Effect of Acute Caffeine Supplementation on Anaerobic Power and Blood Lactate Levels in Female Athletes

Abstract

In previous studies, most of which have been carried out on male subjects, the effect of caffeine on anaerobic performance and plasma lactate levels was equivocal. Therefore, the aim of this study was to determine the effects of caffeine supplementation on anaerobic power and plasma lactate concentration in female athletes. In this double-blind, cross-over study, 26 female basketball players were asked to attend a laboratory for three sessions. The first session was for familiarization and anthropometric measurements. In the next two sessions, the Wingate test was performed, one week apart as a washout period. Subjects performed a 30 s Wingate test, 70 min after ingestion of capsules containing caffeine (5 mg/kg) or placebo (dextrose). Blood samples were obtained after 10–12 h of fasting and 5 min post exercise for lactate measurements. The Kolmogrov–Smirnov test and paired t-test were used to analyze the data. Caffeine supplementation had no significant effect on peak/mean/end power, power drop, and fatigue index. Plasma lactate concentration significantly (p<0.001) increased in the caffeine group (from 1.72±0.58 to 4.95±0.83 mmol/L) and placebo group (from 1.66±0.73 to 5.37±0.57 mmol/L). However, the increased level in the caffeine group was significantly less than in the placebo group (p=0.01). In general, although caffeine supplementation resulted in a reduced lactate concentration in comparison with placebo, this reduction did not result in a statistically significant improvement in anaerobic power (peak/mean/end power, power drop, and fatigue index) in female athletes. Based on these findings, the administration of caffeine as a sports supplement may be effective for reducing the production of lactate during high-intensity exercise in female athletes.