How Vigorous Exercise and Lactate Support Brain Health

Denise Thomas: Could you explain what you mean when you say high-intensity?

Dr. Rhonda Patrick: You know, when I'm thinking about like a vigorous intensity, high-intensity exercise, it's really the kind of exercise where you're getting your lactate levels up. Now, most people aren't measuring their lactate, so that wouldn't be the best definition. It's the type of exercise where you're really not able to have a conversation. You're just, you're not able to talk because you're working too hard. And, and that's really when you're getting your, your maximum heart rate up to 80, at least 80% or over, you know, is, I would say, pretty good range for people that are doing a more vigorous intensity exercise type of workout, whether at least 80-85% their max heart rate.

Dr. Rhonda Patrick: But again, the talk test, like you can't, you can't really talk, you know, you're just like, there's some workouts I'm doing with Zia, there's just no, I can't talk in the middle of them. Like I'm working too hard. There's just no way. So I think that's a good, a good marker. Now, there was a period of time where I was measuring my lactate, and people might— maybe we can get into that. But I think, for me, it's one of the most important components of vigorous intensity, of high-intensity exercise, is getting your lactate levels up. And what is— what is— what are your lactate levels? Well, typically, a person at baseline at rest, your average lactate levels are around 0.9 millimolar. So they're less than 1 millimolar.

Dr. Rhonda Patrick: As you start to get exercising a little bit, you know, if you're in— if you're not doing high-intensity, you're not doing vigorous, you're doing the kind of exercise that people often refer to as zone 2, where you're able to talk, but you're a little bit breathy, your lactate levels are still above baseline, but they're below 2 millimolar, generally speaking. So that would be like, The lactate threshold. When you start to get above the lactate threshold, above 2 millimolar, then you're getting more into the vigorous zone and you're starting to get up to 6, 7, 8, 9, 10, perhaps even more. Lactate levels are really rising. And for people listening, you know, lactate is— it was thought for a long time to just be a metabolic byproduct of glucose metabolism.

Dr. Rhonda Patrick: And it's just so much more than a byproduct, you know. What happens when you're working hard, really, really hard at a high-intensity, you're not able to produce energy quick enough to bring oxygen to the little organelle that's making the energy called mitochondria. So you need oxygen to make energy, but you're working so hard that the oxygen isn't being transported there fast enough. And so your body has to switch to using glucose without your mitochondria to make energy. And it's not the most efficient way to make energy, but it's quick. When you start to use the glucose outside of the mitochondria, it's called glycolysis, then you're making lactate. That's a metabolite that's, you know, in addition to the energy that you're making, you're making lactate.

Dr. Rhonda Patrick: So it's actually used like glucose is used as energy, But even it takes less energy to use lactate to make energy than it does to use glucose to make energy. So it's energetically favorable, and your muscles use it for energy. It's also transported to other tissues, predominantly going to the brain during exercise. So lactate is a way for your muscles to communicate with other organs, other tissues like the brain. And so what lactate does is it tells the body. Hey, I'm working hard. I need more of this other thing. And so in the brain, your brain, when your muscles are working hard, your brain is also working hard. So your the lactate signals to the brain to make neurotransmitters. Norepinephrine is one. Norepinephrine is involved in focus and attention.

Dr. Rhonda Patrick: It's activating one of the most powerful neurotrophic factors ever called brain-derived neurotrophic factor (BDNF). It causes your brain. Particularly in parts of the brain that's involved in learning and memory, like the hippocampus, you're making more neurons in that region of the brain. So that's really important for brain aging, because our brain atrophies as we age. And so you're basically helping stave off some of that brain atrophy. And it also is very important for learning and memory, for improving the connections between neurons, for increasing what's called neuroplasticity. That's the ability of your brain to— be able to adapt to a changing environment. So, you know, things are constantly changing.

Dr. Rhonda Patrick: And if you can't adapt, you know, it really hinders the way your brain functions, and it causes depression as well. So, so lactate is so important for, for that as well. And I just, it's one of the reasons why I really like working out hard, because I'm very focused on brain health. And I know that lactate is essential in that equation, and to get the lactate, you have to go hard.

Denise Thomas: Yeah, it's not, it's not comfortable. So you're saying, is getting to that level of lactate production, is that your threshold? Is that where you're on the edge of breaking down? And, um, whether it's not exhaustion, but what does it practically look like if you were working out? Let's say you were doing a bunch of squats and push-ups and sit-ups. Is that where you're at fatigue and you're pushing through?

Dr. Rhonda Patrick: You can produce it before fatigue. You just have to be working hard, generally speaking. Really, it is just intensity. And so, as you start to really get to that point where you can't talk, remember the oxygen, when you're not bringing the oxygen to the muscles quick enough, You can't talk, like it's, it's, you're working so hard, your heart rate's up to like 80% max heart rate or above, you're starting to really get lactate levels up. And then as you get to fatigue, then you're maxing it.

Denise Thomas: You're, you're a huge advocate for high-intensity. I've got a quote here that you say, intensity outshines volume for mortality. And I think what you're speaking to here, and then you can, you can kind of dive into it is the research that you've done is that volume, meaning duration of effort.

Denise Thomas: So for low-intensity efforts like your zone 2s, that will move the needle a little bit, but it's very time-consuming, especially in our busy lives, that in order to get some of the benefits from there, you have to do it a lot for a long time. When you could have that minimal effective dose of shorter durations, and it's going to extend your life. So, can you speak a little bit to that? Because I think your research into how you've highlighted how important intensity is over volume, and what is volume in your eyes?

Dr. Rhonda Patrick: Well, yeah, I think the exercise volume is really the amount of time you're spending exercising, right?

Dr. Rhonda Patrick: So, I mean, if you're someone that's doing a zone 2 bike ride or a run, and when I say zone 2, I'm talking about like you can talk during the exercise, you're a little breathy, but you can still have a conversation. You know, if you're doing that, like, it's great. It's, you know, it's great to do that sort of workout. But you really have to do a lot of it to get the same mitochondrial Biogenesis benefits we talked about. Generally speaking, most people are not doing that type of volume of exercise where you're where you're training greater than ten hours a week and you're you know probably running forty miles a week or something something crazy like that where you're just you're not most people are not doing that.

Dr. Rhonda Patrick: So I do think that the intensity is it's not only time efficient; it's just so robust. You're you're you're really pushing the system to adapt. You're really pushing the system to adapt. Your cardiovascular system has to adapt, your mitochondrial, you know, function and your mitochondrial system has to adapt, your muscular system has to adapt, you know, and so all these adaptations to that intense, you know, that intense push that you're, that you're putting on your, on your different systems, your lungs as well, all of that is going to lead to greater VO2 max, it's going to lead to greater mitochondrial density, better mitochondrial function, it's going to lead to greater brain function, more neurogenesis in the brain.

Dr. Rhonda Patrick: All those things are going to happen when you're pushing that higher intensity, because that intensity is what's causing and driving the adaptations, which is essentially what you're looking for. You're looking for those adaptations. And so you have to push hard to get it. Like, if you keep doing the same thing every day, or every week, you're not going to have— like, your body adjusts, right? Your muscles adapt, like, you You have to constantly put more stress. You have to push a little harder. You can't just, you know, keep doing the same number of reps at the same weight every single time you work out. You won't— you'll have adaptations at first, but then it stops.

Denise Thomas: You plateau.

Dr. Rhonda Patrick: Yeah. And you have to push past that, right? And so that high-intensity is what you're doing. You're pushing past where everything is comfortable, all the systems are comfortable, and you're forcing them to adapt even more.