribute to sustained improvements in immune function, especially in older adults. However, these findings should be interpreted with caution due to variability in study design, sample characteristics, and potential confounding factors. CONCLUSION: Regular exercise and SPA play a significant role in improving immune/inflammatory responses to COVID-19 vaccination. Older adults, in particular, may benefit from regular SPA and exercise as a strategy to counteract immunosenescence and optimize vaccine efficacy. However, further research is needed to better refine exercise protocols and determine long-term benefits in different populations.