Lactic Acid = Muscle Fuel, not Foe

[sydney_b]

Maybe you all have already read this, but it's a short article on what lactic acid really is. Apparently, research shows that lactic acid is fuel for your muscles, not the negative build-up that you sometimes read about. It's used by mitochondria, which are increased by hard training. W/o adequate training, there are not enough mitochondria to make use of the lactic acid and it's wasted. Check it out, much better said in the article.

NYTimes
http://www.nytimes.com/2006/05/16/health/nutrition/16run.html
(requires free registration)

[susiej]

You beat me to it!

But here's a no-reg version:

http://www.nytimes.com/2006/05/16/health/nutrition/16run.html?ex=1305432000&en=2778e99d7eab85a6&ei=5090&partner=rssuserland&emc=rss

And they confirm all the training advice on TE!

[Nanci]

(The writer, Karl King, _is_ a biochemist).

Well, the article was interesting but clearly written by someone who is not
a biochemist.

The biochemistry of shuttling lactate back into fuel has been known for a
long time. It's not like it was discovered yesterday.

What the article doesn't discuss at all is the aspect of acid accumulation
in the muscles when lactic acid is produced. "Combustion" of carbohydrate
leads to the production of acid, and it is the acid part of lactic acid that
causes problems. Lactic acid = acid ( hydrogen ion ) + lactate ion.

The lactate can be used for fuel, but the hydrogen ions have to be
neutralized or muscle damage results. When hydrogen ions accumulate, the
activity of muscle enzymes is degraded and the muscle becomes compromised.
If all the carbohydrate stored in muscles was immediately converted to
lactic acid, the resulting acid generation would be enough to kill the
muscle fibers. The slowing down as acid accumulates is just a protective
mechanism to make sure that you can't do permanent damage to the muscle
fibers by running at breakneck speed for a long time.

Should we consume lactate for fuel? Not really. Carbohydrate can be
processed more efficiently than lactate, so go for the carbs if you want to
run fast. Training at fast pace helps the body adapt to using lactate, and
buffering the acids produced during carbohydrate metabolism, so training
fast is indispensable for those who want to run fast. Owen Anderson of
Running Research News wrote a book that is a useful examination of training
at lactate threshold for runners ( NFI ).

Karl King
www.succeedscaps.com

[sydney_b]

Thank you for posting this added detail, Nanci. A lot of science news in the press is inadequately explained.

/s

[Bike Goddess]

Isn't it nice to have a scientist amongst us! Such talent here on the TE!:p :p :p :p :p

[margo49]

Weelll...that explains mitochondria too (helluva long word which I remembered dimly from the Science lessons of the 4th form (8th grade))

That Dr Brooks must have been some genius... I mean what can you really conclude from a dead frog (or half a one) about why it won't move even when you run electric shocks thru it?

Well done the other guy. Makes perfect sense. Isn't biology wonderful and the more you understand the more wonderful the body feels