L
Lyndon
Guest
ignoramus26859 wrote:
>In article <vgi2d.203685$Fg5.145484@attbi_s53>, Bear G wrote:
>> Donovan Rebbechi wrote:
>>>>Is it possible to do on a low carb diet, given that I am in a reasonable
>>>>average condition?
>>
>> The problem is muscle glycogen levels. I can't remember if I saw
>> the link here or in a *Fit forum but there's a paper out that
>> compares muscle glycogen levels in three groups. As I recall:
>>
>> carboloaded runners: 60-70 (mg/g?)
>> average diet runners: 35-40
>> low-carb diet: 15
>>
>> You need muscle glycogen to burn fat, and you can't refresh it
>> fast enough by eating energy gels. (That doesn't mean they're
>> worthless, just not enough to allow you to run indefinitely.)
>> Once your muscle glycogen is exhausted you bonk.
>
>That would be for anaerobic workouts, no?
>
For aerobic OR anaerobic workouts, the primary source of energy is glycogen,
which is what you deny yourself on a low carb diet.
>For aerobic workouts, glucose is supplied to muscles continuously, as
>are fatty acids. Am I mistaken?
>
Part of the glycogen is stored in the muscle tissue and part comes from the
bloodstream. For longer (over 30 minutes) aerobic activity, part of the energy
comes from fat from the bloodstream. If your glycogen stores are reduced due
to poor diet (i.e. low carb), then much more of the energy you consume during
exercise must come from fat sources, or you will hit the wall. The speed you
can run off primarily fat is MUCH slower than the speed you can run off mostly
glycogen.
>Thanks. My purpose really is to find how far can I go while being on
>an LC diet... So, quite possibly, I would achieve suboptimal results
>(time to run the half marathon) while on LC, however, it would be
>actually a more interesting experiment to me. "can I run half marathon
>on LC"
>
It is not necessarily during a single long run where the effects of the
low-carb diet is seen. If you run a single long run VERY slowly, you can
likely do this for 1-2 hours, consuming enough fat to keep your diminished
glycogen stores from striking zero. But there ia acatche here:
Dr. David Costil, in his book, "Inside Running: The Basics of Sports
Physiology" (page 63) has a chart showing the difference on glycogen stores
from a low versus high carb diet while training everyday. You need 6-10 g/kg
of carbs every day to keep your glycogen stores up. If you get much less than
this--and you can't recover the carbs you expended in your last workout from
your diet before your next workout--your glycogen stores will gradually decline
EVERY DAY until you finally bonk. It isn't necessarily any one training
session that will kill you; It is the cumulative effect of a training program.
Lyndon
"Speed Kills...It kills those that don't have it!" --US Olympic Track Coach
Brooks Johnson
>In article <vgi2d.203685$Fg5.145484@attbi_s53>, Bear G wrote:
>> Donovan Rebbechi wrote:
>>>>Is it possible to do on a low carb diet, given that I am in a reasonable
>>>>average condition?
>>
>> The problem is muscle glycogen levels. I can't remember if I saw
>> the link here or in a *Fit forum but there's a paper out that
>> compares muscle glycogen levels in three groups. As I recall:
>>
>> carboloaded runners: 60-70 (mg/g?)
>> average diet runners: 35-40
>> low-carb diet: 15
>>
>> You need muscle glycogen to burn fat, and you can't refresh it
>> fast enough by eating energy gels. (That doesn't mean they're
>> worthless, just not enough to allow you to run indefinitely.)
>> Once your muscle glycogen is exhausted you bonk.
>
>That would be for anaerobic workouts, no?
>
For aerobic OR anaerobic workouts, the primary source of energy is glycogen,
which is what you deny yourself on a low carb diet.
>For aerobic workouts, glucose is supplied to muscles continuously, as
>are fatty acids. Am I mistaken?
>
Part of the glycogen is stored in the muscle tissue and part comes from the
bloodstream. For longer (over 30 minutes) aerobic activity, part of the energy
comes from fat from the bloodstream. If your glycogen stores are reduced due
to poor diet (i.e. low carb), then much more of the energy you consume during
exercise must come from fat sources, or you will hit the wall. The speed you
can run off primarily fat is MUCH slower than the speed you can run off mostly
glycogen.
>Thanks. My purpose really is to find how far can I go while being on
>an LC diet... So, quite possibly, I would achieve suboptimal results
>(time to run the half marathon) while on LC, however, it would be
>actually a more interesting experiment to me. "can I run half marathon
>on LC"
>
It is not necessarily during a single long run where the effects of the
low-carb diet is seen. If you run a single long run VERY slowly, you can
likely do this for 1-2 hours, consuming enough fat to keep your diminished
glycogen stores from striking zero. But there ia acatche here:
Dr. David Costil, in his book, "Inside Running: The Basics of Sports
Physiology" (page 63) has a chart showing the difference on glycogen stores
from a low versus high carb diet while training everyday. You need 6-10 g/kg
of carbs every day to keep your glycogen stores up. If you get much less than
this--and you can't recover the carbs you expended in your last workout from
your diet before your next workout--your glycogen stores will gradually decline
EVERY DAY until you finally bonk. It isn't necessarily any one training
session that will kill you; It is the cumulative effect of a training program.
Lyndon
"Speed Kills...It kills those that don't have it!" --US Olympic Track Coach
Brooks Johnson