Big-branded energy drinks containing added caffeine are booming – with net sales of the world’s most popular brand often exceeding £4 billion.
But how do such drinks stack up in terms of enhancing sport performance? And are they any better than consuming a caffeine supplement in (a cheaper) tablet form washed down with carbohydrate drink?
To answer this, scientists have compared the effects of a commercial energy drink (Red Bull) with an equivalent dose of caffeine in tablet form on the cycling performance of 11 trained male cyclists.
In this study (a double-blind, placebo-controlled cross-over design – the most rigorous type), the cyclists performed three separate 1hr time-trials, and 90mins before each trial they consumed one of the following:
■ Red Bull
■ Caffeine tablets plus a carbohydrate drink
■ A plain carbohydrate drink
To allow for a proper comparison, the cyclists consumed the same amount of carbohydrate (just over 1g per kilo of bodyweight) and fluid (9.4ml per kilo) in all three trials.
Also, the caffeine dose was set so that it was identical (at 3mg per kilo of bodyweight) in the Red Bull and caffeine tablet trials.
Compared to the carbohydrate-only drink trial, the cyclists rode faster when they had taken caffeine – both the carbohydrate plus caffeine tablet and Red Bull trials were significantly faster.
When they took caffeine tablets plus the carbohydrate drink, they knocked 120secs off. Drinking Red Bull resulted in a 109sec improvement. The slight difference in improvements between these two trials was not considered significant.
Because the two caffeine results were so similar, however, the researchers concluded that it was the caffeine in the Red Bull that had produced performance gains over a standard carbohydrate drink, and that the other ingredients (for example an amino acid called taurine) did not offer any additional benefit.
This study demonstrates that adding caffeine to carbohydrate produces greater performance improvements than consuming carbohydrate alone – and it doesn’t matter what form the caffeine comes in.
It also fits with other studies showing that around 3mgs of caffeine per kilo is a very effective caffeine dose to enhance endurance performance (see refs).
Takeaway tips
■ Caffeine taken before exercise is effective at enhancing performance but for those sensitive to energy swings and dips, it’s best to begin consuming carbohydrate once on the move.
■ Use a proper caffeine supplement to provide your pre-exercise caffeine. Don’t rely on tea/coffee as the caffeine contents in these drinks can vary wildly.
■ For races/training sessions over an hour or longer, stick to a caffeine dose of 2-3mg/kg. There’s no evidence that higher doses produce additional performance gains.
(Images: iStockPhoto / Remy Whiting)
References: Int J Sports Physiol Perform. 2015 Feb 24. (epub ahead of print). ‘Other studies’: J Appl Physiol 1998; 85:709-715 and J Sports Sci. 2012;30(2):115-20