Can intervals enhance the inflammatory response and enjoyment in upper-body exercise?

Purpose To investigate the inflammatory and perceptual responses to three different forms of upper-body exercise. Methods Twelve recreationally active, able-bodied males performed three work-matched arm-crank sessions in a randomised order: 30 min moderate-intensity continuous (CON), 30 min moderate-intensity with changes in cadence (CAD) and 20 min high-intensity interval training (HIIT). Blood samples were taken pre, post and 2-h post-exercise to determine plasma concentrations of interleukin (IL)-6 and IL-1ra. Perceptual responses pre, during and following the trials were assessed using the Feeling Scale, Felt Arousal Scale, Ratings of Perceived Exertion (RPE) and the Physical Activity Enjoyment Scale (PACES). Results All trials were evenly effective in inducing an acute inflammatory response, indicated by similar increases in IL-6 after exercise and in IL-1ra at 2-h post exercise for all trials. More negative affect and higher RPE were reported during HIIT compared to CON and CAD, whereas PACES scores reported after exercise were higher for HIIT and CAD compared to CON. Conclusions When matched for external work, there was no difference in the inflammatory response to HIIT compared to moderate-intensity upper-body exercise. Although HIIT was (perceived as) more strenuous and affective responses were more negative during this mode, the higher ratings of enjoyment for both HIIT and CAD reported after exercise suggest that the inclusion of variation enhances enjoyment in upper-body exercise. As the fashion in which upper-body exercise is performed does not seem to influence the inflammatory response, it might be advised to prescribe varied exercise to enhance its enjoyment