Background: This study investigated the effects of coffee ingestion with supplemental caffeine (CAF) on serum testosterone (T) responses to exercise in recreationally strength-trained males.
Methods: Subjects ingested 6 mg/kg body weight of caffeine via 12 ounces of coffee (CAF) supplemented with anhydrous caffeine or decaffeinated (DEC) coffee prior to exercise in a randomized, within-subject, crossover design. The exercise session consisted of 21 minutes of high-intensity interval cycling (alternating intensities at power outputs associated with 2.0 mmol/L lactate for two minutes and 4.0 mmol/L lactate for one minute) followed by resistance exercise (seven exercises, three sets of ten repetitions, 65% 1RM, one-minute rest periods). Subjects also completed repetitions to fatigue tests and soreness scales to determine muscle recovery 24 hours following the exercise.
Results: T was elevated immediately and 30-minutes post-exercise by 20.5% and 14.3% respectively (P<0.05). There was no main effect for treatment and no exercise x treatment interaction. There were no differences in repetitions to fatigue or soreness between treatments (P>0.05). No relationships were observed between T and any proxy of recovery.
Conclusions: While past literature suggests caffeine may enhance T post-exercise, data from the current study suggest that augmented T response is not evident following anhydrous caffeine added to coffee. The duration of T elevation indicates that this protocol is beneficial to creating long-lasting increases in serum testosterone.