Caffeine does not augment markers of muscle damage or leukocytosis following resistance exercise

The purpose of this study was to evaluate the effects of caffeine ingestion before a resistance exercise session on markers of muscle damage (CK, LDH, ALT, AST) and leukocyte levels. Fifteen soccer athletes completed two resistance exercise sessions that differed only in the ingestion of caffeine or a placebo preworkout. CK concentration increased significantly following the caffeine session (415.8+/-62.8 to 542.0+/-73.5) and the placebo session (411.5+/-43.3 to 545.8+/-59.9), with no significant differences between sessions. Similarly, LDH concentration increased significantly following the caffeine session (377.5+/-18.0 to 580.5+/-36.1) and the placebo session (384.8+/-13.9 to 570.4+/-36.1), with no significant differences between sessions. Both sessions resulted in significant increases in the total leukocyte count (caffeine=6.24+/-2.08 to 8.84+/-3.41; placebo=6.36+/-2.34 to 8.77+/-3.20), neutrophils (caffeine=3.37+/-0.13 to 5.15+/-0.28; placebo=3.46+/-0.17 to 5.12+/-0.24), lymphocytes (caffeine=2.19+/-0.091 to 2.78+/-0.10; placebo=2.17+/-0.100 to 2.75+/-0.11), and monocytes (caffeine=0.53+/-0.02 to 0.72+/-0.06; placebo=0.56+/-0.03 to 0.69+/-0.04), with no significant differences between sessions. Ingestion of caffeine at 4.5 mg/kg(-1) did not augment markers of muscle damage or leukocyte levels above that which occurs through resistance exercise alone.