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heart rate vs blood sugar



 
 
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  #1  
Old September 24th 03, 02:07 AM
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Default heart rate vs blood sugar

Hi, I've noticed that after about 30 minutes of heavy-hand exercise
at around a 13 MET level, my heart rate seems "magically" to go up
as much as 10 beats per minutes. That is, if I'm at 130 during
the first 30 minutes, staying at the same level of exercise yields
around 140, plus or minus, for the rest of the session. I've been
pondering what might cause this fairly consistent effect, and I've
come up with a theory I'd like to run up the flag pole.

BTW, has anyone else noticed this effect?

Anyway, I've had reduced calories & a low glycemic diet for a couple
of months, and I exercise before breakfast. Therefore (I presume)
I have relatively low glycogen stores. When I start exercising (I
theorize), a relatively large high percentage of my energy use is
fueled by what glycogen there is, but after 30 minutes, since the
levels will have fallen to a low rather level, a relatively greater
percentage of my energy use is fueled by fat.

Now, fat-burning requires more oxygen that glycogen-burning, so
since the energy use remains constant (I stay at the same level of
exercise), I have to take in more oxygen. Since at that level of
exercise, the pulse has fairly linear relation to oxygen use, my
pulse goes up. QED.

What do you think, could this theory account for the heart-rate boost?

There are implications, because I am using my heart rate to estimate
the oxygen use (and therefore MET level & calories) for my training
program, and I have to be careful to do the baselines twice, once
during the "glycogen dominant" phase of my workout, and once during
the "fat dominant" phase. It also means that in the 2nd phase, I
keep bumping up against my max heart rate, and therefore can't
maintain the same intensity as during the 1st phase.

Greg Shenaut
  #2  
Old September 24th 03, 05:38 AM
Denise Howard
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Default heart rate vs blood sugar

In article ,
wrote:

Hi, I've noticed that after about 30 minutes of heavy-hand exercise
at around a 13 MET level, my heart rate seems "magically" to go up
as much as 10 beats per minutes. That is, if I'm at 130 during
the first 30 minutes, staying at the same level of exercise yields
around 140, plus or minus, for the rest of the session. I've been
pondering what might cause this fairly consistent effect, and I've
come up with a theory I'd like to run up the flag pole.

BTW, has anyone else noticed this effect?

Anyway, I've had reduced calories & a low glycemic diet for a couple
of months, and I exercise before breakfast. Therefore (I presume)
I have relatively low glycogen stores. When I start exercising (I
theorize), a relatively large high percentage of my energy use is
fueled by what glycogen there is, but after 30 minutes, since the
levels will have fallen to a low rather level, a relatively greater
percentage of my energy use is fueled by fat.

Now, fat-burning requires more oxygen that glycogen-burning, so
since the energy use remains constant (I stay at the same level of
exercise), I have to take in more oxygen. Since at that level of
exercise, the pulse has fairly linear relation to oxygen use, my
pulse goes up. QED.

What do you think, could this theory account for the heart-rate boost?


The elevated heart rate after awhile at the same exertion level is a
normal response to prolonged exercise. As the muscles get fatigued,
additional muscle fibers are recruited to assist. More blood is
required, to deliver oxygen to not only the fatigued muscles but the
additionally-recruited fibers. The only way to deliver more oxygen at
that point is to breathe harder and beat faster, so that's what
happens. It has nothing to do with blood sugar or fat-burning.

--
Denise denise dot howard at attbi dot com
ACE and AFAA certified fitness instructor
AFAA step certified
  #3  
Old September 24th 03, 08:01 AM
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Default heart rate vs blood sugar

Denise Howard wrote (Wed, 24 Sep 2003 03:38:45 GMT):
The elevated heart rate after awhile at the same exertion level is a
normal response to prolonged exercise. As the muscles get fatigued,
additional muscle fibers are recruited to assist. More blood is
required, to deliver oxygen to not only the fatigued muscles but the
additionally-recruited fibers. The only way to deliver more oxygen at
that point is to breathe harder and beat faster, so that's what
happens. It has nothing to do with blood sugar or fat-burning.


Hmm, well for the sake of argument, why would more than a basal
level of oxygen be needed for the fatigued muscle fibers--if they
are fatigued, they aren't doing much work, right?. And, why don't
my muscles feel fatigued? Instead, at the point where the heart
rate picks up, I generally just feel loosened up & ready to go--it's
usually only 30 minutes or so into a 90 minute workout.

