{"id":1134,"date":"2008-12-10T11:52:59","date_gmt":"2008-12-10T10:52:59","guid":{"rendered":"http:\/\/180.211.110.195:8082\/biestmilch\/?p=1134"},"modified":"2008-12-10T11:52:59","modified_gmt":"2008-12-10T10:52:59","slug":"rinsing-out-the-mouth-with-a-carbohydrate-drink-increases-performance-performance-is-a-function-of-regulation","status":"publish","type":"post","link":"https:\/\/www.biestmilch.com\/blog\/2008\/12\/10\/rinsing-out-the-mouth-with-a-carbohydrate-drink-increases-performance-performance-is-a-function-of-regulation\/","title":{"rendered":"Rinsing out the mouth with a carbohydrate drink increases performance: performance is a function of regulation"},"content":{"rendered":"

I found this post on my favorite sport blog \u00bbthe Science of Sport\u00ab<\/a>. The results of the 2 studies cited in this post from Jonathan Dugas and Ross Tucker are very much in line with our biestmilch philosophy.<\/p>\n

In the 2004 study, cyclists had to complete a given amount of work in as fast a time as possible. This is important to note, because the mode of performance trial can influence the conclusions drawn quite substantially. In both these studies, the cyclists were able to freely select their work-rate and slow down or speed up in response to the swishing around of the carbohydrate drink or the water.<\/p>\n

The rinsing with the malto-dextrin solution improved performance by almost 3%. The immediate question arising is of course: Could this really be a metabolic effect?
\nThe usual thinking would be that glucose is superior because it is rapidly metabolised, converted to energy, and delays the onset of fatigue. This study clearly challenges that, for a number of reasons.<\/p>\n

1.
\nThe performance trial is quite short. The theory that glucose ingestion has a profound effect on performance is particularly true for long-duration exercise, where the depletion of liver or muscle glycogen may be possible.
\nThere is some evidence that glucose ingestion improves performance even during much shorter exercise trials, which is difficult to explain because only a small part of your energy comes from that ingested glucose when you do shorter, high intensity training – that was one of the reasons this study was done in the first place.<\/p>\n

2.
\nIn this study, the performance of the cyclists was better on carbohydrates from the very first quarter of the trial. So when performance is broken down, it turns out that you go faster within the first few seconds, and that clearly has nothing to do with metabolic effects.<\/p>\n

3.
\nAnother important point is that the malto-dextrin solution was chosen because it is colourless and non-sweet, which means it’s less likely to be obvious to the subjects when they’re on it – this would otherwise introduce the possibility of a large placebo effect.
\nIt turns out that some subjects did pick up the difference: Four of the nine cyclists guessed they were on the carbohydrates-trial, based on taste and viscosity. Of these four, three improved, one did worse. The placebo effect can never be ruled out, but it does seem to have been controlled as much as possible in the study.<\/p>\n

Increased central drive – feedback from the mouth, output to the muscles?<\/strong><\/p>\n

So what then is the explanation? This study did not show that rinsing the mouth is better than swallowing the solution. It simply compared rinsing with carbohydrates to rinsing with water. It therefore does not indicate that you should not drink glucose-containing drinks during exercise!<\/p>\n

However, what the study does is to help us understand how shorter exercise might be improved by carbohydrates. The authors of this study speculated that there are receptors in the mouth, which are stimulated by the cyrbohydrate-drink (but not by water), and then trigger centers in the brain that then increase the central drive for exercise.<\/p>\n

Noakes and co-workers, (Tucker and Dugas made their PhD at Noakes’ department at Cape Town University) did a lot of research on fatigue as phenomenon of the central nervous system and not the muscles. They introduced more dynamic explanatory models into sport. According to their view it is the brain (central governor) that regulates performance by controlling muscle activation in response to various cues like heat, oxygen availability etc. This carbohydrate-finding would fit in with that kind of thinking – the brain receives information from the mouth that glucose is available and it allows an increase in muscle activation. For further explanation read the Fatigue Series<\/a><\/p>\n

<\/p>\n

The ultimate outcome of this is that the perceived exertion is regulated, and performance is a function of that regulation. In other words, athletes pace themselves according to how they feel (this is obvious, I’m sure), and the rinsing with carbohydrates changes that perception, which allows them to cycle faster, and thus achieve the same perception at a higher power output (again, read the Fatigue Series<\/a> for more discussion on this)<\/p>\n

Summary<\/p>\n

The increase in performance cannot be metabolic, only sensory. Sensation (or perception) is the key component of the regulatory system where the brain monitors perceived exertion and performance.<\/p>\n

Closing I would like to quote Ross and Dugas: \u00bbThink also of the last time you went for a run or ride in very hot conditions, and what the first drink you had afterwards felt like – it’s instantly pleasurable, and that’s because of feedback to the brain, a different kind of physiology from the classic thinking that something in the body has gone “wrong”\u00ab.<\/p>\n

Carter JM, Jeukendrup AE, Jones DA: The effect of carbohydrate mouth rinse on 1-h cycle time trial performance. Medicine and science in sports and exercise, 2004 Dec;36(12):2107-11<\/p>\n

Pottier A, Bouckaert J, Gilis W, Roels T, Derave W: Mouth rinse but not ingestion of a carbohydrate solution improves 1-h cycle time trial performance. Scandinavian journal of medicine & science in sports, Nov 3, 2008<\/p>\n","protected":false},"excerpt":{"rendered":"

I found this post on my favorite sport blog \u00bbthe Science of Sport\u00ab. The results of the 2 studies cited in this post from Jonathan Dugas and Ross Tucker are very much in line with our biestmilch philosophy. In the 2004 study, cyclists had to complete a given amount of work in as fast a […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[433,437,432,1504,436,435,434],"_links":{"self":[{"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/posts\/1134"}],"collection":[{"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/comments?post=1134"}],"version-history":[{"count":12,"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/posts\/1134\/revisions"}],"predecessor-version":[{"id":1146,"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/posts\/1134\/revisions\/1146"}],"wp:attachment":[{"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/media?parent=1134"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/categories?post=1134"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.biestmilch.com\/blog\/wp-json\/wp\/v2\/tags?post=1134"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}