SPEAKER_00 0:14

Welcome to Practically Fit, Real Fitness Over 40. I'm Jen Chamberlain.

SPEAKER_01 0:18

And I'm Alex Johnson.

SPEAKER_00 0:20

And today we're going to talk about endorphins, endocannabinoids, and other chemicals that your brain produces in response to exercise. Is runner's high real and how can you get it? We'll talk about all that and more. But before diving into the science, I wanted to do a little self-congratulation. So, Alex, this is our 30th episode of Practically Fit. I'd say that's pretty impressive.

SPEAKER_01 0:40

Yeah, I agree. I think I think actually our biggest challenge for this episode today is just going to be to pronounce the word endocannabinoids. Yes. Yes. Stumbling over that uh as we talk through the episode. But yeah, it's exciting that we've um we've hit 30 episodes. So thanks to all the listeners and looking forward to another 30 more, and we'll see how far we go.

SPEAKER_00 1:03

Yeah, and thanks to you, Alex, because you filled in for two weeks while I was on vacation. I thought both episodes were really interesting and insightful. I hope our listeners enjoyed them as well.

SPEAKER_01 1:11

Yeah, no, that was that was fun. But I gotta say, I I missed having you on the podcast. So glad to have you back.

SPEAKER_00 1:18

And I'm glad to be back. So let's dive into the science behind all of these mysterious chemicals that cause this elusive runner's high, something I've been thinking about for probably 20 years now, actually.

SPEAKER_01 1:29

Yeah, and just the research that we've done for this episode, it really blew my mind because you know, you hear about endorphins all the time. But then when you really dig into this, it's it's fascinating. And it's fascinating that we will be talking about endocannabinoids.

SPEAKER_00 1:47

Yes, yes, indeed. So whether you call it runners high or just being in the zone, I think what most people think about, like you mentioned, Alex, when you think about that good feeling that comes from exercise is endorphins. But the science around feel-good chemicals has actually changed a little bit over the years. So definitely learn something during this podcast. Um, so what as it turns out, while the body does produce endorphins, which is kind of a natural opioid in response to exercise or stress, as it turns out, endorphins can't cross the blood-brain barrier. So they can't be responsible for that blissed-out feeling you sometimes get from exercise. So instead, scientists now think that cannabinoids may be responsible.

SPEAKER_01 2:29

You got it that time.

SPEAKER_00 2:30

All right, I knew that that time I've been working on this. Cannabinoids, like can't okay. Uh, these chemicals work to maintain homeostasis, and that's the balance in your brain and body. And just as the name suggests, they are similar in chemical structure to cannabis.

SPEAKER_01 2:45

So the runner's high is actually a very appropriate name.

SPEAKER_00 2:49

Yeah, and even funnier, because they didn't realize at the time that they sort of named it that, that it was from this sub this substance our body produces that's similar to cannabis. And interestingly, too, a note as we talk through this, endo means that your body produces it versus some synthetic form of the same chemical.

SPEAKER_01 3:07

Or something you get from a plant.

SPEAKER_00 3:09

Or exactly, or exactly, exactly. So, yeah, I found this 2021 article in the New York Times that did a really great job of summarizing several different studies pointing to cannabinoids as the true source source of runner's high. So they started way back in 2012 with a study of dogs, ferrets, and humans, and they encouraged them to run on treadmills. I would have loved to see like the little ferret treadmill that they put.

SPEAKER_01 3:36

I'm pretty sure that's the second ferret reference on the podcast in the past few weeks. I think I referenced ferrets while you were gone.

SPEAKER_00 3:43

I think you did too. Yeah. That's really weird. Well, they're not that similar to humans, and that's one of the reasons that they chose them. So dogs and humans, we're well adapted to distance running due to some uh structural things that we have. Whereas uh ferrets are not. They, as the as the article said, they slink and they sprint, but they don't really do marathon running per se. So interestingly, when they had them run through this study, the uh dogs and the humans produced elevated levels of endocannabinoids, whereas the ferrets did not because they don't get that high from running. In fact, I think they quite don't enjoy it.

SPEAKER_01 4:21

So there's no like ferret marathon that I could enter my future ferret in. Not a ferret running competition.

SPEAKER_00 4:29

No, they'd only they'd only do well on sprinting. Ferret 5K, I like that though. Hmm. Good branding for a race.

