The purpose of this study was to determine the effects of creatine supplementation on blood lactate during incremental cycling exercise.
Thirteen male subjects (mean ± SD: 23 ± 2 years; 178.0 ± 8.1 cm; 86.3 ± 16.0 kg; 24 ± 9 % body fat) performed a maximal, incremental cycling test to exhaustion before (Pre) and after (Post) 6-days of creatine supplementation (4-doses per day of 5 g creatine + 15 g glucose). Blood lactate was measured at the end of each exercise stage during the protocol, and the lactate threshold was determined as the stage prior to achieving 4 mmol·L-1. Lactate concentrations during the incremental test were analyzed using a 2 (condition) x 6 (exercise stage) repeated measures ANOVA. Differences in power at lactate threshold, power at exhaustion, and total exercise time were determined by paired t-tests and are presented as means ± SD.
Lactate concentrations were reduced during exercise following supplementation, demonstrating a significant condition effect (p = 0.041). There was a tendency for increased power at the lactate threshold (Pre: 128 ± 45 W; Post: 143 ± 26 W; p = 0.11). Total time to fatigue approached significant increases (Pre: 22.6 ± 3.2 min.; Post: 23.3 ± 3.3 min.; p = 0.056), as did maximal power output (Pre: 212.5 ± 32.5 W; Post: 220 ± 34.6 W; p = 0.082).
Our findings demonstrate creatine supplementation decreases lactate during incremental cycling exercise and tends to raise lactate threshold. Therefore, creatine supplementation could potentially benefit endurance athletes.