How Lactate & Metabolism Influence Performance

**Andy Galpin** (0:00)
The science and practice of enhancing human performance for sport, play and life.
Welcome to Perform.
Hello friends, I'm Dr. Andy Galpin. I'm a professor of kinesiology in the Center for Sport Performance at Cal State Fullerton. In today's show, we're going to be talking about lactate, or how many of you probably think of it, lactic acid.
Now, I know when I say those words, you immediately start thinking about things like exercise and muscle and fatigue, soreness and reducing exercise performance, and that all is true, kind of. In fact, as we're going to lay out, the overwhelming perceptions and thoughts about what lactate or lactic acid really are and what they're doing are massively false. In fact, I'll spill the beans right now. Lactate is in no form or fashion cause of your muscle fatigue.
It actually does quite the opposite. It preserves muscle performance. We'll get into all that stuff later. In fact, I actually think that highlights why I wanted to have this conversation or do this episode is because it's high time we start really understanding what lactate truly is and how it's functioning in our body. It has classically been thought of as this waste product, something that you don't want around, something that you want to avoid at all costs or manage or mitigate whenever possible. And the reality of it is it has a number of widespread benefits across your entire physiological landscape. Let me give you a couple of examples of what I'm talking about. Lactate is known to stimulate a molecule called PGC-1 alpha. This is involved in any metabolically active tissue in any part of your body, and it is directly responsible for mitochondrial biogenesis. This is another way of saying, by increasing and utilizing more lactate, you're gonna be increasing and making more mitochondria. This is a known response, and this is obviously a positive thing for overall health and performance. But it even goes beyond that. Let me give you a couple of other examples you may not realize. For example, did you know lactate targets latex cells, which are responsible, of course, for testosterone in your body?
It has a number of other benefits, such as BDNF, so brain-derived neurotropic factor. This works directly on the hippocampus to stimulate neurogenesis, so the growing of new neurons, particularly in your brain. Similar idea with a molecule called VEGF, which is responsible for endothelial cells and then therefore promoting angiogenesis, so the growing of new vasculature throughout your entire body.
Grelin, which is associated with hunger, so lactate actually acts directly on the hypothalamus to regulate grelin, and one of the major benefits here is suppression of appetite. I don't need to explain a lot to you there, but very few people can do a high intensity exercise spout where they generate a lot of lactate and then feel extremely hungry immediately afterwards. So appetite suppression with high lactate is a pretty easy one to imagine.
I'm gonna go even further though, because there's so many more things lactate's doing. Whether we're talking about the liver and the kidneys and increasing what's called gluconeogenesis, so as you'll see later in our conversation, the primary place that we're getting the molecule or precursors for gluconeogenesis is lactate. Another benefit is the ability to act on osteoclasts and therefore play a role in bone remodeling. Now I could go on and on here, and we're not quite done yet because I wanna give you a handful of ones. I'm gonna rapid fire these ones. But lactate, again, has been highly associated with positive adaptations across your brain. It's heavily involved in memory and learning.
