A couple of weeks ago I subbed a class for one of the morning instructors – it was the long weekend and I think he went up north on Thursday evening after work. Since I don’t normally teach at that time of day, my head wasn’t on just right. In my attempt to motivate them I made the following comment “that pain in your legs is lactic acid and it can’t hurt you.”
I’m not sure how effective the comment was at motivating the participants to keep working through the pain but it sure did stick with me for a while after. It turns out, that while my comment wasn’t inaccurate, it did contain some misleading information.
This study is a final installment by the group from New Mexico and it’s a doozy. I’ll start at the end. The conclusion that will soon hit some truly premier biochemistry journals is that lactate is a good guy, not a bad guy. It isn’t responsible for your burning quads on the twelfth rep of quad extensions. It sure as heck isn’t the reason for delayed-onset muscle soreness (for those few who might still think that).
I personally liken it to an innocent bystander at the scene of the crime. Here the crime is “metabolic shutdown” due to acidosis in an intensely working muscle. You see, hydrogen ions, flying off of the glycolytic pathway, are the real culprit, not lactate. The lactate, which is basically just pyruvate carrying hydrogen (acidity) out of the muscle, can even be used by other tissues for energy and gluconeogenesis (creation of new glucose).
In fact, the term “lactic acid” was condemned as the “Voldemort” of biochemistry. It’s a bad word; just don’t say it or bad things will happen… like mis-education.
There’s so much more to this but boring readers with competitive binding between phosphates, protons and magnesium ions is not high on my to-do list. Suffice it to say that lactate, not lactic acid (shudder), is your friend. I wouldn’t even be surprised if some form of lactate dehydrogenase supplement (LDH can form lactate) doesn’t appear when the college textbooks start changing and informational “trickle-down” occurs.
Too much acidity CAN damage the body, otherwise the body wouldn’t work to remove it from the muscle and it does cause the muscle to shut down. But there isn’t such a thing as lactic acid (at least that’s what I’m taking out of that excerpt). That being said, my comment was as meaningful as “Unicorns can’t harm you”.