Posted on 11 Mar 2010 00:15
I'll just bet you answered a big YES to that. That is probably what you have been told. That it is a foregone conclusion that strength and bodybuilding trainees (and all chronic exercisers or athletes) should be hitting up the antioxidant supplements like they are water.
Well it's not a forgone conclusion. First of all "oxidative stress" is not a simple subject. And it's not just whether you should take antioxidants but if so, how you should take them.
First things first.
What is oxidative stress?
Oxidative stress is an imbalance between free radicals (pro-oxidant molecules) and the body's oxidative defense mechanisms. Primarily the free radicals in our bodies are derived from the consumption of oxygen but there are many possible radical species. The basic definition is a particle that contains one or more unpaired electrons and this can be true of many different substances. However the most important ones for us are those derived from oxygen or nitrogen. They are called reactive oxygen/nitrogen species or RONS for short.
How does the body deal with them?
The body has a basic antioxidant defense system composed of endogneous (produced by the body) and exognenous (coming from the diet) compounds. Examples of endogenous antioxidants are superoxide dismutases and glutathione peroxidase. You may have heard of those. In fact, glutathione is sold in supplement form by people who conveniently forget to tell you that glutathione is pretty worthless as a supplement since it is a tripeptide that does not cross the GI tract very well.
Exogenous antioxidants are the familiar nutrients like beta carotene (and other cartenoids), vitamin E and C, and various biflavonoids.
What does exercise have to do with it?
Well it's a very complex subject and scientists have a long way to go on it. But those that tell you "you must take antioxidants" misunderstand one key factor. There is a difference between the production of free radicals and oxidative stress. Yes, we know that acute exercise, both aerobic and anaerobic, results in radical species but that does not mean it automatically causes oxidative stress. Remember the definition of oxidative stress above. It is an imbalance between RONS production and the body's oxidative defense system.
The intensity and duration of the exercise, nutrition status, age, training status all seem to impact whether oxidative stress occurs. Higher intensity and duration of exercise tends to equate to more oxidative stress. But all the other factors have an impact as well and findings are inconsistent because of this as well as how the oxidative stress is measured. What tissue is looked at and when and what biomarker is chosen. It's not as cut and dry as your favorite bodybuilding guru told you, is it?
Ah, but the muscles…
Lifting them weights, commonly referred to as resistance exercise, is thought to cause an increase in free radical formation in the muscles. There are a couple of ideas as to how this occurs.
One is called the ischemia-reperfusion theory. When the muscles undergo an intense contraction there is a temporary decrease in blood supply and thus oxygen resulting in ischemia. As the muscles relax, they undergo reperfusion which means that blood and thus oxygen and nutrients rush back into them. The resulting inflammation and oxidative damage is sometimes called reperfusion_injury. Usually this theory is reserved for actual muscle injury but it is thought that reperfusion after intense contraction may give rise to an abundance of free radicals that damage muscle tissue.
The other theory is that mechanical stress being placed on the muscles physically damages them (high eccentric forces particularly) and that this causes and inflammatory process that produces free radicals.
Whatever the theory the common prescription is to take vitamin E, and C with special attention usually given to vitamin E. The idea should be clear enough. Your workouts produce free radicals that damage your muscle cells so lots of antioxidants should help protect them thus helping them recover faster.
Unfortunately there are few studies that actually test whether vitamin E actually reduces post resistance exercise lipid peroxidation in muscle tissue and there is not enough evidence to conclude that supplementation with E and C actually protects against this damage. As is usual with these types of things the results have been mixed and of course the protocols have as well.
Well shouldn't I take antioxidants just in case?
You should not take any supplements "just in case". There is a huge problem right now between the rationale for supplement use and the actual reason people take supplements with "just in case" being near the top of the list. It is not that clear how healthy long term supplementation with antioxidants is for you. And it is not really even that clear if they work as advertised.
Assuming that they work and that we should take them to reduce post exercise oxidative stress we must also assume that this stress is harmful. No, not all stress is ultimately harmful. Some stress is "adaptive". Good, or adaptive stress such as this is sometimes called eustress (as opposed to distress).
Exercise is a physical stress on the body but when done correctly it is a health producing stress not a health damaging one. Yes, it has been shown, at least to some extent, that exercise results in increased oxidative stress. But that does not mean that this is detrimental to health in the long term.
And remember what I said about training status? Well there is more and more evidence that when training results in oxidative stress this stress is hormetic. Hormesis is a phenomenom by which low doses of toxic substances produce favorable, and ultimately protective, responses. Eustress is really another name for this general idea.
