Re: Lactic acid and exercise

[Guest guest]

-

> " Lactic acid is actually a fuel, not a caustic waste product. Muscles

> make it deliberately, producing it from glucose, and they burn it to

> obtain energy. "

>

> Interesting eh?

Yeah, my understanding is that the association of muscle fatigue with

a buildup of lactic acid has turned out to basically be a myth. A

significant part of the problem actually involves the muscle simply

getting too hot to function properly, but there are other issues too,

many of which we're probably not yet aware of.

-

[Guest guest]

But years ago Discover magazine had a medical story about a

phenomenon where if you REALLY exercise too much the lactic acid will

build up to levels that are toxic. Their story was about a push-up

competition in which the man overdid it so much he nearly died. Hmmm.

What bugs me about scientists is the seem so sure they have the right

answer but they're always contradicting each other... LOL!

--- In , Idol <Idol@...>

wrote:

>

> -

>

> > " Lactic acid is actually a fuel, not a caustic waste product.

Muscles

> > make it deliberately, producing it from glucose, and they burn it

to

> > obtain energy. "

> >

> > Interesting eh?

>

> Yeah, my understanding is that the association of muscle fatigue

with

> a buildup of lactic acid has turned out to basically be a myth. A

> significant part of the problem actually involves the muscle

simply

> getting too hot to function properly, but there are other issues

too,

> many of which we're probably not yet aware of.

>

> -

>

>

[Guest guest]

They might have just been assuming because the lactic acid theory

isn't challenged by most of the 'world of science'.

" Mitochondria even have a special transporter protein to move the

substance (Lactic Acid) into them, Dr. found. Intense training

makes a difference, he said, because it can make double the

mitochondrial mass. "

That finding seems important. If there is something to carry it into

mitochondria it should not be a waste product by any means.

-

> >

> > -

> >

> > > " Lactic acid is actually a fuel, not a caustic waste product.

> Muscles

> > > make it deliberately, producing it from glucose, and they burn it

> to

> > > obtain energy. "

> > >

> > > Interesting eh?

> >

> > Yeah, my understanding is that the association of muscle fatigue

> with

> > a buildup of lactic acid has turned out to basically be a myth. A

> > significant part of the problem actually involves the muscle

> simply

> > getting too hot to function properly, but there are other issues

> too,

> > many of which we're probably not yet aware of.

> >

> > -

> >

> >

[Guest guest]

This article doesn't make any sense to me.

First of all, the fact that lactic acid can be used for fuel when you

consume it is not in conflict with the idea that lactic acid is bad

when your muscles make it. Muscles make lactic acid from pyruvate

when their production of pyruvate exceeds their oxidative capacity.

So, the production of lactate indicates that your oxidative capacity

is not meeting your demand for energy. Regardless of whether the

lactate is directly toxic to the cells, it is a marker for deficient

oxidative capacity.

Second, lactate can be used for fuel when the oxidative capacity of

the cell is sufficient to oxidize it. The production of lactate by

muscles ipso facto demonstrates that the muscles can't use the lactic

acid. If they could, they would not have made it in the first place.

Third, the mainstream doctrine is not represented in this article,

which is that the lactate produced by the muscles is used by the

*liver.* Instead, this article asserts that it is used by the muscle,

without presenting any evidence of such, and despite the fact that it

doesn't make any sense.

Finally, I do not know if it is true that lactate is toxic to muscle

cells, but I don't see how this article presents evidence otherwise.

I would be kind of surprised if a buildup of any acid was not toxic to

a cell since it is, well, a buildup of acid. Also, Ray Peat says that

a buildup of lactic acid in the blood carries adverse effects because

it causes CO2 loss, which has a number of adverse effects, including

decreasing oxygen delivery to tissues. I don't know how good the

evidence is for this dynamic but it is an additional possibility to

consider.

Chris

[Guest guest]

On 3/4/08, gdawson6 <gdawson6@...> wrote:

> They might have just been assuming because the lactic acid theory

> isn't challenged by most of the 'world of science'.

>

> " Mitochondria even have a special transporter protein to move the

> substance (Lactic Acid) into them, Dr. found. Intense training

> makes a difference, he said, because it can make double the

> mitochondrial mass. "

>

> That finding seems important. If there is something to carry it into

> mitochondria it should not be a waste product by any means.

Perhaps decades ago there were people who thought that lactic acid

could not be used for energy and was simply a toxin, but there is no

one who believes this now, so this doesn't challenge the " world of

science. " The lactate taken in by the mitochondria is probably

converted to pyruvate and then used just like the pyruvate derived

from glucose. In the liver, it can be used to make glucose which can

be sent back to exercising muscles to burn for energy. But, obviously

the same cells turning pyruvate into lactate are not going to turn it

right back into pyruvate. First, because they can't, and second,

because there would be no point in making the lactate in the first

place.

Chris

[Guest guest]

Ya, well if low oxygen and lactic acid appear pretty much

simultaneously, it would seem to me that the lactic acid is a backup

system for energy production....in which case the lack of oxygen would

also have a variety of other effects on the whole body...and you would

just have to find the best way to increase oxygen to your cells...most

likely through healthy diet and something like sprinting if I am

thinking properly.

