Concept2 Forum

A sports lab in my area posted this article on their facebook page. After reading it I decided to test it on a 2 hour bike ride I was about to head out on. Not sure my dentist would be too happy, but I made a very sugary paste (a little water and 3 tablespoons of sugar) and swished it around in my mouth for 30 seconds. I spat it out and then rinsed my mouth.

Then I headed out for my ride. I have a powermeter and so I know my performance on the road very accurately (It's a $3000 crankset/computer made in Germany). I actually forgot I was under an experiment and just thinking about where I might go on my two hours. I looked down at my powermeter after about 40 minutes to check my average power as I normally would. It was reading 240watts which floored me. What? Too good to be true. With some regularity, I had been riding around 220w at best for this kind of low end tempo ride. I kept on often feeling comfortable for a few bouts 270-300w (my all out TT power). I took sips of water for the remaining 1:20 (no other carb ingested). At the end a ride I was running out of light and so headed for a local hill with little traffic to do hill climbs (1 minute at about 300 to 350w). My legs were not tired, which would be a normal effect for a long 2 hour ride at that intensity. This is clearly just one ride and one rider but I'm a believer so far. Love to hear about other's experimenting with this.


http://www.nytimes.com/2010/07/20/healt ... ise&st=cse

But the study also said that swishing it around in your mouth has no added benefit over drinking the carb solution. Unless you get cramps, wouldn't it be simpler to just drink some Gatorade beforehand? Your dentist may be slightly more approving of that approach

Good point. I think the intriguing about this that got me:

"Dr. Jeukendrup and Dr. Bridge, though, say they use the mouth-rinsing trick themselves."

Dr Jeukendrup is widely regarded in the cycling world (for many years). He's seen every little trick in the book and knows volumes about sports nutrition.

I have had issues with carbs during races and prefer the lightest stomach possible. One of the real killers for me is a feeling I'm going to toss my cookies. This may be just the thing for me. Still, very early in the experiment. Lots of variable in motion. For instance I am training more than I ever have and am on a trajectory of improvement. The sudden blip was noted.

So I got the original article this is derivative of. So it is all about receptors and this effect has been seen by researchers before. Only now can we easily do things like MRIs quickly. The paper is full of MRI images and various discussions about how the subjects perceived things like viscosity. The idea makes sense from a neurochemical stand point.

Carbohydrate sensing in the human mouth: Effects on exercise performance and brain activity
J Physiol 587.8 (2009) pp 1779–1794
Abstract:
Exercise studies have suggested that the presence of carbohydrate in the human mouth activates
regions of the brain that can enhance exercise performance but direct evidence of such a
mechanism is limited. The first aim of the present study was to observe how rinsing the
mouth with solutions containing glucose and maltodextrin, disguised with artificial sweetener,
would affect exercise performance. The second aim was to use functional magnetic resonance
imaging (f MRI) to identify the brain regions activated by these substances. In Study 1A, eight
endurance-trained cyclists ( ˙VO2max 60.8±4.1ml kg−1 min−1) completed a cycle time trial (total
work=914±29 kJ) significantly faster when rinsing their mouths with a 6.4% glucose solution
compared with a placebo containing saccharin (60.4±3.7 and 61.6±3.8min, respectively,
P =0.007). The corresponding f MRI study (Study 1B) revealed that oral exposure to glucose
activated reward-related brain regions, including the anterior cingulate cortex and striatum,
which were unresponsive to saccharin. In Study 2A, eight endurance-trained cyclists ( ˙VO2max
57.8±3.2ml kg−1 min−1) tested the effect of rinsing with a 6.4% maltodextrin solution on
exercise performance, showing it to significantly reduce the time to complete the cycle time
trial (total work=837±68 kJ) compared to an artificially sweetened placebo (62.6±4.7 and
64.6±4.9min, respectively, P =0.012). The second neuroimaging study (Study 2B) compared
the cortical response to oral maltodextrin and glucose, revealing a similar pattern of brain
activation in response to the two carbohydrate solutions, including areas of the insula/frontal
operculum, orbitofrontal cortex and striatum. The results suggest that the improvement in
exercise performance that is observed when carbohydrate is present in the mouth may be due
to the activation of brain regions believed to be involved in reward and motor control. The
findings also suggest that there may be a class of so far unidentified oral receptors that respond
to carbohydrate independently of those for sweetness.