It seems to me that if the oxygen requirement per joule (or calorie)
remains constant, then it wouldn't matter how many or which muscle
fibers you are using, the energy consumption (and oxygen usage)
would remain the same if the energy expenditure remained constant,
and this is what your explanation would seem to predict. Under my
model, the fuel mixture switches from a source requiring relatively
little oxygen (more glycogen) to one requiring more oxygen (more
fat), and so at a constant energy expenditure, it would predict the
observed faster breathing & higher heart rate.

Greg
  #4  
Old September 24th 03, 02:27 PM
Isiafs5
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Default heart rate vs blood sugar



I've noticed that after about 30 minutes of heavy-hand exercise
at around a 13 MET level


What is MET?

my heart rate seems "magically" to go up
as much as 10 beats per minutes.
BTW, has anyone else noticed this effect?


It has been my experience that at a given rate of effort, my heart rate
eventually rises, also.

I do note that my body is heating while I exercise and wonder if the heart has
to somehow work harder to help cool the body.

I've had reduced calories & a low glycemic diet for a couple
of months, and I exercise before breakfast. Therefore (I presume)
I have relatively low glycogen stores.


Maybe, but from my experience with all the books, etc. that take one aspect of
our very complex systems...well, there at lots of factors at work. I have not
seen or read anything that overrides the total energy in versus energy out for
fat percentage.

I would suggest that the total volume of training is much more important of
glycogen storage. As your body adjusts to the demands it will automatically
start stealing more and more glycogen for storage and leaving less for fat
cells.



Sling Skate

My recommended reading for body fat control:
http://www.geocities.com/~slopitch/drsquat/fredzig.htm










  #5  
Old September 24th 03, 05:34 PM
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Default heart rate vs blood sugar

Isiafs5 wrote (24 Sep 2003 12:27:13 GMT):


I've noticed that after about 30 minutes of heavy-hand exercise
at around a 13 MET level


What is MET?

It is a measure of exercise intensity.

I've had reduced calories & a low glycemic diet for a couple
of months, and I exercise before breakfast. Therefore (I presume)
I have relatively low glycogen stores.


Maybe, but from my experience with all the books, etc. that take one
aspect of our very complex systems...well, there at lots of factors at
work. I have not seen or read anything that overrides the total energy
in versus energy out for fat percentage.


No, you don't understand my point. The energy expenditure is
remaining the same (that's the point of figuring out the METs of
the particular exercise), but it takes *more oxygen* to get energy
from fat than it does to get it from glycogen, so energy source
becomes one of the factors effecting heart rate.

Here's a not-so-great analogy: suppose you have a hybrid vehicle
with a main electric motor. It has a bank of batteries as its main
power source. However, there is also a secondary gas engine on
board. The gas engine is set to "kick in" when the output of the
battery bank falls below a certain threshold. Normally, it kicks
in rarely, but on a long drive, it would be used more and more of
the time. The work being done (driving down the highway at a fixed
speed) remains the same regardless of the percentage of time the
electric & gas systems are used.

Now, if we measure the *oxygen usage* of that vehicle while it is
on that long drive, it will start out very low, because very little
if any oxygen is needed by the batteries. However, as the gas
engine kicks in more and more, the oxygen usage will increase.

Similarly, as the glycogen store becomes depleted, the body is
required to dip into the fat store for fuel, and that increases
the oxygen demand, causing the heart rate to increase as it
distributes the oxygen around the body.

Greg









  #6  
Old September 25th 03, 06:04 AM
Denise Howard
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Default heart rate vs blood sugar

In article ,
wrote:

Denise Howard wrote (Wed, 24 Sep 2003 03:38:45 GMT):
The elevated heart rate after awhile at the same exertion level is a
normal response to prolonged exercise. As the muscles get fatigued,
additional muscle fibers are recruited to assist. More blood is
required, to deliver oxygen to not only the fatigued muscles but the
additionally-recruited fibers. The only way to deliver more oxygen at
that point is to breathe harder and beat faster, so that's what
happens. It has nothing to do with blood sugar or fat-burning.


Hmm, well for the sake of argument, why would more than a basal
level of oxygen be needed for the fatigued muscle fibers--if they
are fatigued, they aren't doing much work, right?.


Don't assume that because they are fatigued they "aren't doing much
work". They are definitely still working a lot, otherwise your heart
rate would go down as your workout progresses, not up. Muscles that
aren't working don't have a big oxygen demand.

And, why don't
my muscles feel fatigued? Instead, at the point where the heart
rate picks up, I generally just feel loosened up & ready to go--it's
usually only 30 minutes or so into a 90 minute workout.


