Glycogen depletion and training adaptations

I'm totally fascinated by the fracas surrounding Dr. Pedersen's thoughts on training in a glycogen depleted state. To make a long story short, it seems that some training adaptations might be facilitated by training in a glycogen-depleted state. See, e.g., http://www.sportsci.org/2006/ss.htm or the more pop-sciencey http://www.poweringmuscles.com/article.php?article_id=160.

I'm extremely curious to hear folks thoughts on this matter. As Stephen Seiler points out above, this does seem to resolve part of the mystery of how athletes in earlier times seemed to train so little. On an anecdotal note, it jibes with some personal experience I've had of riding in energy deficits. Carbohydrate stores certainly wouldn't be the first acute performance enhancer that can inhibit performance chronically; after all, rest behaves the same way.

Read all of the other articles on that site. They suggest also that you should not compete in a gylcogen depleted state.

http://www.poweringmuscles.com/artic...?article_id=14

Edit: The site above is a commercial front for Accelerade (as I read it more). So, take it with a grain of salt (sic).

Train depleted so you set your self up for diabetes.

Says who? Any evidence for that claim?

read here secound post by Ric Stern. http://www.cyclingforums.com/t276533.html

Then keep reading, and notice that when I asked him for a source for that rather alarming claim, I was met with deafening silence. I don't even understand what mechanism would cause this; shouldn't bonking increase insulin sensitivity? Or is the idea that your body would try to compensate for occasionaly hypoglycemia by chronically increasing its "set point" for blood sugar, leading to diabetes?

Ric is a sports scientist i will take his word on this. sorry i don't know the answer to your questions. but i don't see what sense it makes to train depleted, in a haze feeling like ****. if there was some benefit to it, i think sports scientist and coaches would clue the world in on that.

Alright, so, as far as I can tell, there is no evidence for the claim. Case closed.

P.S.: We may also note that nobody in this thread has mentioned bonking at all. At least I did not understand "glycogen-depleted" as synonymous with "bonked". I understood it to simply mean that we allow the glycogen stores to be drawn down to lower levels, but not to the level of bonking (meaning, essentially, level zero). Otherwise, I find it hard to imagine that much good will come out of training while you're at a point where you have to limp home at 10mph...

Well, the problem is that he did not have anything to say on that topic, once asked.

Neither do I. This may be a point of misunderstanding, as I wrote in my post above. Can anybody confirm that we are to understand "glycogen-depleted" as meaning "bonked"?

There have been reports of some pros who experienced many episodes of bonking then found that they experienced future episodes more readily, with less apparent depletion before feeling bonked. I don't know, but I think I've seen this linked to similarities with diabetes but I don't know of anyone actually getting diabetes from bonking. It might just be that people pre-disposed to diabetes were earlier pre-disposed to bonking, so, not cause and effect.

My coach tells me that it is not uncommon for pros to go out for 4-5 hours on Mondays (after weekend races) and ride with very little carbohydrate fueling, suppposedly to enhance their fat for fuel mechanisms.

Riding with insufficient carbs is also a good way to encourage the use of protein for fuel...

Which proteins go first? Cellular membranes...Muscle tissue...brain cells....

Is there a correlation between "low-carb" cyclists and low-brain cell cyclists?

Indeed. I only take it somewhat seriously out of a deep respect for Ric, whom I've never known to just drop something like that from out of nowhere.

Correct. "Bonking" has nothing to do with the study in question; the experimental group simply worked out with less replete glycogen stores than the control group (and so saw more expression of the IL6 gene, which mediates some, but far from all, of skeletal muscles' adapatations to endurance exercise). I found what I believe to be the actual study on Dr. Pedersen's web site: http://www.bkpgroup.dk/Reprints/Repr...%20exercis.pdf

Nobody's "bonking", here. Instead, she's comparing doing X amount of training in a glycogen replete state with doing X/2 in glycogen repletion, and X/2 a few hours later, before glycogen stores are fully replaced.

Silence: I don't know -- maybe i went coaching or training straight after the initial reply (the reply looks rushed so maybe i was doing something else), perhaps i went on holiday, or maybe i was working? I've no idea why i didn't respond. maybe i didn't even receive notification of further messages (which has happened in the past).

If you feel that i've not answered something as fully as you'd like and i haven't responded further, the best thing is to shoot me a private message or email and let me know that there needs to be more of a response. In all honesty i can only spend a certain amount of time here, as i need to work and do other stuff, otherwise i'd have to keep checking out the forums *all* the time!

As regards the mechanism for the potential diabetes, other than what Warren stated I don't have much more to add. In the case of that answer i was just passing on some info i'd been given by Andy C, who suggested it to me.

cheers
ric

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http://www.cyclecoach.com

Muscle. It is the primary reservoir of protein in the body, and in fact survival in disease processes (including starvation) is directly related to maintenance, or lack thereof, of muscle mass.