Key result
Preexercise ingestion of Monster energy drink did not significantly enhance ride time-to-exhaustion compared to placebo (45.5 vs 43.8 minutes; p=0.62).
Why the study?
Does preexercise consumption of an energy drink improve ride time-to-exhaustion or alter cardiovascular parameters in fasted subjects?
RCT (n=15)
Double-blind
randomized crossover
Does preexercise consumption of an energy drink improve ride time-to-exhaustion or alter cardiovascular parameters in fasted subjects?
Absolute Event Rate: 45.5% vs 43.8%
p-value: p=0.62
Preexercise consumption of a caffeine-containing energy drink increases resting heart rate but does not improve exercise time-to-exhaustion.
Does not support preexercise energy drink use to extend endurance; confirms lack of ergogenic benefit in fasted cyclists.
BACKGROUND: Currently, there are few studies on the cardiovascular and fatigue effects of commercially available energy drinks. This study investigated the effects of Monster energy drink (Monster Beverage Corporation, Corona, California), on resting heart rate (HR), heart rate variability (HRV), ride time-to-exhaustion, peak exercise HR, respiratory exchange ratio (RER), and peak rating of perceived exertion (RPE). METHODS: The study used a double-blind, randomized, placebo controlled, crossover design. After an 8-hr fast, 15 subjects consumed Monster Energy Drink (ED standardized to 2.0 mg * kg-1 caffeine) or a flavor-matched placebo preexercise. Resting HR and HRV were determined. After an initial submaximal workload for 30 minutes, subjects completed 10 min at 80% ventilatory threshold (VT) and rode until volitional fatigue at 100% VT. RESULTS: Resting HR was significantly different (ED: 65+/-10 bpm vs. placebo: 58+/-8 bpm, p = 0.02), but resting HRV was not different between the energy drink and placebo trials. Ride time-to-exhaustion was not significantly different between trials (ED: 45.5+/- 9.8 vs. placebo: 43.8+/-9.3 min, p = 0.62). No difference in peak RPE (ED: 9.1 +/- 0.5 vs. placebo: 9.0 +/- 0.8, p = 1.00) nor peak HR (ED: 177 +/- 11 vs. placebo: 175 +/- 12, p = 0.73) was seen. The RER at 30% of VT was significantly different (ED: 0.94 +/- 0.06 vs. placebo: 0.91 +/- 0.05, p = 0.046), but no difference between the two conditions were seen at the other intensities. CONCLUSION: Although preexercise ingestion of the energy drink does increase resting HR there was no alteration in HRV parameters. Ride time-to-exhaustion was not enhanced.
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Nelson et al. (2014) reported an RCT. Monster Energy Drink vs. flavor-matched placebo was evaluated on Ride time-to-exhaustion (minutes) (p=0.62). Preexercise ingestion of Monster energy drink did not significantly enhance ride time-to-exhaustion compared to placebo (45.5 vs 43.8 minutes; p=0.62).
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