You don't need to "feel" fatigued for muscle fibers to be fatigued.

It seems to me that if the oxygen requirement per joule (or calorie)
remains constant, then it wouldn't matter how many or which muscle
fibers you are using, the energy consumption (and oxygen usage)
would remain the same if the energy expenditure remained constant,
and this is what your explanation would seem to predict. Under my
model, the fuel mixture switches from a source requiring relatively
little oxygen (more glycogen) to one requiring more oxygen (more
fat), and so at a constant energy expenditure, it would predict the
observed faster breathing & higher heart rate.


It has been clinically shown that there are no "on/off" switches in the
body for "fat-burning" or any other metabolic pathway. The body's
energy systems operate on a continuum.

--
Denise denise dot howard at attbi dot com
ACE and AFAA certified fitness instructor
AFAA step certified
  #7  
Old September 25th 03, 04:18 PM
Peter Webb
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Default heart rate vs blood sugar


"Denise Howard" wrote in message
...
In article ,
wrote:

Denise Howard wrote (Wed, 24 Sep 2003 03:38:45

GMT):
The elevated heart rate after awhile at the same exertion level is a
normal response to prolonged exercise. As the muscles get fatigued,
additional muscle fibers are recruited to assist. More blood is
required, to deliver oxygen to not only the fatigued muscles but the
additionally-recruited fibers. The only way to deliver more oxygen at
that point is to breathe harder and beat faster, so that's what
happens. It has nothing to do with blood sugar or fat-burning.


Hmm, well for the sake of argument, why would more than a basal
level of oxygen be needed for the fatigued muscle fibers--if they
are fatigued, they aren't doing much work, right?.


Don't assume that because they are fatigued they "aren't doing much
work". They are definitely still working a lot, otherwise your heart
rate would go down as your workout progresses, not up. Muscles that
aren't working don't have a big oxygen demand.


The OP is using the term "work" in the technical sense, of production of
mechanical energy.

And aren't you contradicting yourself? "Muscles that aren't working don't
have a big oxygen demand". What are you saying - that the fatigued muscles
are still producing mechanical energy? If this is the case, why is their
oxygen usage higher than non-fatigued muscle? (The OP gives you a very
interesting reason why this may be the case). And what is the relevance of
fatigued muscle?


And, why don't
my muscles feel fatigued? Instead, at the point where the heart
rate picks up, I generally just feel loosened up & ready to go--it's
usually only 30 minutes or so into a 90 minute workout.


You don't need to "feel" fatigued for muscle fibers to be fatigued.

It seems to me that if the oxygen requirement per joule (or calorie)
remains constant, then it wouldn't matter how many or which muscle
fibers you are using, the energy consumption (and oxygen usage)
would remain the same if the energy expenditure remained constant,
and this is what your explanation would seem to predict. Under my
model, the fuel mixture switches from a source requiring relatively
little oxygen (more glycogen) to one requiring more oxygen (more
fat), and so at a constant energy expenditure, it would predict the
observed faster breathing & higher heart rate.


It has been clinically shown that there are no "on/off" switches in the
body for "fat-burning" or any other metabolic pathway. The body's
energy systems operate on a continuum.


I am sure the OP would agree. That is simply not his argument.

Indeed, as a physicist I find the OPs argument extremely interesting. He
points out that the mechanical energy output (the work) is constant, while
the pulse rate gradually increases. He hypothesises that the increased pulse
rate is due to an increased oxygen use (very plausible). The conclusion is
then inescapable that the reactions occuring in the body are gradually using
more oxygen per unit of work output. He observes that fat metabolism uses
more oxygen per unit of work than glycogen metabolism, and so proposes this
as the mechanism. If it is true that fat metabolism uses more oxygen per
Joule than glycogen metabolism, I'm sold.

If you have a more plausible mechanism which explains the difference in the
O2 consumption to power output ratio as you exercise, please post it!

BTW, the effect is somewhat different in me. It kicks in almost as soon as
my pulse rtae stabilises (5 minutes), and my rate of 90% MHR execise level
increases at about 1 bpm per minute. After 20 minutes I am so close to my
MHR that I have to wind back my exertion.

Peter Webb



  #8  
Old September 25th 03, 06:31 PM
Denise Howard
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Default heart rate vs blood sugar

In article , Peter Webb
wrote:

The OP is using the term "work" in the technical sense, of production of
mechanical energy.


Fine.

And aren't you contradicting yourself? "Muscles that aren't working don't
have a big oxygen demand". What are you saying - that the fatigued muscles
are still producing mechanical energy? If this is the case, why is their
oxygen usage higher than non-fatigued muscle?


