Writing in the Journal of Caffeine Research, Lassiter et al. set out to investigate the effectiveness of an energy drink (in this case Monster Energy) on cycling performance, cognitive performance at rest, during moderate exercise and straight after a 35km cycling time trial using an ergometer.
15 subjects (seven female) were each treated with (A) A 480ml, 200kcal Monster Energy drink with caffeine (160mg), carbohydrate (54g), taurine (2g) and panax ginseng (400mg) and (B) a caffeine-free non-caloric placebo beverage (PLA) of the same size with 0kcal, no caffeine, herbals or amino acids.
Both drinks – served chilled in opaque water bottles – were provided by Monster Energy Corporation, and were of a similar taste, texture and color.
Significant performance boost
Results showed that race performance improved by 3% on average in both LO and HI groups – three women and two men in the HI category had elevated baseline blood caffeine levels of over 1000ng/ml) when subjects drank energy drinks instead of the placebo beverage.
And although VO2 (maximal oxygen consumption) and heart rate levels were greater throughout the race for energy drink versus the placebo, there was no difference in perceived exertion between treatments, while the former increased taps/second in a tapping task before and after exercise.
Summing up their results, Lassiter et al. wrote: “It seems reasonable to conclude that athletes may benefit from consuming an appropriate amount of energy drinks prior to competition.
“Follow-up research will help identify the relative contributions and interactions of the energy drink ingredients in improving aerobic endurance and speed of movement.”
Caffeine accounts for effects?
The researchers said that Ivy et al. (2009) found improvements in time trial performance after Red Bull supplementation, while Alford et al. (2001) showed that drinking Red Bull resulted in enhanced ability to sustain work output at an exercise intensity eliciting 65-75% of maximal heart rate.
But although this study and others showed beneficial effects of caffeine on exercise performance, Lassiter et al. said the impact of so-called ‘withdrawal reversal’ (whereby regular caffeine consumers suffer withdrawal symptoms prior to trials, which are then reversed) should be considered in future.
Discussing the mechanism of action for the observed effects, the scientists said they could not rule out performance improvements due to presence of carbohydrates or additional micronutrients.
It seemed unlikely that caffeine alone was responsible for the average 3% performance increase among subjects, the team said, given that five subjects had elevated baseline blood caffeine levels.
But the team said a case could be made for caffeine as the primary effect provider, since carbohydrate supplementation in the hour before exercise had not been found to improve aerobic exercise in previous studies, whereas caffeine consumed in this timeframe had consistently done so.
Title: ‘Effect of an Energy Drink on Physical and Cognitive Performance in Trained Cyclists’
Authors: Lassiter, D.G., Kammer, L., Burns, J., Zhenping, D., Heontae, K., Joowon, L., Ivy,J.
Source: Journal of Caffeine Research, Vol. 2, No.4, 2012 (published February 19 2013), DOI: 10.1089/caf.2012.0024