Cytokine and adipokine response following high-intensity interval running and cycling in female adolescents.

The purpose of this study was to compare the response of cytokines, and adipokines to high-intensity interval running (HIIR) versus cycling (HIIC) in female adolescents. Eleven untrained adolescent females at post-peak height velocity, aged 15-19 years, performed two trials (HIIR and HIIC) in a randomised order. Each participant performed a progressive incremental test for each mode of exercise to determine the > 90% max workload for the trials. The trials consisted of 8 bouts of 1 min of running or cycling at > 90% maximal workload with 1 min of passive recovery in between bouts. Blood samples were collected pre-exercise, 5- and 60-min post-exercise. Pro-inflammatory TNF-α, anti-inflammatory IL-10, IL-6 (pro-/anti-inflammatory), leptin and adiponectin were measured in serum. IL-6 increased at 5 min (time-effect: β = 0.656 ± - 0.277, p = 0.032) and 60 min following exercise compared to pre-exercise (time-effect: β = 1.036 ± 0.277, p = 0.001) in both trials. IL-10 started to increase immediately after exercise (time effect: β = 0.170 ± 0.069, p = 0.025) and peaked 60 min after exercise compared to pre-exercise (time effect: β = 0.317 ± 0.069, p < 0.001). TNF-α concentrations peaked 5 min only after HIIR (interaction effect: β = 2.777, p < 0.001). No change was observed in the IL-6/IL-10 ratio, but a significant decrease was observed in the TNF-α/IL-10 ratio 60 min post-exercise (time effect: β = - 0.269 ± 0.070, p = 0.001). Leptin decreased 60 min post-exercise compared to pre-exercise in both modes (time-effect: β = 0.155 ± 0.505, p = 0.004). No change was observed in adiponectin and the adiponectin/leptin ratio. In female adolescents, high-intensity interval exercise induces an immediate, transient pro-inflammatory response accompanied by a delayed increase in anti-inflammatory cytokines and leptin, irrespective of exercise mode.