Physical Activity Alters Inflammation in Older Adults by Different Intensity Levels
To examine the influence of reallocating time spent at different objectively measured physical activity (PA) behaviours on markers of systemic inflammation in older women with different levels of metabolic risk.Methods
Accelerometer-based monitoring of PA was conducted in a population of community-dwelling older women (n = 111; age = 65-70 yr) for determination of daily sedentary time, time in light (LPA) and moderate-to-vigorous physical activity (MVPA). Blood samples were collected for the assessment of the systemic inflammatory markers CRP, fibrinogen and adiponectin. Metabolic risk was assessed by standardized procedures based on definitions for the metabolic syndrome. Data were analysed by linear regression models based on isotemporal substitution analysis.Results
Reallocating 30 minutes of sedentary time with either time in LPA (β = -0.47; p<0.05) or MVPA (β = -0.42; p<0.05) was related to reduced fibrinogen level, whereas no corresponding effect was evident when shifting time in LPA with time in MVPA, while holding sedentary time constant. In contrast, reallocating a 30-minute time period in sedentary (β = -0.70; p<0.01) or LPA (β = -0.71; p<0.01) with MVPA was associated with a significant reduction in CRP level, while no impact on CRP was observed when a time period of sedentary behavior was replaced with LPA. Importantly, all significant influences on fibrinogen and CRP by displacement of different PA behaviours remained after adjustment for metabolic risk status among participants. No significant associations with adiponectin were observed.Conclusion
Altogether, this work supports the existence of different intensity thresholds mediating beneficial effects of PA on important clinical markers of systemic inflammation in older women across different stages of disease prevention.