TMBRA - Rider Board

 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Heart Rate 2 - A delve into the darker side

 
Post new topic   Reply to topic    TMBRA - Rider Board Forum Index -> Ask the Bike Doc
View previous topic :: View next topic  
Author Message
Anonymous
Guest





PostPosted: Wed Nov 10, 2004 3:03 pm GMT +0000    Post subject: Heart Rate 2 - A delve into the darker side Reply with quote

First of all I apologize about the subject heading but I just couldn't help myself.

Now for the issue at hand - has there been any studies that directly correlates HR to Lactic Acid Production, or do we just indicate that Lactic Acid Production usually takes place at a specific heart rate or HR range. I hope that does not sound too confusing. Let me know if this question needs further explaining on my part.

Next, if Lactic Acid Production is independent of HR does this mean that your Heart rate could be elevated due to the release of adrenaline (epinephrine) into the blood and that in turn you could get a high HR reading without producing Lactic Acid?

Doc, if you find any studies on this please paste a link or paste the relevant portion into the forum.

Thanks again for the free medical information
Back to top
The Bike Doc
250+


Joined: 08 May 2003
Posts: 1369
Location: Corpus Christi and Warda, Texas

PostPosted: Wed Nov 10, 2004 5:00 pm GMT +0000    Post subject: Reply with quote

Branham:

To answer your question succintly: Yes, there have been studies (BOOCOOS).

Here are just a few:

http://www.biomed.cas.cz/physiolres/pdf/2004/53_45.pdf

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12439087

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12391432

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12070627

Go to PubMed http://www.ncbi.nlm.nih.gov/entrez/query.fcgi and do your own search under lactate threshold AND heart rate. Use the Limit section to get studies in English only and on Human subjects only.

It's late and I am way behind on my studies, so your home work assignment is to do some reviewing of these articles and report back on your new found knowledge.

Thanks,
_________________
Paul K. Nolan, MD
AKA: The Bike Doc
Back to top
View user's profile Send private message Visit poster's website
Anonymous
Guest





PostPosted: Wed Nov 10, 2004 8:35 pm GMT +0000    Post subject: Reply with quote

Man you have to be a Doc to read some of that stuff - am working on deciphering it but I must warn you I don't have and MD!
Back to top
Spencycles
Guest





PostPosted: Tue Nov 16, 2004 9:32 am GMT +0000    Post subject: Heart Rate and Lactic Acid Reply with quote

BBranham,

I will take a shot at clarifying the relationship between HR and lactic acid production. To really understand it, you do have to delve into the physiology jargaon, but I will try to translate and simplify as best as possible.

The first thing to understand is that anytime you exercise, you are producing lactic acid. It is a product of the process to turn carbohydrate into energy. At lower intensities, the lactic acid is taken into the mitochondria of the muscle cell, broken down further, and used to produce substantially more energy. At high intensities (above Lactate Threshold), lactic acid is produced more rapidly than it can be absorbed into the mitochondria, so it accumulates in the muscle, causing the all familiar burn.

Now as far as how this relates to heart rate. As your workload (power output) increases, all of the physiological indicators increase. The ones that are usually measured include heart rate, lactic acid production (accumulation in blood), power output, oxygen consumption (VO2), ventilatory rate, and other more technical measures. In a controlled environment all of these indicators increase proportionately to each other. As one (power output) increases they all increase.

So when you go for performance/VO2 testing, they measure all of these things and identify your lactate threshold (LT) or workload at which lactic acid accumulates faster than it can be absorbed into the mitochondria. Once the threshold is identified, they simply look at your other values at that point to define your LT Heart Rate, Power at LT, VO2 at Threshold, etc.

Notice above that I specified this clean process exists in a controlled environment. Other factors can effect these indicators, specially heart rate. The usual culprits are nerves, adrenalin, fatigue, high air tempertaures, illness.

That is greatly simplified, but as clear as I can word it without going into the dark world of exercise phys. jargon.

I hope this is helpful,

Brett Spencer
USA Cycling Licensed Coach
www.Spencycles.com
Back to top
Anonymous
Guest





PostPosted: Tue Nov 16, 2004 9:40 am GMT +0000    Post subject: Reply with quote

Spencycles,

Ok I think I am following so - When Adrenaline is released and thus increase your HR does this also increase Lactic Acid production? Or does it increase your HR thus moving your HR at LT up.

This is where I am heading. I realize that when I race I have adrenaline, also my HR is much higher than I train at (even at extended times). I am just trying to figire out this relationship.
Back to top
The Bike Doc
250+


Joined: 08 May 2003
Posts: 1369
Location: Corpus Christi and Warda, Texas

PostPosted: Tue Nov 16, 2004 11:24 am GMT +0000    Post subject: Reply with quote

BBranham:

Epinephrine allows the body to increase glucose production which enables more glucose based energy to be used by muscles during the fight or flight response. When there is adequate glycogen stores lactate production is lower, however when glycogen stores are depleted lactate production is increased (see article: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9831734 ). So depending on your state of glycogen epinephrine can decrease lactate production or may increase it. There are some other interesting articles on epinephrine and lactate at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=723509 and http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2985381

Hopefully this won't confuse you more.

Thanks,
_________________
Paul K. Nolan, MD
AKA: The Bike Doc
Back to top
View user's profile Send private message Visit poster's website
Spencycles
Guest





PostPosted: Tue Nov 16, 2004 11:25 am GMT +0000    Post subject: HR and Lactic Acid Reply with quote

Adrenaline and other hormones will increase your HR, but not your lactic acid production/accumulation. The only thing that will cause you to accumulate more lactic acid is an increase in your actual workload.

If you ride at a certain workload in a non-competition workout, and the same workload in a race, your heart rate in the race will tend to be slightly higher, due to adrenaline, anxiety, and the other factors unique to race day.

An interesting note on this subject: When you train, one of the changes you bring about over time is an increase in the number of mitochondria in the muscle cells. The more mitochondria you have the more lactic acid you can absorb and the more energy you can produce. So this effect of training lets you more efficiently use carbohydrate and allows you to delay the accumulation of lactic acid and the burn that goes along with it.

Brett Spencer
USA Cycling Licensed Coach
www.Spencycles.com
Back to top
Display posts from previous:   
Post new topic   Reply to topic    TMBRA - Rider Board Forum Index -> Ask the Bike Doc All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group