Should you take antioxidants after a workout? This is something I thought I should write about after seeing an advert for a post workout protein powder with turmeric extract. While antioxidant supplements such as turmeric are extremely beneficial in most circumstances, I have always accepted that taking them after a workout is bad, because the “stress” of the workout is good, and results in a hormetic response (stress that allows your body to adapt and grow stronger), but antioxidants effectively cancel this out. It makes logical sense, but I never really dived into the research until now, and it seems that studies do support this.
For example high dose vitamin C and E after a strength training workout blunted the cellular response to the workout, particularly substances that initiate protein synthesis. Vitamins C and E also were showed to reduce the natural increase in insulin sensitivity after exercise. It seems that the production of ROS (reactive oxygen species) after exercise stimulate adaptive responses in endogenous antioxidant capacity and insulin sensitivity, as well as signalling cells to pump out proteins needed for strength and growth, and this tends to be blocked by exogenous antioxidants (i.e those made outside the body). In effect, this means exercise causes stress which produces positive adaptations in the body, so if you blunt this natural stress response with high dose antioxidants, you might reduce the benefits.
People often take antioxidants to reduce muscle soreness and enhance recovery but the studies are mixed on this. For example One small study used 400mg curcumin, but found that muscle soreness was not reduced while inflammatory cytokine production was blunted for a few days post workout, while other studies show the opposite (no significant change in inflammatory markers but reduced soreness).
In addition, taking antioxidants straight after a workout seems to reduce muscle hypertrophy in rats and in elderly humans but the author of Perfect health diet wrote an interesting take on antioxidants post workout, where he argues that less muscle size increase post workout is actually a GOOD thing as huge muscles are deleterious in the same way a big heart is. I can’t quite summarize it here, but it’s an interesting read.
It should be of note that many of these studies use very high dose single compound antioxidants (e.g one or two specific vitamins), so perhaps effects wouldn’t be seen with lower dose more broad spectrum antioxidants (for example eating a cup of blueberries after a workout).
In summary, it looks like the best thing to do is probably wait a few hours after exercise to take antioxidant supplements, and try to avoid super high doses of isolated antioxidants unless you do a really intense workout, where the damage and stress is beyond that needed for hormesis, or where you need to try and limit DOMS (delayed onset muscle soreness) for a particular reason.