Attenuated strength gains during prolonged resistance exercise training in older adults with high inflammatory status

Objectives: Chronic systemic low grade inflammation is associated with the age-related loss of muscle mass. Resistance exercise has been suggested to reduce or lower chronic systemic low grade inflammation. However, systemic chronic low-grade inflammation may adversely affect the adaptive response to exercise training. We investigated the effect of resistance exercise training on systemic chronic low-grade inflammation in older adults. In addition, we studied the association between systemic chronic low-grade inflammation and the adaptive response to exercise training.

Design/setting/participants: Frail and pre-frail older adults (61 subjects) performed 24 weeks of progressive resistance exercise training. Frailty was assessed using the Fried frailty criteria.

Measurements: Lean body mass (DXA), strength (1RM), circulating levels of IL-1β, IL-6, IL-8 and TNF-α were measured prior to exercise training, after 12 weeks of training, and after 24 weeks of training.

Results: Prolonged progressive resistance exercise training did not affect circulating levels of IL-6, IL-8 and TNF-α. However, exercise training led to a small but significant increase of 0.052 pg/mL in IL-1β. Higher circulating levels of TNF-α, IL-8 and IL-6 during the training period were negatively associated with strength gains for the leg press. A doubling of plasma TNF-α, IL-8 or IL-6 resulted in reduced strength gains for leg press with coefficients of -3.52, -3.42 and -1.54 respectively. High levels of circulating TNF-α were also associated with decreased strength gains for the leg extension (coefficient -1.50). Inflammatory cytokines did not appear to have an effect on gains in lean mass.

Conclusion: Our findings suggest that increased levels of plasma cytokines (TNF-α, IL-6 and IL-8) are associated with lower strength gains during resistance exercise training.