A glass of red wine is worth an hour of exercise. Red wine compound resveratrol may negate health benefits of exercise. Or both. Or neither.

Once again we have dueling headlines about the effects of red wine and resveratrol: Does it enhance the effects of exercise or negate them? A study from the University of Alberta in Canada found that resveratrol supplementation in animals improved muscle and heart functions in the same way as an hour of exercise would, leading the study’s lead author Jason Dyck to postulate that “We could conceivably create an improved exercise performance in a pill." Supplement marketers already label resveratrol as an “exercise mimic,” while bloggers and wine lovers conclude that a glass of red wine would therefore do the same.

Meanwhile, at Queen’s University a few provinces over in Ontario, researchers were finding that resveratrol supplementation blunted the benefits of high-intensity interval exercise, a seemingly opposite effect. In a four-week placebo-controlled clinical trial, the data “clearly demonstrates that RSV supplementation doesn't augment training, but may impair the affect it has on the body" according to the authors.

The implications from these studies are not so opposite as they may seem, however. For one thing, the study that found resveratrol enhanced exercise results was in animals, not a human clinical trial, and animal studies frequently do not produce the same results as clinical trials. Another key difference is that the clinical study was measuring whether resveratrol could enhance the effects of intensive exercise, while the animal study was looking at whether it could replace exercise. And all studies on resveratrol are potentially confounded by the fact that it may have completely different and even opposing effects at different doses, a phenomenon known as hormesis. For all of these reasons we are still a ways off from knowing the answer to the question of resveratrol as an exercise mimic.

One thing we can say (again) is that a glass of red wine is not the same as a resveratrol pill. The doses are different, and wine has a multitude of compounds that may interact synergistically with the small amount of resveratrol in wine. Wine drinkers are healthier in part because they tend to have healthier lifestyles including regular exercise.