jliddil wrote:The results suggest that the improvement in
exercise performance that is observed when carbohydrate is present in the mouth may be due
to the activation of brain regions believed to be involved in reward and motor control. The
findings also suggest that there may be a class of so far unidentified oral receptors that respond
to carbohydrate independently of those for sweetness.

I can see it now. The whole idiotic sports world will be turned upside down when they start doing a saliva carbohydrate test on every participant in every athletic event. Maybe they could call it the "sweet tooth ban."

I can hardly wait.

Bob S.

luckylindy wrote:But the study also said that swishing it around in your mouth has no added benefit over drinking the carb solution. Unless you get cramps, wouldn't it be simpler to just drink some Gatorade beforehand? Your dentist may be slightly more approving of that approach

I've read two studies: one using workers in a sugar cane field, and I can't remember what the other study was doing (cycling maybe). In any event, three groups were used: (1) just had water; (2) drank the carbohydrate drink; (3) swished the carbohydrate drink in their mouth and then spit it out. In the sugar cane study, at the beginning the workers who drank the carbohydrate drink were cutting more cane than the other two groups, but before the end, the workers who spat out the drink were leading the other two groups. The same results occurred in the other study.

Unfortunately, I threw away these studies a few months ago. Bummer. I would have liked to have provided the citations.

Doing an internet search, I keep finding the research comparing H20 and spitting out the carbohydrate drink but not comparing H20, drinking the carbo drink, and not drinking it but just spitting it out. I did come across a criticism of Dr. Mehmet Oz who allegedly repeated the sugar cane study I had read about (or perhaps this was the study?). In pertinent part: "He wanted to test whether tasting carbohydrates without swallowing them provided an energy boost, so he organized a race between three teams of suger-cane cutters. One team was allowed to drink water. The second - a tasteless carbohydrate drink that looks like water. And the third - they were allowed to swill the tasteless carbohydrate drink and spit it out without swallowing. The third team won the race, and our doctor concluded that we are so sensitized to carbs that even if our tongue only senses them, it is enough to provide an energy boost." The author thought Dr. Oz's study was simply BS, but at least this sugar cane study (one like it) is out there (even though the critic didn't post a citation -- this is from 2007). http://www.factsmart.org/mehmet/mehmet.htm

A primary concern I have is dehydration on an endurance ride or row -- even though swishing without swallowing may be superior to swallowing a carbohydrate drink, what happens if you don't drink enough liquids?

Apparently, if the athlete eats breakfast before rinsing with carbohydates or drinking a carbohydrate solution, there is no effect.

Dr. Jeukendrup and his colleagues continued to tweak the study conditions. What happened, they asked, if athletes ate breakfast before rinsing with carbohydrates, or drinking a carbohydrate solution? Then, they found, carbohydrates had no effect.

Meanwhile, neuroscientists found that rodent brains, at least, responded to carbohydrates in the mouth independently of their response to sweetness. It is carbohydrates that matter, and so artificial sweeteners do not stimulate these pathways that go from the mouth to the brain.

Then Dr. Bridge and his colleagues in Birmingham used functional magnetic-resonance imaging to determine whether glucose, which tastes sweet, has the same effect on the brain as the tasteless carbohydrate maltodextrin. They also tested artificial sweeteners for comparison. The brain scan results confirmed the exercise study results: Carbohydrates activated brain areas involved with rewards and muscle activity. Artificial sweeteners did not.

Is rinsing worthwhile for most athletes? Scott J. Montain, an exercise researcher at the United States Army Research Institute of Environmental Medicine, thinks not. The effect is real, he said, but added, "Endurance competitors are better off just consuming the calories." That way they get real fuel, instead of "sipping and then spitting out expensive, sticky spit."

