Carbs & Caffeine: Science explains their synergistic effect

The Protein Work's Sports Scientist Ross Edgley takes a look at the mechanisms by which a combination of caffeine and carbs can help improve performance

In Sports Science there are many well known supplement combinations that are both proven by science and practiced by athletes. But one that continually makes the headlines of Sports Science Journals is the simple carbohydrate and caffeine combo. Here the Sports Scientists from www.theproteinworks.com look at the findings from recent research conducted at the Department of Sport, Faculty of Health & Wellbeing at Sheffield Hallam University and explain the mechanisms by which caffeine and carbs can help improve performance.

The study:

The research conducted at Sheffield Hallam University set out to determine the synergistic effects of carbohydrate and caffeine supplementation on sports performance. This is following years of research that showed individually carbohydrates were able to improve endurance by increasing muscle glycogen levels whilst caffeine was able to improve mental alertness and perception to fatigue by positively affecting neurotransmitters. But lead researcher Mayur Ranchordas believes that combining the '2 could lead to a synergistic effect for athletes.'

Findings: 

To determine the effect of co-ingesting a carbohydrate and caffeine drink, Ranchordas and his team gave athletes a carbohydrate/caffeine drink (6.4% carbohydrates plus 16mg of caffeine) and then compared it to a carbohydrate drink (solely 6.4% carbohydrates) whilst they completed intervals of sprints for 90 minutes. The tests were completed 7 days apart to allow for sufficient rest.

Results found that whilst endurance levels were similar in both, the carbohydrate plus caffeine drink allowed athletes to sustain higher workout intensities (i.e. a flat out sprint) for longer which was demonstrated and tested with elevated blood lactate levels.

So where exactly do the performance enhancing benefits of the carbohydrate caffeine combination come from?

Reduces perception to fatigue: 

Research conducted at the Division of Sport and Exercise Science at the University of Luton found that caffeine was able to reduce an athlete's perception to fatigue during exercise (M. Doherty and P. M. Smith, 2005).  Experts believe it does this by stimulating the production of the neurotransmitter beta-endorphin and this may explain why, when caffeine is coupled with carbohydrate supplementation to ensure muscle glycogen levels are fully topped up, athletes are able to maintain a higher intensity and maximal output for longer.

Spares muscle glycogen:

As far back as 1980 it was theorised and published in the International Journal of Sports Medicine that taking caffeine with carbohydrates has been shown to spare your muscle glycogen stores by encouraging your body to burn stored fat as fuel, essentially saving your muscle glycogen for those maximal intensity sprints. 

Creates a more favourable ionic environment within the muscle:

Finally research conducted at the University of Guelph in Ontario, Canada found that caffeine supplementation could 'permit an athletes to train at a greater power output and/or to train longer by producing a more favourable ionic environment within the active muscle.' This combined with the obvious benefit of having sufficient carbohydrates (your muscles primary source of fuel) means this too is another mechanism by which caffeine and carbohydrates helps your muscles perform at a higher intensity for longer.

Sourcing Carbohydrates & Caffeine

So does this mean a slice of toast and a strong coffee before training will make me run like Mo Farah? Well in theory yes.

References:

• M K Ranchordas, P Pattison (2011) 'Effects of carbohydrate and caffeine co-ingestion on a reliable simulated soccer-specific protocol.' British Journal Of Sports Medicine, 2011, 45
• M. Doherty and P. M. Smith (2005) 'Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta-analysis.' Scandinavian Journal of Medicine & Science in Sports, Volume 15, Issue 2, pages 69–78, April 2005
• D. Essig, D. L. Costill and P. J. Van Handel (1980) 'Effects of Caffeine Ingestion on Utilization of Muscle Glycogen and Lipid During Leg Ergometer Cycling.' International Journal Of Sports Medicine.