Taken from his weekly newsletter; for those that don't get it, sign up. Gomez-Cabrera MC et. al. Oxidative stress in marathon runners: interest of antioxidant supplementation. Br J Nutr. (2006) Suppl 1:S31-3. We have recently reported that xanthine oxidase is involved in the generation of free radicals in exhaustive exercise. Allopurinol, an inhibitor of xanthine oxidase, prevents it. The aim of the present work was to elucidate the role of exercise-derived reactive oxygen species in the cell signalling pathways involved in the adaptation to exercise in man. We have found that exercise causes an increase in the activity of plasma xanthine oxidase and an activation of NF-kappaB in peripheral blood lymphocytes after marathon running. This activation is dependent on free radical formation in exercise: treatment with allopurinol completely prevents it. In animal models, we previously showed that NF-kappaB activation induced by exhaustive physical exercise leads to an increase in the expression of superoxide dismutase, an enzyme involved in antioxidant defence. We report evidence in man that reactive oxygen species act as signals in exercise as decreasing their formation prevents activation of important signalling pathways which can cause useful adaptations in cells. My comments: This is what happens when Pubcrawler is lame in a given week, I have to dredge out something like this. Ok, I'm being melodramatic, this is actually a topic I've been following for a while of late: the potential issue that anti-oxidant supplementation might be detrimental to certain aspects of exercise adaptation; in this case, endurance performance. Back in the early days of both sports nutrition and longevity research (for example Colgan's "Optimum Sports Nutrition" and "Life Extension: A Scientific Approach" by Durk Pearson and Sandy Shaw), an idea that came up rather rapidly was that oxidative damage (due to the generation of free radicals, or what are now called reactive oxygen species or ROS) were a bad thing. Colgan had a list of anti-oxidant recommendations for hard training athletes and it was taken as an article of faith by the life-extensionists that a. oxidant damage was part of the aging process b. high dose anti-oxidant supplementation would limit said damage (and hence the aging process). I'm going to focus on 'a' here since I haven't looked into 'b' enough to say very much (except to say that many studies are finding that diets high in anti-oxidants do very different things than supplementing individual anti-oxidants). We know that exercise, and I'm going to focus on endurance exercise here, increases free radical production (if for no other reason than the increased utilization of oxygen) and there is some logic to the idea that taking supplemental anti-oxidants (either habitually or right around training) might limit damage. However, this neglects the fact that ROS appear to be part of the overall signalling pathways to adapt to training (it's also known that regular training tends to bump up the body's inherent anti-oxidant defense system). Over the last few years a number of studies have suggested that blocking the normal ROS response to endurance training might limit adaptations. For example, a very recent study (Close GL et. al.) found that vitamin C supplementation (1 gram 2 hours before and after downhill running) not only had no impact on muscle soreness but delayed recovery by limiting the production of ROS. Mechanistically this is similar to data showing that anti-inflammatories taken before training may limit growth by decreasing the normal inflammatory response to training. And, in hindsight, makes a certain sort of sense. Given the adaptations that occur in response to endurance training, it makes some logical sense that the production of ROS might actually be part of the signalling pathway. Blocking that response might attenuate the response seen to training. Which is a long way around of explaining the study above which basically says exactly what I wrote: exercise increases ROS, ROS are involved in the overall adaptation/signalling to endurance exercise, preventing their production with anti-oxidant supplements might serve to limit the adaptations to training. From a practical standpoint, based on the limited research, while I wouldn't use this to argue that no anti-oxidants should be taken or that an anti-oxidant rich diet, containing plenty of fibrous veggies and fruits should be avoided. But it looks like avoiding high dose anti-oxidant supplementation right around training might be a good idea from the standpoint of making sure that optimal adaptations occur. Interesting article. I've slightly adjusted my supplemental (I think that's key here) antioxidant intake; basically, avoiding any pre or post workout. It does make one wonder what it optimal, and what is potentially counter-productive to recovery.
I just skimmed over it, but he's talking about endurance exercise. Usually when Lyle refers to "endurance weenies" he really means endurance athletes and long distance type trainees. How this would impact strength training or weight lifting isn't covered necessarily in the article. Thanks for posting it though. I really like Lyle's stuff.
True, but one can assume 1 hour of steady state cardio versus 1 hour of resistance training, or god forbid, 1 hour of HIIT, would equal the same amount of oxidative damage. But that's a massive assumption. Hopefully, more light will be shed on this in the coming years.