Dr. Jeukendrup and Dr. Bridge, though, say they use the mouth-rinsing trick themselves.

"You do notice a benefit," Dr. Bridge said. But he noted that in a study, the athletes don't know if they are getting carbohydrates or not. "If you know you are doing it," he said, "then there's a chance it's a placebo effect."

mrfit wrote:I made a very sugary paste (a little water and 3 tablespoons of sugar) and swished it around in my mouth for 30 seconds. I spat it out and then rinsed my mouth.

I was skeptical of this method and if it would work, and also of the whole 'increased power' effect. I tried this sugar-and-water approach this evening when I got home from work for my 10k. Even though the article describes the effect being most notable in hour-long+ pieces, I did notice some extra power in my piece.

Maybe it was just the placebo effect? In either case, I took my 10K from a 36:27 to 35:47. I should note that I hadn't done one in a couple weeks and I've just started seriously picking up erging again in the last 2 months.

Either way, I'd suggest everyone gives it a try.

Thanks for the feedback everyone. These studies and inquiries about performance have a heavy burden of examination but as an athetes, let's not forget we do not need the final outcome proven to actually look into ourselves. All it has to do is be accepted as practical and effective for you. No one is saving any one's life by participating in an endurance sport!

The brain's role in fatigue is, IMO, largely ignored or simply too complex for us to place in the current paradigm. I've read enough myself to suggest that this organ will be the next boundary to explore. Read Dr. John Noakes book "The Lore of Running" for his view on why we fatigue. In a nutshell, it may simply be a protection response all managed by your little brain up there keeping us healthy and alive. You could go faster..but your brain will not let you.

Noakes book is a classic.

Here is a recent article:
The limit to exercise tolerance in humans: mind over muscle?
Eur J Appl Physiol
DOI 10.1007/s00421-010-1418-6
Abstract In exercise physiology, it has been traditionally
assumed that high-intensity aerobic exercise stops at the
point commonly called exhaustion because fatigued subjects
are no longer able to generate the power output
required by the task despite their maximal voluntary effort.
We tested the validity of this assumption by measuring
maximal voluntary cycling power before (mean § SD,
1,075 § 214 W) and immediately after (731 § 206 W)
(P < 0.001) exhaustive cycling exercise at 242 § 24 W
(80% of peak aerobic power measured during a preliminary
incremental exercise test) in ten Wt male human subjects.
Perceived exertion during exhaustive cycling exercise was
strongly correlated (r = ¡0.82, P = 0.003) with time to
exhaustion (10.5 § 2.1 min). These results challenge the
long-standing assumption that muscle fatigue causes
exhaustion during high-intensity aerobic exercise, and suggest
that exercise tolerance in highly motivated subjects is
ultimately limited by perception of effort.

Conclusion:
Muscle fatigue, perception of effort and exhaustion during other forms of exercise

We are the first to demonstrate that muscle fatigue does not cause exhaustion during high-intensity aerobic exercise. However, a similar phenomenon has been described by other authors during isometric tasks performed with iso-lated muscle groups at a relative exercise intensity (20% of MVC) (Hunter et al. 2004, 2008; Yoon et al. 2007) similar to that of our study (23 § 3% MVCP). In these studies, despite significant muscle fatigue, the MVC measured after “task failure” was well above the force required by these isometric tasks (Hunter et al. 2004, 2008; Yoon et al. 2007). Again it is clear that fatigue of the principal muscles can not explain why exercise is terminated (Enoka and Duchateau 2008). As in our study, task disengagement dur-ing these isometric tasks was associated with high RPE (Hunter et al. 2004, 2008; Yoon et al. 2007). This Wnding provides further support to the psychobiological model of exercise tolerance, and extends it to low-intensity isometric tasks performed with isolated muscle groups. Muscle fatigue seems to cause task failure only when submaximal exercise requires more intense muscle contractions (80% MVC) (Yoon et al. 2007). Examples of such activities would be resistance training or certain activities of daily living in sedentary old adults (Hortobagyi et al. 2003).