Peripheral blood samples were obtained from 11 healthy volunteers before, immediately after, and following 2 h of resting recovery from 90 min of exercise at 55%Wmax in the heat (34°C). A–F, samples were incubated with LPS (TLR4 ligand; A and B), zymosan (TLR2 and 6 ligand; C and D) or poly(I:C) (TLR3 ligand; E and F) for 6 h, following which the expression of CD86 and MHC class II was examined by flow cytometry. All data represent means ± s.e.m.†Statistically significant difference (P < 0.05) from pre-exercise. *Statistically significant difference (P < 0.05) from post-exercise.