Exercise and inflammation with special reference to resistance training

Abstract

The aim of the present dissertation was to examine the acute and chronic effects of resistance exercise on inflammation markers in young men. In addition, the effect of combined resistance and endurance training on inflammation was assessed. The present dissertation consisted of four studies. Acute inflammation response was evaluated using cross-sectional design after hypertrophic and maximal (n=12) resistance exercise bouts (I). In addition, acute inflammation was examined before and after resistance training (RT) consisting either hypertrophic or maximal explosive (n=8) resistance exercise bouts (RE) (II). The effect of RT on basal levels of markers of systemic inflammation was evaluated after an initial phase RT after which the participants were randomly assigned to hypertrophy-strength training (n=37) or to hypertrophy-strength-power training (n=31) (III). Additionally, the effect of combined training (resistance and endurance) was evaluated after 24 weeks of training (n=48) (IV). Hypertrophic RE led to greater acute responses in inflammation markers compared to maximal strength RE (I). An enhanced MCP-1 response was observed during the recovery phase after RT in hypertrophic resistance exercise along with acute enhanced IL-1ra and reduced IL-1ǃ response. Thus, high-intensity RT modifies the RE-induced cytokine responses. Both training studies (III, IV) led to significantly improved lean mass and maximal strength as well as reduced abdominal fat mass. In the RT study (III), the initial four week phase of RT lead to increased circulating resistin, MCP-1, and IL-1ra concentrations, and decreased circulating leptin concentration. After the specialized RT periods, hypertrophy-strength RT elicited normalizing effects on inflammation markers, such as circulating resistin and leptin, whereas hypertrophy-strength-power did not have an effect on these markers. Combined training (IV) reduces concentrations of C-reactive protein, leptin, and resistin, and when performed on alternating days elicited the largest reductions in abdominal fat mass as well as circulating levels of TNF-ǂ and MCP-1. The findings of the present dissertation suggest that the beneficial effects of resistance training could be due to the repeated effect of one bout of resistance exercise on inflammation markers as well as the favorable changes in body composition following RT