In this study, the hypothesis that the release of interleukin (IL)-6 from human muscle is linked to exercise intensity and muscle glucose uptake was investigated. In the overnight fasted state, seven healthy males performed knee extension exercise, kicking with both legs, each at 25 % of maximal power (Wmax) for 45 min (eliciting 23 ± 1 % of pulmonary maximal oxygen uptake, V̇O2,max) and then simultaneously with one leg at 65 % and the other leg at 85 % Wmax for 35 min (40 ± 1 % of pulmonary V̇O2,max). Blood was sampled from a femoral artery and both femoral veins, and blood flow was determined by thermodilution. Thigh plasma flow (0.15 ± 0.01, 1.4 ± 0.2, 2.0 ± 0.1 and 2.3 ± 0.2 l min−1 thigh−1 at rest and 25 %, 65 % and 85 % Wmax, respectively) and thigh oxygen uptake (0.02 ± 0.01, 0.27 ± 0.03, 0.48 ± 0.04 and 0.55 ± 0.05 l min−1 thigh−1 at rest and 25 %, 65 % and 85 % Wmax, respectively) increased with increasing exercise intensity (P