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

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.

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

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.

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.

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.