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) behaviors on markers of systemic inflammation in older women with different levels of metabolic risk.

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 PA (LPA) and moderate-to-vigorous PA (MVPA). Blood samples were collected for the assessment of the systemic inflammatory markers C-reactive protein (CRP), fibrinogen, and adiponectin. Metabolic risk was assessed by standardized procedures based on definitions for the metabolic syndrome. Data were analyzed by linear regression models based on isotemporal substitution analysis.

Reallocating 30 min 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-min 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, whereas no impact on CRP was observed when a period of sedentary behavior was replaced with LPA. Importantly, all significant influences on fibrinogen and CRP by displacement of different PA behaviors remained after adjustment for metabolic risk status among participants. No significant associations with adiponectin were observed.

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.