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>> > ..2..The enlargement is not a consequence of
>> aerobics; the slower heartbeat or
>> > pulse rate reflects greater efficiency
>
>The heart's weight, volume, and left ventricle's
>thickness and chamber size all increase as a result of
>endurance training.

When i was a semi professional soccer player , we did a special training
before the season started.
We did endurance running ( slow pace but long time) for 3 weeks we got told
that our heart volume will increase and the walls wil get thinner
proportionally to the volume. The result was that i could play 3 games in a
row without any tiredness , but was totally unable to accelerate the pace, i
could not sprint anymore.
Following that endurance training and to complete it we did 3 weeks of
resistance training ( soudain short accelerations followed by walking) and
we got told that now the walls of the heart will become thicker and will
allow the heart to circulate the blood with more force.
Once we completed the process , it was amazing how much i gained on races
like 400 m or 800.m or evn 1500 m  ( races that i was not very good at,
being too endurant in the 1st place) i never felt as powerfull at that time.
2 years later i quitted all sports ( i was studying to be a sport teacher)
went thru emotionals trauma
made big change in my lifes) and had very little physical activities except
gardenning the 2nd year and none the 1st year . 2 years more and i got very
sick ( in fact my health started to
decline when i quitted,  to reach the point of total unability of movments)
i
always understood that it was a big factor in my health decline ( at the
same time i became vegetarian with cooked grains and dairies and raw
vegetables)
So was it the quitting that damage my health or was it the intensity of the
training ( 3 hours everyday)?
I wonder if a high intake of carbohydrate ask for more physical activities,
specially the aerobics ones to counterbalance and make it okay  but without
exercices it is a dangerous diet .
jean-claude


Cardiac muscle hypertrophies just
>like skeletal muscle as a result of endurance
>training.  At one time the this enlarged heart
>condidtion known as "athlete's heart" was a cause for
>concern because previous research indicated a
>pathological state for increase in heart size.
>
>The increase in left ventricle wall thickness and
>contractility is a result of a higher blood plasma
>volume due to endurance training.  This leads to a
>larger filling of the left ventricle.  A larger
>preload and end diastolic volume.
>
>When comparing bodybuilders and endurance athletes,
>the relative size of the heart and left ventricle is
>larger in endurance trained individuals.(Milliken et
>al.)
>
>As a result of endurance training, Stroke volume(SV)
>increases.(A greater filling of the LV and more
>forcefull contraction)  A greater end diastolic volume
>means more blood enters the left ventricle.  A greater
>end systolic volume means more blood leaves the left
>ventricle after contraction.  This is why enduracne
>athletes typically have low blood pressure.
>
>Moving on to heart rate.  Endurance training decreases
>resting heart rate.  Period.  The actual mechanism is
>not known but it works.  The gentleman whose tumors
>are shinking might not know how it is happening, but
>it is presumable due to paleo eating.
>
>A-VO2 Differnce.  In response to endurance training,
>the arterial O2 changes very little, but the Venous O2
>has less O2 due to a greater O2 extracton at the
>tissue level and more efficient distribution of blood
>volume
>
>One final note.
>VO2 = SV x HR x a-vO2 difference.
>At maximum exercise levels, an increase in SV and
>increase in a-vO2 differnce leads to an increase in
>VO2
>
>Endurance training affects VO2
>
>Wilmore and Costill. "Physiology of Sport and
>Exercise"  Human Kinetics. 1994
>
>
>>
>> Yes, but what makes the heart more efficient?  It
>> has been a long
>> time since I read about this stuff, but what I
>> recall is that the
>> increased efficiency is mainly the result of greater
>> stroke
>> volume.  This is the result of enlargement, in
>> highly aerobically
>> trained individuals.
>>
>> >   But the size of a heart is not an indicator of
>> its health. >>
>> >
>> > .3...an enlarged heart is not a sign of health but
>> a sign of disease.
>>
>> Is that categorically true?  I'll have to do some
>> digging, but
>> I'm pretty sure that enlargement is not unusual in
>> people who do
>> a lot of aerobics, and not pathological either.
>> When it occurs
>> in untrained people, that's something else again.
>>
>> Todd Moody
>> [log in to unmask]
>>
>
>=====
>-kb.
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