No, that's not what I said. The fatigued muscle fibers _are_ still
producing mechanical energy--they don't stop. Their oxygen usage is
not higher than non-fatigued fibers. It's the recruitment of
_additional_ muscle fibers to assist the fatigued fibers, which drives
up the oxygen demand.

(The OP gives you a very
interesting reason why this may be the case). And what is the relevance of
fatigued muscle?


See above.

If you have a more plausible mechanism which explains the difference in the
O2 consumption to power output ratio as you exercise, please post it!


The points I wanted to make are that there is no "switching" action
from one energy system to another, and there's no relevance for blood
sugar as indicated in the thread title. The body operates on a
continuum. So there's no moment where suddenly you're "burning more
fat". Such an idea harks back to the old exercise myth that "you have
to exercise continuously for 20 minutes for the fat-burning to kick
in".

--
Denise denise dot howard at attbi dot com
ACE and AFAA certified fitness instructor
AFAA step certified
  #9  
Old September 25th 03, 06:48 PM
Mu_nstruck
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Default Denise Howard's Certifications Are ****e

On Thu, 25 Sep 2003 16:31:38 GMT, Denise Howard
wrote:

Denise denise dot howard at attbi dot com
ACE and AFAA certified fitness instructor
AFAA step certified


From the AFAA.com website:

"Certification. Individuals and businesses that claim certification
by AFAA were duly certified as of the date of first placement on
AFAA.com. AFAA cannot assure that such certifications have not
expired or otherwise terminated since that date. Users are urged to
satisfy themselves regarding the current status of AFAA certification
of all individuals and businesses claiming such certification."

***I could care less about whether someone's certification is up to
date since I hold this certification, and many, many others like it,
relatively valueless.

Certainly, the public "enjoys" initials behind names. MD, PhD,
EdD.....all certifications of some academic/educational acumen.
That's what the fitness industry counts on; that you, the client, will
make the assumption that initials determine competency or credibility.
That there has been similar educational requirements, personal
commitments of time. I mean, you ARE working with human beings on
their two most important issues in life - quality and longevity. Why
else would they use them?

But let's take a look behind the scenes on this one particular
"certification": the Aerobics and Fitness Association Of America.

"The Aerobics and Fitness Association of America (AFAA) are the
world's largest Fitness and TeleFitness© Educator. More than 145,000
fitness instructors from 73 countries around the world have been
awarded a certification since 1983. Each year more than 2,500
workshops are hosted by health clubs and studios across the nation.
The certification exams are administered through the National Fitness
Testing Council."

****So it's not an exclusive club, is it? Try a Advanced Google
Search on National Fitness Testing Council. Here's what you get.

http://makeashorterlink.com/?M21442B41

*****Nothing. Who is this mysterious NFTC? Who owns it? Who
certifies them? So I called the AFAA and asked. "We'll get back to
you on that" Gave them my email address and tele number five days
ago. No response.

You will find an interesting article written about the stupidity and
dangers of offering "one day workshops" for certifications as follows:

http://makeashorterlink.com/?Y14451B41

A short quote:

"How can we ask the public to put their trust and money into our clubs
when our certified professionals may not have the knowledge and
experience necessary to safely guide them through effective exercise
programs? It's not that one-day certification programs don't have a
place in our industry. Some of them are very good, but they are best
tailored to those with prior fitness instruction education and
experience who need additional training not the individual who has
decided to make a fitness career out of a one-day course. "

Back to getting our certification:

"Step Certification. Includes: study guide, one-day workshop, written
and practical exams. "

******I called up an AFAA trainer at one local gym and asked about the
study guide. "Oh, you mean the test answers?".

"Current CPR required before certificate is issued."

****The CPR makes for a good idea when your step/music director fails
to notice you're red in the face and completely out of
breath.......lying on the floor! Seen it more than once.

"Personal Trainer/Fitness Counselor Certification. Includes: study
guide, three-day course including lectures and practical
demonstrations, written and practical exams.
Prerequisites. Early registration and self-study before program.
Exercise Science Fundamentals home study is also recommended. Current
CPR required before certificate is issued.

***A whole three days for this one and now what. You can be certified
to make people "fit". But what is "fit". I looked all over the AFAA
website to determine their, hell ANY, definition of fitness but none
exists. But you can be certain your certified AFAA fitness trainer
can make you such. Remember, he/she is well trained.....for three
days with the test answers in hand!

I did find this, though.