Many mechanisms seem still unknown, but its really hard to find the

cause and effect in the statement Ray Peat said regarding lactic acid.

Yes it may build up but isn't oxygen already low at that point in the

muscles? It would seem that the lactic acid backup energy production

would seem to further exacerbate the problem if that statement was

true...but it doesn't explain why athletes seem to do better with less

muscle cramps after drinking pickle brine with lactic acid...because

that would also raise blood lactate levels right?

-

>

> This article doesn't make any sense to me.

>

> First of all, the fact that lactic acid can be used for fuel when you

> consume it is not in conflict with the idea that lactic acid is bad

> when your muscles make it. Muscles make lactic acid from pyruvate

> when their production of pyruvate exceeds their oxidative capacity.

> So, the production of lactate indicates that your oxidative capacity

> is not meeting your demand for energy. Regardless of whether the

> lactate is directly toxic to the cells, it is a marker for deficient

> oxidative capacity.

>

> Second, lactate can be used for fuel when the oxidative capacity of

> the cell is sufficient to oxidize it. The production of lactate by

> muscles ipso facto demonstrates that the muscles can't use the lactic

> acid. If they could, they would not have made it in the first place.

>

> Third, the mainstream doctrine is not represented in this article,

> which is that the lactate produced by the muscles is used by the

> *liver.* Instead, this article asserts that it is used by the muscle,

> without presenting any evidence of such, and despite the fact that it

> doesn't make any sense.

>

> Finally, I do not know if it is true that lactate is toxic to muscle

> cells, but I don't see how this article presents evidence otherwise.

> I would be kind of surprised if a buildup of any acid was not toxic to

> a cell since it is, well, a buildup of acid. Also, Ray Peat says that

> a buildup of lactic acid in the blood carries adverse effects because

> it causes CO2 loss, which has a number of adverse effects, including

> decreasing oxygen delivery to tissues. I don't know how good the

> evidence is for this dynamic but it is an additional possibility to

> consider.

>

> Chris

>

[Guest guest]

Very curious. Yes, they probably mis-attributed it and the grave

illness was caused by something else - maybe the calcium ruptures

releasing too much calcium and causing problems?

I wonder what the vitamin C affects then to reduce muscle soreness.

Linus ing's theory was that it reduced the lactic acid, I

thought. But I know that it does indeed work to prevent sore

muscles. I just really overdid it shovelling snow a few weeks back

and had that fatigue and burning that usually mean I'll be sore the

next day. I took about 3 grams of vitamin C and the fatigue and

burning were gone and no symptoms of muscle fatigue/soreness the next

day at all.

> > >

> > > -

> > >

> > > > " Lactic acid is actually a fuel, not a caustic waste product.

> > Muscles

> > > > make it deliberately, producing it from glucose, and they

burn it

> > to

> > > > obtain energy. "

> > > >

> > > > Interesting eh?

> > >

> > > Yeah, my understanding is that the association of muscle

fatigue

> > with

> > > a buildup of lactic acid has turned out to basically be a

myth. A

> > > significant part of the problem actually involves the muscle

> > simply

> > > getting too hot to function properly, but there are other

issues

> > too,

> > > many of which we're probably not yet aware of.

> > >

> > > -

> > >

> > >

[Guest guest]

,

> Ya, well if low oxygen and lactic acid appear pretty much

> simultaneously, it would seem to me that the lactic acid is a backup

> system for energy production....

That's exactly what it is. But no energy is produced from the lactic

acid in the muscle cell; instead, energy is produced by the formation

of the lactic acid. Basically turning pyruvate into lactate allows

glycolysis to continue making pyruvate and thus producing a very tiny

amount of ATP, whereas without making the lactate, the whole entire

energy system would collapse. Even still, you are making 2 versus >30

ATP per glucose. The lactate is then exported and used by the heart

for energy or used by the liver for either energy or glycogen storage

or to make glucose to send back to the muscles, which can continue to

be inefficiently burned for these 2 ATP.

> in which case the lack of oxygen would

> also have a variety of other effects on the whole body...and you would

> just have to find the best way to increase oxygen to your cells...most

> likely through healthy diet and something like sprinting if I am

> thinking properly.

Right, also B vitamins and CoQ10 and various other things that allow

the O2 to be used.

> Many mechanisms seem still unknown, but its really hard to find the

> cause and effect in the statement Ray Peat said regarding lactic acid.

> Yes it may build up but isn't oxygen already low at that point in the

> muscles? It would seem that the lactic acid backup energy production

> would seem to further exacerbate the problem if that statement was

> true...but it doesn't explain why athletes seem to do better with less

> muscle cramps after drinking pickle brine with lactic acid...because

> that would also raise blood lactate levels right?

I don't think he's talking about exercise specifically, but

chronically. In either situation acid would push out CO2 because one

of the mechanisms of decreasing acidity in the blood is to get rid of

CO2, which is acidic. Still, acids as well as CO2 help O2 delivery,

so I'm not sure how it all balances out.

The lactic acid is an easy source of energy, that is probably the

mechanism, and it is easy for the liver to make into blood sugar. But

that does not mean that the lactic acid being produced by the muscle

is used by the muscle, as the article was saying, which does not make

sense.

Chris