Hormesis Dose Responses Graph
Hormesis Dose Responses Graph
In terms of healthful states, too much RONS production and not enough defense is termed an oxidizing environment. Conversely, a healthful state would be thought to be a reducing environment. And environment that favored the destruction of free radicals because of increased antioxidant defense.
It just so happens that regular moderate intensity exercise appears to do just that. We know that exercise makes us healthier. Well increased antioxidant defense may be one of the ways this happens.
Moderate Intensity? I'm Hardcore!
Chill out, tough guy. It's the median intensity we are talking about. Just because you go "all out" some of the time, or work at percentages of greater than 90 percent maximum load sometimes, etc. and so on, it does not mean you need to down a bottle of vitamin E after or before your next workout.
First of all intensity is relative to the individual and if you are able to work at insanely intense levels every time you exercise you probably don't exercise "regularly". And regularity is just as important as "intensity". It all evens out in the wash.
Most of the research concerning post exercise oxidative stress is examining acute exercise. In other words what happens as an immediate result of an exercise session. But the beneficial effects of exercise happen because of chronic exercise…exercise performed habitually over time at levels that can be sustained and recovered from. You'd need some really long term studies.
Exercise certainly seems to increase oxidative stress in untrained subjects but the problem is it has become simple dogma that the oxidative stress from exercise is bad thing that needs to be combated with pills. Are you seeing the dichotomy here? Exercise is good. Exercise makes you a patient in need of intervention to protect you from it's damaging effects. It doesn't make a lot of sense but there is still a debate going on. One side saying that antioxidant protection is needed to protect against these chronic effects and the other saying that but long-term exercise may counter the effect of oxidative stress by increasing the activity of antioxidant enzymes and reducing oxidant production. Leading to greater health than what you started with. You'll have to decide which side to put your money with.
Vitamin E or C?
Vitamin E is the supplement most frequently written about in bodybuilding articles because it is the main chain breaking antioxidant in lipid peroxidation. Since the cell walls are made of lipids vitamin E can help prevent oxidation of the lipids in cell walls and protect the stability and fluidity of the membrane.
However, vitamin C prevents lipid peroxidation in the fluid outside the cell walls and thus is equally important. What's more, the two work together. when vitamin E reacts to RONS it becomes a radical itself. Vitamin C is used to regenerate it. This produces a vitamin C radical which is reduced by glutathione. Ain't it rad?
So what should I do?
Read and research. Decide for yourself. I'll tell you what I do. I take a multivitamin and mineral supplement and that's about it. At times I take extra antioxidants in the form of vitamin E, C, beta carotene and some others but I don't believe it to be a make or break proposition and I doubt that I need it to protect myself from oxidative stress from my workouts. No, I don't believe that it has any impact on recovery.
The findings are all over the place but the most consistent results come from supplementation during or right after exercise rather than daily chronic ingestion over time, which takes high doses.
It is too early to say for sure just how valuable, or not, vitamin E and C are for exercise adaptation. For the untrained, the older, and those with inadequate antioxidant defense there may be more benefit. Vitamin C and E have NOT been shown to have any significant ergogenic effect but the actions may be subtle and all the endpoints have not been considered. Will it hurt you to pop some vitamin E and C after your workouts? I think not. Will it make or break you? I think not. How's that for a definite stance?
You don't need my opinion, though, and giving you my stamp of approval or a thumbs down is nothing more than an ego trip on my part. Instead, how about starting with Acute exercise and oxidative stress: a 30 year history. This article should be a perfect spring board to further research. Maybe you can come back and tell me a thing or two. See all the articles at GUS referencing oxidative stress.
- Groff, James L., and Sareen Annora Stepnick. Gropper. Advanced Nutrition and Human Metabolism. Belmont, CA: West/Wadsworth, 2000. Print.
- Fisher-Wellma, Kelsey, and Richard J. Bloomer. "| Full Text | Acute Exercise and Oxidative Stress: a 30 Year History." Dynamic Medicine. Biomed Central, 1 Aug. 2009. Web. 11 Mar. 2010. <http://www.dynamic-med.com/content/8/1/1>.
- Viitala, Peter, Et Al. E. "The Effects of Antioxidant Vitamin Supplementation on Resistance Exercise Induced Lipid Peroxidation in Trained and Untrained Participants." | Full Text | Lipids in Health and Disease (2004). Biomed Central, 14 Mar. 2004. Web. 10 Mar. 2010. <http://www.lipidworld.com/content/3/1/14>.
This page created 11 Mar 2010 00:15
Last updated 29 Jan 2017 00:53