A 10K isn’t typically thought of as a distance that requires too much of a race nutrition plan. Strategies involving carbohydrate ingestion are usually the focus of runners competing in half marathon distances and above, but recent research over the past few years has revealed that ingesting just a sip of a sports drink during short term intense exercise (like a 10K race) may also lead to improved performance.(1-6) Here’s the real kicker…you don’t even have to swallow the drink to realize the benefit—simply swishing a carbohydrate solution around in your mouth and then spitting it out is sufficient.
I have to admit I was pretty captivated (and also a little skeptical) when I first heard the claims that simply mouth rinsing with a carbohydrate could be ergogenic. It’s long been known that ingesting carbohydrates during exercise lasting longer than 2 hours delays fatigue and boosts endurance performance by mechanisms that are complex (more than just sparing glycogen) and likely due to a combination of metabolic as well as non-metabolic factors. Even activities lasting 1-2 hours but at a high intensity (basketball, soccer, sprint triathlon, etc) benefit from carbohydrate ingestion. In exercise lasting less than 1 hour however, when adequate stores of muscle glycogen are still available, carbohydrate intake was thought to be unnecessary and of little benefit to the athlete. New emerging evidence though, may be shedding a different light on the story with short term exercise… and it’s not really all that surprising to hear. Our brains play a much larger role in endurance performance than previously thought.
The idea of ‘central nervous fatigue’ was first being talked about in the late 90’s. This hypothesis (also referred to as the central governor theory) argues that the brain, rather than the body, limits endurance performance. In other words, we don’t stop exercise because we’re taxed physiologically (out of glycogen, high lactate levels, etc) and at our physical limit–we slow down and stop exercise because our brain is constantly monitoring exercise intensity so as prevent our bodies from being completely taxed physiologically and causing harm. It’s the brain’s protective mechanism to ensure there’s always a little left in reserve (sort of like an emergency buffer) in order to avoid irreparable physiological damage.
So getting back to the main topic on hand, we can essentially trick the brain and allow ourselves to work harder during a 10K when we might normally be starting to slow down by taking in a small sip of a sports drink or energy gel. How? When carbohydrate is present in the mouth, specific receptors sensitive to carbohydrate send a signal to reward centers in the brain involved in motivation, behavior and emotion. A lowering of the perception of effort is thought to be an additional effect.(3-5). So by ingesting a swish of a sports drink or gel during the race you’re basically telling the brain, “Fuel is on the way, so you can push a little harder.” More practically speaking, if your perception of effort running at a specific pace (7:00 min/mile for example) during the race is lowered, then you can presumably increase your pace (say 6:55 min/mile) to a workload that you normally associate with a 7:00 min/mile effort level. This increase in running speed would therefore lead to an improvement in your finish time.
What amount of carbohydrates are we really talking about? A ‘sip’ is pretty accurate. Volumes used in the studies corresponded to 25mL, which is comparable to 2 tablespoons of a sports drink or 1 tablespoon of an energy gel. So if you’re an athlete that sometimes experiences GI/stomach issues with sport nutrition products and are therefore hesitant to reach for a cup of sports drink at an aid station, then the mouth rinsing strategy could be just what you’re seeking. You can reap the benefits whether you choose to swallow the sip or spit it out after a few seconds.
In summary, the old saying of ‘running being 90% mental’ may not be too far off the mark, so don’t completely ignore your carbohydrate needs for the shorter races you may be participating in during the next few hot summer months. A little boost in intensity (i.e pace) can translate into a significant improvement in your performance.
Note: The 2012 Peachtree Road Race will be handing out Powerade and water at aid stations located each mile along the race route. You may also plan ahead and bring your own source of carbohydrates if you plan on trying this nutrition strategy out on July 4th.
Holly Ortlund is a member of the ATC Women’s Competitive Team and recently founded www.energygelcentral.com, a website dedicated to helping educate athletes about sport nutrition products.
References:
Beelen M, Berghuis J, Bonaparte B, et al. Carbohydrate mouth rinsing in the fed state does not enhance time trial performance. Int J Sports Nutr Exerc Metab 2009; 19 (4): 400-9
Carter JM, Jeukendrup AE, Mann CH, et al. The effect of glucose infusion on glucose kinetics during a 1-h time trial. Med Sci Sports Exerc 2004; 36 (9): 1543-50
Chambers ES, Bridge MW, Jones DA. Carbohydrate sensing in the human mouth: effects on exercise performance and brain activity. J Physiol 2009; 578 (8): 1779-94
Rollo I, Williams C. Influence of ingesting a carbohydrate electrolyte solution before and during a 1-hour run in fed endurance-trained runners. J Sports Sci 2010; 28 (6): 593-602
Rollo I, Williams C. Effect of mouth-rinsing carbohydrate solutions on endurance performance. Sports Med 2011: 01 (6): 449-401
Pottier A, Bouckaert J, Gilis W, et al. Mouth rinse but not ingestion of a carbohydrate solution improves 1-h cycle time trial performance. Scand J Med Sci Sports 2010; 20(1): 105-11
Whitham M, McKinney J. Effect of a carbohydrate mouthwash on running time-trial performance. J Sports Sci 2007; 25(12): 1385-92