"Personal trainers will be qualified to provide individuals with a
personalized fitness training program. "

They don't know what fitness is but, in three days (less than 24 hours
of "education"), you can write programs that determine the longevity
and health on millions of individuals and charge them exorbitant fees
of up to $100 per hour. Why can you do this?

BECAUSE YOU ARE CERTIFIED!!!!

Who Can Go For It?

"In order to register for courses it is suggested that you register
early and undertake a self-study period before the program. (See
comment on "study guide" above). Exercise Science Fundamentals home
study is also recommended (but not required). "

****Hmmm, no degrees, no prior experience, no arms, no nothing of
value except, of course, your registration and study guide fees!

"Trainers who earn this new certification will have increased
knowledge and resources, which is key to client retention."

***Oh, I get it. Put some initials behind your name so you can make
more money. Of course, the clubs whereabouts these "well- educated,
certified fitness pros" lurk will reimburse for these wonderful
initials, this valuable asset to customer service (and their profit
margins), right?

Wrong. I called the home office of LA Fitness, Gold's Gym and World
Gym and asked if they do, or recommend to their franchisees, that they
reimburse for these vital courses. All three answered "NO".

Recertification

The AFAA is no slouch when it comes to "fitness pro retention" either
since you are required to continue your education with them. How does
one do this?

HOME STUDY! TAKE THE TEST AT HOME !! NO PEEKING AT THE "STUDY GUIDE"
!!!

"AFAA's CEU Corner program is the best continuing education offer
available. And the online version gives you the convenience and
availability of TeleExerciseTM. Simply read the comprehensive article
(which rarely is over 500 words!) and pass the corresponding quiz to
earn two CEUs for a $20 fee. Successful completion of a CEU Corner
exam counts as the AFAA course required for recertification. "

*****Let's see, I need 15 CEU's to get recertified or $300. I get the
answers online and I promise not to cheat. IS THIS A DEAL OR WHAT?
We can get certified in as long as it takes to read a Spiderman comic
front to back!

Here is question #15 (of 15, btw)of the online quiz. It's a toughie
but maybe we can figure it out.......since the answer is just a BACK
button on my browser away (remember the 25 line article we read?):

Q. Qualified trainers are important for the following reason(s):

A. a) to educate people on the importance of strength training for
health.
b) to optimize the safety and design of a training program.
c) to provide competent guidance in the training process.
d)All of the above.

I don't know about you but.........I picked (d.) Gee, I hope I am
right ))))

So let's summarize the AFAA certification.

1. I takes money but very little brains.
2. You are certified, in a one - three day workshop, to become a
fitness pro, whatever the hell that might be.
3. You get initials. You are now credible.
4. Once you have made a workshop, run by another AFAA "fitness pro",
you can sit on your butt at home and answer stupid questions, which
you have the answers, to "up your education and get recertified).
5. Reading is not a prerequisite. The AFAA will allow someone else
to read the "articles" to you and let them send in the answers for
you.
6. You have to have several hundred dollars a year to keep your well
deserved certification but not much else.
7. I did say you get initials behind your name, didn't I?

And don't even get me started on the ACE (American Council of
Exercise) certification.

  #10  
Old September 25th 03, 09:46 PM
John
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Default Denise Howard's Certifications Are ****e

Mu_nstruck

wrote: (snipped)
So let's summarize the AFAA certification.

1. I takes money but very little brains.
2. You are certified, in a one - three day workshop, to become a
fitness pro, whatever the hell that might be.
3. You get initials. You are now credible.
4. Once you have made a workshop, run by another AFAA "fitness pro",
you can sit on your butt at home and answer stupid questions, which
you have the answers, to "up your education and get recertified).
5. Reading is not a prerequisite. The AFAA will allow someone else
to read the "articles" to you and let them send in the answers for
you.
6. You have to have several hundred dollars a year to keep your well
deserved certification but not much else.
7. I did say you get initials behind your name, didn't I?

And don't even get me started on the ACE (American Council of
Exercise) certification.



At least Denise posted her credentials for you to tear apart. What are yours?
Denise's posts in the past have been for the most part, well stated, correct
and seem to demonstrate a genuine desire to help.
It's easy to critisize a faulty system, what are your suggestions to correct
it. College degree? I've seen enough exercise physiologists that were well
versed in physiology, but had no place in a training environment. A physical
therapist would certainly be capable, but would charge much more that a
"certified trainer". IMO there is no substitution for experience. A trainer
could not afford to stay in business for 10 years if they were inept. Many
gyms require the certification to get a job...to get the necessary experience.

John


 




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