Chronic Systemic Inflammation, Body Composition and Physical Activity Behaviours in Older Adults

Ageing is associated with a gradual physical decline accompanied by changes in body composition. The occurrence of a low-grade yet chronic state of systemic inflammation has gained interest for its potential consequences in the ageing process. Importantly, a physically active lifestyle may promote the maintenance of muscle mass, reduction in adipose tissue, and alleviate progression of a chronic pro-inflammatory state. The overall aim of this thesis was to explore relationships between biomarkers of systemic inflammation, body composition, and physical activity behaviours in community-dwelling older adults aged 65 to 70 years. A main finding of the thesis is the existence of associations between body composition and systemic inflammation in older adults, where excess adipose tissue is adversely associated with levels of inflammatory biomarkers in older women. Inverse associations were also observed between muscle mass and levels of pro-inflammatory biomarkers in older women. This thesis also highlights sex-specific associations between systemic inflammation and physical activity behaviours. Longer time spent sedentary was also associated with higher levels of proinflammatory biomarkers in older women and lower level of antiinflammatory biomarkers in older men. Reallocating time spent in activities of lower intensities with higher intensities was associated with lower levels of pro-inflammatory biomarkers in older women. Overall, the findings of this thesis support efforts promoting physical activity at the expense of sedentary time in order to combat age-related systemic inflammation and metabolic risk in older adults