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Caffeine and bloodflow to the heart

 
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PostPosted: Tue Jun 20, 2006 10:50 am GMT +0000    Post subject: Caffeine and bloodflow to the heart Reply with quote

I was reading in Bicycling(July 2006) that a Swiss study found caffeine decreases bloodflow to the heart during exercise by up to 39% by inhibiting the coronary arteries from expanding during exercise -- 2 cups(200mg) an hour before.

Any more info/thoughts on this?
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The Bike Doc
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Location: Corpus Christi and Warda, Texas

PostPosted: Wed Jun 21, 2006 6:40 am GMT +0000    Post subject: Reply with quote

wumpus:

That was interesting study that is summarized at:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16412869&query_hl=2&itool=pubmed_docsum

There are other reports with similar findings:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15674743&query_hl=2&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15136619&query_hl=2&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=7472591&query_hl=2&itool=pubmed_docsum

What was interesting about the Swiss study was that exercise was used to assess the caffeine effects on the heart, whereas, in the other studies, pharmacological maneuvers were used to simulate exercise.

There have been other studies that have shown caffeine may increase endurance:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16286872&query_hl=10&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16081625&query_hl=10&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15773860&query_hl=10&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15831802&query_hl=10&itool=pubmed_docsum

Keep in mind the studies on coronary blood flow were done on normal, young healthy individuals who likely have good coronary blood flow reserves, meaning the individuals had some buffer protection from the undesirable effects on the heart. They were not done on individuals with coronary artery disease. It is strongly recommended by cardiologist that patients with heart disease avoid caffeine due to the known undesirable effects blood flow to the heart. So what is my personal take? (My apologies to all you caffeineholics!) Caffeine IS a performance enhancing drug. Even though it is a natural occurring substance, it is still a drug (just like many other natural occurring substances that are used as drugs). Previously it was banned, when used in excess, by the World Anti-Doping Agency, but it was removed from the banned list but now is again being considered for the banned list. Though it can improve endurance by improving carbohydrate metabolism, it can have undesirable effects on the heart, even when used in moderation.

(Let the maelstrom begin! Mad )

Thanks,

TMT 8 DAYS!
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Anonymous
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PostPosted: Fri Sep 01, 2006 8:58 am GMT +0000    Post subject: Reply with quote

ok. maelstrom away ha ha!

I drink maybe between 12 and 24 diet colas a day. I always swill this nectar for my brain--somewhere along the line I lose track.

The main thing I've always wondered is --does so much diet cola inhibit weight loss? I think in Iraq the diet coke that was bottled in Jordon had a different artificial sweetener in it as it was tastier than the USA recipe and I seemed to lose weight readily----maybe it was the pesticides we're hearing so much about lately Shocked ??!!
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PostPosted: Thu Mar 08, 2007 10:00 am GMT +0000    Post subject: Reply with quote

Well now that Amgen/EPO sponsor the Tour of California, I guess that means we will see the Starbucks Tour of Washington or something.

They can't ban Espresso.
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