Prospective studies have shown that chronic low-grade inflammation may contribute to the pathogenesis of the most common chronic diseases and in particular CVD. Obesity has repeatedly been associated with moderately raised levels of inflammation, and this observation has led to the view that obesity is characterised by a state of chronic low-grade inflammation. There is now great interest in elucidating how physical activity and exercise modulate inflammation. This review summarises the current research addressing the influence of physical activity and exercise in mitigating the risks of obesity and diseases such as type-II diabetes and CVD, through its action on the low-grade inflammatory state. Most research on this topic hypothesised that the association between physical activity and inflammatory markers is independent of fatness, but very few studies have proven this. Given that physical activity and obesity are often inversely related, it is not clear as to whether the anti-inflammatory health benefits of a physically active lifestyle are due to exerciseper seor result from favourable changes in the body composition.