The influence of commercial energy shots on response time and power output in recreational cyclists

Abstract

Background

Caffeine based energy shot products accounted for $1.3 billion in sales in 2011. Caffeine has been shown to confer numerous benefits during exercise and is oftentimes combined with ingredients such as carbohydrates and taurine in the hope of further performance improvement. The purpose of this project was to compare auditory response time, power output, and physiological responses between the ingestion of a CHO, PRO, caffeine supplement (CPC), a caffeine-taurine-niacin based supplement (CTN), and a placebo (PL) in commercially formulated products that make claims as to improving performance.

Methods

Fourteen subjects cycled an interval exercise of 70% VO₂max for 13 minutes and 90% of VO₂max for two minutes for a total of 120 minutes which was then followed by a six-minute power output (PO) task. Subjects ingested a total of 45 g CHO, 7.5 g PRO, and 375 mg caffeine for CPC while 512 mg caffeine and 1200 mg taurine were ingested for CTN throughout the exercise. The treatments were administered in a double blind, randomly assigned protocol. Response time was assessed by auditory response. Significance was set at p < 0.05.

Results

Average PO was significantly greater for CPC: 309 ± 60 W than CTN: 290 ± 57 W and PL: 282 ± 63 W. Response time was significantly faster for the CPC: 0.219 ± .049 s than CTN: 0.232 ± .060 s and PL: 0.228 ± .047 s. HR was significantly greater for CTN: 143 ± 16 bpm than CPC: 139 ± 16 bpm. RPE was significantly lower for CPC: 13.0 ± 1.7 than CTN: 13.5 ± 1.2 and PL: 13.8 ± 1.9. Blood glucose was greater for CPC: 5.5 ± 0.8 mM/L than CTN: 4.9 ± 0.7 mM/L and PL: 4.6 ± 1.1 mM/L. No significant differences were observed for RER.

Conclusions

The co-ingestion of CPC improved both cycling power output and auditory response time following 2 hours of moderate and high intensity interval cycling compared to CTN and PL. It is possible that the CPC treatment conferred not only a positive peripheral effect, but also a central effect. Even with a large caffeine dose, the combination of caffeine, taurine, niacin led to an inhibitory pattern which did not improve power output or response time performances over a PL.

Keywords:

• Performance
• Energy shots
• Caffeine
• Taurine
• Carbohydrates

Electronic supplementary material

The online version of this article (doi:10.1186/s12970-014-0056-5) contains supplementary material, which is available to authorized users.

Electronic supplementary material

The online version of this article (doi:10.1186/s12970-014-0056-5) contains supplementary material, which is available to authorized users.

Acknowledgements

The authors would like to thank the subjects for their efforts. This project was supported financially by PacificHealth Laboratories, Inc. PacificHealth Laboratories was not involved in study design or data analyses of this study.

Competing interests

The authors declare that they have no competing interests. JS designed protocol, completed data analysis, and took primary writing responsibilities. DC assisted in protocol design, led data collection, and assisted in assays and data analysis.

Authors’ contribution

JS designed study protocol, assisted in data collection, completed the data analyses, and led the writing of the manuscript. DC assisted in protocol design, led the data collection, directed data entry, and assisted in writing the manuscript. Both authors read and approved the final manuscript.