Heart health, dehydration. In fact, any of you that have ever used a Ringer solution, I know exactly what I'm talking about there. Cancer, sepsis, insulin regulation, traumatic brain injuries, wound healing, post-surgery recovery, arthritis, inflammation, gut microbiome health, and then finally overall metabolic flexibility. My guess is you had no idea that many things were happening in response to lactate. So in order to understand all these things, what I would love to do is spend a little time today walking you through exactly what lactate really is, how it's created, how it's managed, what role it's truly playing in your overall physiology. And then of course, at the end, we'll do our three I's, which is investigation. How do I measure this stuff? What should I be paying attention to? Two, interpret. How do I know if I'm good, bad, great, terrible, or world record? And then three, intervene. How do I improve my body's ability to produce and clear lactate so that it can perform at its highest level regardless of the task I'm asking my body to perform? To get us started on this journey, we're gonna go all the way back to the beginning, when we initially discovered and began to understand the role of lactate in really all of biology, but specifically in human exercise physiology. The story really starts in 1708, when Scheele found lactate in sour milk. Now, the term he gave it actually roughly translates, I think, into milk acid, but it really persisted in this idea of just general food space until nearly 30 years later, in 1808, when a scientist, Berzelis, and I have tried to pronounce this at least 200 times, but Berzelis really, and this is a classic story in all exercise physiology cycles, he found that concentrations of lactate were much higher in hunted stags, so a deer-like creature in Europe. And so it was very clear at this point that lactate is somehow associated with elevated stress or exercise, and we didn't really know much past that, but it seemed to be in all of physiology at this point. So we had now crossed over from things like food elements and bacteria into now human physiology. So that was really a big step up in terms of our understanding of the relative importance of it for living creatures. Now, Berzelis went on to do a whole bunch of other stuff in this field, and in fact, he was directly responsible for the name that you all probably recognized as a catalyst. By studying lactate and trying to figure out what's going on, he really came up with this idea that he called ferments. Now, that sounds familiar because it is where we got fermentation from, and in fact, you may be starting to make a connection in your brain, which we'll do a little bit more directly later, that really lactate and fermentation are almost one of the same. In a human exercising muscle, we call it anaerobic glycolysis and lactate production. In food elements and in the food industry, we call it fermentation. Not exactly the same, but very, very close, and I'll maybe explain that a little bit more later. We haven't really moved into the realm yet of exercise physiology. There was no real understanding that this was happening as a byproduct of muscular contractions or anything like that at this time. We were still at the level of understanding what happens when carbohydrates are used with and without oxygen. So, in fact, we can be more direct here. When we break down carbohydrates for a fuel source, that's fermentation. You do the same thing with protein. We call that thing putrefaction. Same thing happens with fat, and you call it rancidification. And so, in fact, you may have never made that connection before, but you ferment carbohydrates, fats go rancid, and proteins are putrefied. So, at this point in the story, we're kind of in the mid 1800s. In fact, in 1843, Schurter was the first to find lactate in the blood. He actually was autopsying folks that had died from septics and fevers and infections and things like that, and noticed during these bouts of really high fever. So, we now know that, of course, that's really high caloric expenditure, really high need for energy, high temperature, et cetera, et cetera. You've gone through a lot of metabolism and lactic concentrations were really high. We hadn't really associated this with muscle yet and certainly hadn't done it with exercise. And we were actually, at this point, thinking it was something that happened to be associated with death. The stags had been dying folks, these folks had been dying or dead, and that's all we knew at this point. It was another 15 years or so, the late 1850s, when they first started finding this in the blood of actual living people. And this changed everything. In fact, for the next 50 years or so, most of our breakthroughs were from a gentleman named Louis Pasteur. You're probably familiar with him. And in fact, all the stuff that we do with milk and we pasteurize it, all this is from Pasteur's original work. And so there was all these associations that were floating around, and then really everything came to fruition with the very classic series of papers in 1907 from a combination of folks. One of them is the authors, Hopkins and Fletcher, were really the first to identify that lactate was a byproduct of muscle contraction. And then a handful of years go on, and two very famous scientists, both whom won Nobel prizes, Otto Meyerhoff and AV. Hill, put together what most people, and certainly at the undergraduate or graduate exercise physiology level, now understand as basic lactate metabolism. We are now understanding things like it's coming from carbohydrates, it's coming from muscular contraction, there's an association between more metabolism, more lactate production, and all that fundamental stuff. And while they certainly got many things wrong, Meyerhoff and AV. Hill are the ones most credited with our basic understanding of the differences between anaerobic metabolism and lactate being a core cog in that discussion. In 1960, lactate analyzers came on board and the field exploded. And one of the more fundamental things that happened was a paper published by Wasserman in 1964, in which he outlined a concept called the anaerobic threshold. Now, what he was basically saying there is, at some point when you're producing energy and you need more of it, you switch from aerobic into anaerobic metabolism. And there's a threshold for everyone in which you can no longer produce energy aerobically and you have to switch to anaerobic metabolism. If I missed you with all that stuff and you don't really know what those terms are, I promise I'm gonna come back and walk you through that all in just one second. But this concept of the anaerobic threshold from 1964 persisted for a very long time.