title: Effects of time-release caffeine containing supplement on metabolic rate, glycerol concentration and performance.
abstract: This study compared caffeine pharmacokinetics, glycerol concentrations, metabolic rate, and performance measures following ingestion of a time-release caffeine containing supplement (TR-CAF) versus a regular caffeine capsule (CAF) and a placebo (PL). Following a double-blind, placebo-controlled, randomized, cross-over design, ten males (25.9 ± 3.2 y) who regularly consume caffeine ingested capsules containing either TR-CAF, CAF, or PL. Blood draws and performance measures occurred at every hour over an 8-hour period. Plasma caffeine concentrations were significantly greater (p < 0.05) in CAF compared to TR-CAF during hours 2-5 and significantly greater (p = 0.042) in TR-CAF compared to CAF at hour 8. There were no significant differences between trials in glycerol concentrations (p = 0.86) or metabolic measures (p = 0.17-0.91). Physical reaction time was significantly improved for CAF at hour 5 (p=0.01) compared to PL. Average upper body reaction time was significantly improved for CAF and TR-CAF during hours 1-4 (p = 0.04 and p = 0.01, respectively) and over the 8-hour period (p = 0.04 and p = 0.001, respectively) compared to PL. Average upper body reaction time was also significantly improved for TR-CAF compared to PL during hours 5-8 (p = 0.004). TR-CAF and CAF showed distinct pharmacokinetics yielding modest effects on reaction time, yet did not alter glycerol concentration, metabolic measures, or other performance measures. Key pointsTime-release caffeine and regular caffeine showed distinct pharmacokinetics over an 8-hour period following ingestion.Time-release caffeine and regular caffeine yielded modest effects on reaction time over an 8-hour period following ingestion.Time-release caffeine and regular caffeine did not alter glycerol concentration, metabolic measures, or other performance measures over an 8-hour period following ingestion.
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Adam M
authors.initials: AM
authors.lastname: Gonzalez
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Jay R
authors.initials: JR
authors.lastname: Hoffman
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Wells
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Gerald T
authors.initials: GT
authors.lastname: Mangine
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Townsend
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Jajtner
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Ran
authors.initials: R
authors.lastname: Wang
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Amelia A
authors.initials: AA
authors.lastname: Miramonti
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Gabriel J
authors.initials: GJ
authors.lastname: Pruna
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: LaMonica
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Bohner
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Mattan W
authors.initials: MW
authors.lastname: Hoffman
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Leonardo P
authors.initials: LP
authors.lastname: Oliveira
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Fukuda
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Maren S
authors.initials: MS
authors.lastname: Fragala
authors.affiliation: Institute of Exercise Physiology and Wellness, Sport and Exercise Science, University of Central Florida , Orlando, FL USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Stout
keywords: Caffeine bioavailability; energy; multiple object tracking; pharmacokinetics; reaction time; sustained release caffeine