Researchers from our Department for Health have shown for the first time that ingesting a carbohydrate sports drink during an Olympic-distance triathlon improves performance.
The researchers from the Human Physiology Research Group set out to examine whether a carbohydrate drink had a greater effect than a flavoured-water placebo when given to triathletes.
Olympic-distance (OD) triathlon is a multidisciplinary sport that involves a 1500m swim, a 40km cycle and a 10km run performed in immediate succession, placing a heavy demand on the body’s limited energy supplies.
Triathletes need to carefully design their nutritional strategy in terms of what, when and how much to consume during the event.
Only one previous study, carried out over twenty years ago, looked at carbohydrate ingestion during triathlon and found it to not have any significant benefit.
However, carbohydrate is the major fuel source during exercise and is well established as an aid to physical performance during single discipline events like swimming, cycling and running.
Now Dr Kerry McGawley, who led the study along with Dr James Betts and University of Bath graduate Oliver Shannon, found that by increasing the amount of carbohydrate ingested during the cycle ride resulted in a four per cent improvement in the running event.
Dr McGawley said: “This is the first study to show a significant improvement in triathlon performance with carbohydrate ingestion.
“We showed that ingesting a relatively high concentration of carbohydrates, as opposed to taste-matched water during the cycle section, resulted in a significant improvement in subsequent run performance.”
— Dr Kerry McGawley
The swim and cycle sections of the main trials were of fixed intensities, with the carbohydrate or sugar-free fruit flavoured drinks ingested every quarter of the way through the cycle section, as this is when triathletes typically take the opportunity to take on board fuel.
It was then during the final run section when participants’ time trial performances were assessed as, especially in OD triathlon, this tends to be the section where the race is won or lost (i.e. participants tend to ‘bunch-up’ and draft behind one another during both the swim and the cycle sections).
Blood samples were collected at frequent intervals during each trial to assess participants’ metabolic responses to each treatment during exercise.
Dr James Betts added: “It may be that the quantity of carbohydrate required to elicit statistically significant improvements in performance is greater than that which has been shown to produce some degree of ergogenic effect during single-discipline events.”
Additional aspects of this experiment that add to the practical ‘real-world’ value, particularly with relevance to London 2012, are that performance was tested in both male and females triathletes who were in a fed-state following a standardised breakfast and performed at temperatures typical to London at this time of year.
The paper published Applied Physiology, Nutrition and Metabolism can be viewed here.