From: ekp@mcnc.org (Edward Pavelchek)
Newsgroups: misc.fitness
Subject: Re: Fitness thoughts
Date: 3 Sep 92 18:53:29 GMT
Article-I.D.: mcnc.1992Sep3.185329.22746
Organization: Good place for a disclaimer

In article <1992Sep2.151100.28230@inmet.camb.inmet.com> mazur@inmet.camb.inmet.com (Beth Mazur) writes:
>In article <1992Sep1.185619.21142@mcnc.org> ekp@mcnc.org (Edward Pavelchek) writes:
In article <1992Sep2.151100.28230@inmet.camb.inmet.com> mazur@inmet.camb.inmet.com (Beth Mazur) writes:
>In article <1992Sep1.185619.21142@mcnc.org> ekp@mcnc.org (Edward Pavelchek) writes:
>>
>Again, depends on whether one is trying to "get fit" or "lose weight."

Your bias jumps in here, as opposed to mine.  I was replying to 'fit'. 
(see below)
>>>Ed, are you disagreeing with the overall thesis -- that unfit people getting
>>>fit should generally stay below the anerobic threshold? 

>From T-Factor (p. 208):
>	Continuous whole-body movements are fat-burning activities.  They
>	will burn between 50 and 60 percent fat in the fuel mixture and
>	40 to 50 percent carbohydrate."

To get 60% fat burning from exercise seems to require either long
exercise times, a high fat diet, or drugs.  In 1939 (Christensen, Skand
Arch Physiol 81:160) a single well trained subject on his normal mixed
diet got 53% of energy from fat in the second half hour on a bicylcle.
After 3 days on a high carb diet, only 35% from fat in a repeat
exercise.  Then they put him on a no carb diet.  Over 90% came from
fat.  This of course suggests that those on a low fat diet will tend to
conserve fat during exercise.

>From Fit or Fat (p. 55-57):  [ this one's for Ed, Harry, and Phil :-) ]

[He's a little cute with enzymes.  They don't need O2 to work, O2 needs
them to work, from my point of view.  O2 does the work]
>	...[A heart rate between 65-80% is] able to supply enough oxygen
>	to the muscles so that glucose is disassembled through both
>	stages and completely burned.  [If > than 80%, ] the heart
>	and lungs cannot keep up with the oxygen demand in the muscle.
>	When this happens, the glucose will only break down to pyruvic
>	acid; there will not be enough oxygen to continue through the
>	second stage.  Since pyruvic acid cannot be burned ... it 
>	accumulates in the muscle and is converted into lactic acid...
>	When you stop and "catch your breath", oxygen flows into the
>	deprived muscle.  Most of the lactic acid turns back into
>	pyruvic acid.

Up to here, Bailey is ~fine.  His heart rate #s are guidelines only,
but they don't seem that way in this extract.  The insertion of 'all'
as in "Since all the pyruvic acid cannot be burned"  would clarify.
The fate of lactate is pretty complex.  Brooks is making his career on
it.  But O2 flows into the muscles all the time, not when you stop.

>	...Unlike glucose burning, ... all the enzymes used in fat
>	breakdown need a lot of oxygen.  Anaerobic exercise, therefore,
>	effectively shuts off all fat burning and forces the muscles to
>	use glucose exclusively."

All the enzymes used in pyruvate require O2, as the fat cycle.
His 'therefore' is misplaced.  

As a slow typist, I've become a little casual about complete
references.  This is what I've been reading.  I strongly recommend
Astrand if you can find him, and share my tastes.  After that Brooks or
McArdle.

_Exercise Physiology_ Brooks,G 1985
_Exercise Physiology_ McArdle  1985
_Exercise Physiology_ Stegemann,J 1981
Textbook of Work Physiology; Astrand  1986
Sports Medicine, 3rd edition 1988   Appenzeller
Scientific Basis of Athletic Conditioning; Fisher 1990
Training for Sport and Activity; Wilmore 1988
Physiology of Exercise, deVries 1986
Biochemistry; Lehninger  1975
Review of Medical Physiology; Ganong 1973



-- 
Ed Pavelchek   ekp@mcnc.org
But I make a profit of 3 1/4 cents an egg by selling them for 4 1/4
cents an egg to the people in Malta I buy them from for 7 cents an egg.
Of course, *I* don't make the profit.          Joseph Heller, Catcha 22