Antioxidants not good for vasodilation?

[Sleepstream]

Exercise-induced brachial artery vasodilation: The role of free radicals.

* Richardson RS,
* Donato AJ,
* Uberoi A,
* Wray DW,
* Lawrenson L,
* Nishiyama SK,
* Bailey DM.

Department of Medicine, UC San Diego, La Jolla, California, United States.

Originally thought of as simply damaging or toxic "accidents" of in vivo chemistry, free radicals are becoming increasingly recognized as redox signalling molecules implicit in cellular homeostasis. Indeed at the vascular level it is plausible that oxidative stress plays a regulatory role in normal vascular function. Using electron paramagnetic resonance (EPR) spectroscopy, we sought to document the ability of an oral antioxidant cocktail (Vitamins C, E and alpha-lipoic acid) to reduce circulating free radicals and employed Doppler ultrasound to examine the consequence of an anti-oxidant mediated reduction in oxidative stress on exercise-induced vasodilation. A total of 25 young (18-31 yrs) healthy male subjects partook in these studies. EPR spectroscopy revealed a reduction in circulating free radicals following antioxidant administration at rest (~98%) and as a consequence of exercise (~85%). Plasma total antioxidant capacity and Vitamin C both increased following the ingestion of the antioxidant cocktail, while Vitamin E levels were not influenced by the ingestion of the antioxidants. Brachial artery vasodilation during sub-maximal forearm handgrip exercise was greater with the placebo (7.4 +/- 1.8 %) than with the antioxidant cocktail (2.3 +/- 0.7 %). These data document the efficacy of an oral antioxidant cocktail in reducing free radicals and suggest that in a healthy state the aggressive disruption of the delicate balance between pro and antioxidant forces, can negatively impact vascular function. These findings implicate an exercise-induced reliance upon pro-oxidant stimulated vasodilation thereby revealing an important and positive vascular role for free radicals.

http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum

Does this mean that we should stop taking antioxidants post-workout in order to keep vascular function optimal after exercise?

[FlyingV]

Originally Posted by Sleepstream

http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum

Does this mean that we should stop taking antioxidants post-workout in order to keep vascular function optimal after exercise?

Not to me it doesn't. But taken at face value it suggests the trade off is between protection against exercise induced free radicals and prolonging the pump a little longer. I guess it comes down to which you value more.

And not to nitpick, but why do the study authors, I wonder, use the terms vasodilation and vascular function interchangably. One is very specific the other is very general - as vascular function incorporates way more than just dilation.

[5Six]

V is right. Them saying vascular function leaves a huge open ended statement.

But for me it seems that they didn't really prove anything major or revoultionary. Yes, we already know that exercise causes free radicals. We also know that the role of anti-oxidants decreasing free radicals. So combinging the two seems failry obvious. But I guess you need a study to prove the obvious sometimes.

Personally, I wouldn't worry much 'bout it. Just keep doing what you doing if it is working out for and it is causing no negative effects.