Perceptions Of Caffeine Use Among Kansas High Intensity Functional Training Participants

Abstract

Caffeine is a psychoactive drug that decreases perceived effort and improves exercise tolerance. Yet, high-doses of caffeine can result in negative symptoms, which may affect exercise performance. High caffeine users likely perceive positive effects with caffeine-use. While high intensity functional training (HIFT) has expanded rapidly, the perceived effects of caffeine-use during HIFT is unknown. PURPOSE: To compare perceived and actual responses to caffeine during HIFT between low and high caffeine users. METHODS: Seventeen HIFT-experienced men were recruited (age = 26.9 ± 6.5 years, weight=84.7±10.1kg). Participants were randomized in a double-blind, crossover design to consume 5 mg/kg body mass of caffeine pills or placebo 60-minutes prior to a HIFT workout,. Perceptions of caffeine’s effect, successful blinding, and actual positive- and negative-symptoms were determined with surveys. Three chi-square tests were conducted to determine differences between caffeine-users (low- vs. high-users) for perceptions of caffeine’s effects (positive vs. negative), blinding to the treatment (successful vs. unsuccessful), and symptoms after caffeine supplementation (positive and negative). RESULTS: Nine participants were low-users (< 200 mg caffeine/day), and 8 high-users (> 200 mg caffeine/day). Chi-square tests were non-significant (p > 0.05). Descriptively, 2 low-users and 0 high-users perceived negative-effects, while 6 low-users and 7 high-users perceived positive-effects of caffeine use at baseline. One low-user perceived both positive- and negative-effects. Four participants from each group correctly identified the caffeine condition. After study caffeine consumption, 1 participant from each group reported negative-symptoms, while 2 low-users and 4 high-users reported positive-symptoms. CONCLUSION: No significant differences in perceived and actual responses to caffeine supplementation were found between low and high caffeine-users. However, we found that caffeine supplementation may result in negative-symptoms, so individual effects should be considered. Future studies should investigate perceived and actual responses for popular caffeinated pre-workout supplements on; specifically for negative symptoms. Funding: Kansas State University College of Human Ecology