Table 3.

Changes in plasma cytokine concentrations during exercise and recovery following caffeine supplementation

	Pre-exercise	Post-exercise	Recovery	Main effect p-values (T; C; TxC)
IL-8 (μg·mL^− 1)
Placebo	48.6 ± 4.1	59.1 ± 5.0	50.2 ± 4.6	< 0.001 ^a; 0.475; 0.290
Caffeine	49.8 ± 4.6	63.7 ± 4.4	48.6 ± 3.6	< 0.001 ^a; 0.475; 0.290
IL-1β (μg·mL^− 1)
Placebo	17.1 ± 2.7	17.4 ± 2.7	14.6 ± 3.2	0.217; 0.600; 0.293
Caffeine	16.6 ± 2.7	19.6 ± 3.0	14.8 ± 1.8	0.217; 0.600; 0.293
IL-12 (μg·mL^− 1)
Placebo	91.9 ± 6.6	113.1 ± 9.5	91.4 ± 15.1	0.007 ^a; 0.563; 0.742
Caffeine	91.6 ± 7.8	117.7 ± 9.0	77.4 ± 4.4	0.007 ^a; 0.563; 0.742
IL-1ra (μg·mL^− 1)
Placebo	2.21 ± 0.35	2.58 ± 0.52	2.30 ± 0.33	0.026 ^a; 0.577; 0.307
Caffeine	2.28 ± 0.40	2.63 ± 0.34	2.18 ± 0.55	0.026 ^a; 0.577; 0.307
IL-4 (μg·mL^− 1)
Placebo	1.74 ± 0.20	1.96 ± 0.21	1.56 ± 0.16	< 0.001 ^a; 0.522; 0.070
Caffeine	1.60 ± 0.15	2.24 ± 0.24	1.60 ± 0.18	< 0.001 ^a; 0.522; 0.070
IFN-γ (μg·mL^− 1)
Placebo	5.28 ± 0.41	6.10 ± 0.51	5.07 ± 0.67	0.015 ^a; 0.493; 0.587
Caffeine	4.73 ± 0.44	6.03 ± 0.23	4.86 ± 0.27	0.015 ^a; 0.493; 0.587

The values are the mean ± S.D. (n = 13)

T time (pre-exercise, post-exercise, recovery), C condition (placebo, caffeine), TxC interaction time x condition. Main effect for time

^aindicates significant differences post-exercise vs. pre-exercise