The effect of exercise on inflammatory biomarkers

Introduction Many non-communicable diseases (NCDs) including dementia and some cancers have a component of underlying inflammation within their pathophysiology. Exercise has been shown to reduce morbidity and mortality from NCDs and has been linked with decreased levels of pro-inflammatory cytokines in the plasma of regularly exercising individuals. This project seeks to assess the effect of acute and chronic exercise, including high intensity interval training on inflammatory markers within the cerebrospinal fluid (CSF) and plasma. Methods A systematic review and meta-analysis were performed to identify the effects of long term (>6 weeks) exercise on inflammatory markers within the cerebrospinal fluid and plasma. Healthy male volunteers were recruited for a study investigating the effect of an acute high-intensity interval training (HIT) protocol on inflammatory markers (IL-6, IL-10, TNF and CRP) in CSF. Plasma from volunteers with and without cancer in previous HIT studies was analysed to assess levels of inflammatory biomarkers (IL-6, IL-10, TNF and CRP) pre- and post- exercise interventions. Results A systematic review revealed few statistically significant results showing either increases or decreases in inflammatory markers following a variety of exercise protocols. It was not possible to recruit sufficient volunteers to analyse CSF following exercise and the study was not completed during the time frame of this thesis. The analysis of plasma showed a significant decrease in IL-6 in an elderly population following 4 weeks of HIT, there was also a significant increase seen in a group performing HIT at home. Conclusions The data obtained did not support consistent effects of exercise on inflammatory markers in healthy individuals, or in those with cancer. There was some evidence to show that HIT may reduce levels of circulating IL-6 in elderly (>70 years) populations. There may be many cofounders which influence the levels of inflammatory markers within individuals, making a relationship with exercise more difficult to ascertain.