Effects of eight weeks of caffeine supplementation and endurance training on aerobic fitness and body composition

The purpose of this study was to examine the effects of daily administration of a supplement that contained caffeine in conjunction with 8 weeks of aerobic training on V̇O₂peak, time to running exhaustion at 90% V̇O₂peak, body weight, and body composition. Thirty-six college students (14 men and 22 women; mean ± SD, age 22.4 ± 2.9 years) volunteered for this investigation and were randomized into either a placebo (n = 18) or supplement group (n = 18). The subjects ingested 1 dose (3 pills = 201 mg of caffeine) of the placebo or supplement per day during the study period. In addition, the subjects performed treadmill running for 45 minutes at 75% of the heart rate at V̇O₂peak, three times per week for 8 weeks. All subjects were tested pretraining and posttraining for V̇O₂peak, time to running exhaustion (TRE) at 90% V̇O ₂peak, body weight (BW), percentage body fat (%FAT), fat weight (FW), and fat-free weight (FFW). The results indicated that there were equivalent training-induced increases (p < 0.05) in V̇O₂peak and TRE for the supplement and placebo groups, but no changes (p > 0.05) in BW, %FAT, FW, or FFW for either group. These findings indicated that chronic use of the caffeine-containing supplement in the present study, in conjunction with aerobic training, provided no ergogenic effects as measured by V̇O₂peak and TRE, and the supplement was of no benefit for altering body weight or body composition.