Acute Caffeine Consumption Prior to Aerobic Exercise Does Not Influence Substrate Utilization in Recreationally Trained Males and Females

Abstract

Introduction: This study aimed to examine if acute caffeine consumption influenced substrate utilization between recreationally trained males and females during submaximal aerobic exercise.Methods: Implementing a counter-balanced, crossover design study, 14 recreationally trained males (n = 7) and females (n = 7) consumed either 4 mg/kg of caffeine in 8 oz of water (CAFF) 60 min prior to aerobic exercise at varying submaximal intensities or the solitary consumption of 8 oz of water (CON). Substrate utilization was assessed via indirect calorimetry by measuring the respiratory exchange ratio. Results: There were no significant main effects for substrate utilization between sexes for the CAFF (p = .265) or CON (p = .253) trial. There were also no significant main effects for independent sex analysis between the two conditions (males, p = .917; females, p = .869).Conclusions: This study suggests no significant difference in substrate utilization between sexes when consuming caffeine. Although previous literature has indicated caffeine has the potential to increase fat utilization during moderate-intensity aerobic exercise, the current results revealed that caffeine also had no impact on substrate utilization when independently analyzing males and females.