SPEAKER_01 4:38

Yeah.

SPEAKER_00 4:39

So going back to the science, a 2015 study with mice took this a step further and um blocked their endorphins and put them through a similar exercise where they had them run. Actually, mice really love to run, so they let them run on their little mice treadmills. And uh it was interesting. So when they also blocked the cannabinoids in their brains and they compared the two groups of mice, they had these two groups of mice. And when the cannabinoids were blocked, those mice were still just as anxious and twitchy, as their article says, as they were at the start. But when the endorphins were blocked, they were calmer and more relaxed. So when their cannabinoids were allowed to run through their system, that's what gave them that relaxed um feeling after their little mouse run. Following so far?

SPEAKER_01 5:26

Yeah. I'm just picturing a mouse run now. This is really fascinating research, though.

SPEAKER_00 5:34

Well, we're finally getting the humans, and this was the nail in the coffin for endorphins. And this um kind of debate went on for a really long time. I was kind of following it on the sidelines, but this was a 2021 article, and uh this article is titled Exercise Induced Euphoria and Anaxiolysis. I don't know if I'm saying that right.

SPEAKER_01 5:55

We don't know how to pronounce that, but it means decreased anxiety.

SPEAKER_00 5:58

Exactly. I had to look it up, but it decreased anxiety basically. So the article says, Do not depend on endogenous opioids in humans. There, I got through that title. Um, this study replicated the mouse study in a double-blind, randomized, placebo-controlled experiment. Participants who went through the study exhibited increased euphoria and decreased anxiety after 45 minutes of running on a treadmill in a moderate intensity range. Okay. So this happened, the important part of the study happened even when their opioid receptors, which are the things that bind to the endorphins, were blocked. So this showed conclusively that these endorphins could not be responsible for the runner's high. And now it's strongly suggested that cannabinoids are the actual cause.

SPEAKER_01 6:46

Cannabinoids or cannabinoids?

SPEAKER_00 6:49

Cannabinoids.

SPEAKER_01 6:50

See, we told you we were gonna, we will be we by the end of this podcast, we will have edited out the word can cannabinoids like 20 times. It's totally it's really hard to pronounce. We're trying. Uh so this is really fascinating. So now that we know that cannabinoids are responsible for the euphoria and decreased anxiety brought on by exercise, we were curious just how much and what type of exercise produces this effect. And so for that, we turned to a research out of Wayne State University by neuroscientist Hilary A. Morosk. A student in her lab led a systematic review and meta-analysis of 33 published studies on the impact of exercise on endocannabinoid levels. They found that acute exercise, like going for a 30-minute run or cycling, consistently boosted endocannabinoid levels across the studies. And they found further that the exercise-related boost in endocannabinoids was found across different types of exercise, including running, swimming, weightlifting, across individuals with and without pre-existing health conditions. So pretty conclusive stuff. Although only a few of these studies in this meta-study looked at intensity and duration of exercise, it appears that moderate levels of exercise intensity, such as cycling or running, are more effective than lower intensity exercise, like walking at slow speeds or on a low incline, when it comes to raising endocannabinoid levels. So this suggests that it's important to keep your heart rate elevated, that is, between about 70 and 80% of age-adjusted maximum heart rate, for at least 30 minutes to reap the full benefits of your endocannabinoid release.

SPEAKER_00 8:33

Oh, good one. You got all the way through that. You did much better on that pronunciation than I did. But you know, the heart rate thing is interesting because uh we've looked at it at this from a lot of different angles. And I think that was one of the clues for me, or one of the takeaways was you know, you have to have your heart rate at that 70 to 80 percent, and then 20 to 30 minutes is kind of like the sweet spot for getting in that runner's high zone.

SPEAKER_01 8:56

Yeah, so that's really more like it. In fact, I wrote about zone two training last week uh on practically fit on quick hits, and there was a bit about zone two training in there, and that was more in the 60 to 70 percent rate of your heart rate range. So this would be, I guess, what you would term zone three training, so more intense training.

SPEAKER_00 9:16

Yeah, absolutely. And then the other takeaway is you don't have to run to get runners high. So maybe they need actually a more inclusive term for this great feeling you get from exercise, exercise high, something like that.

SPEAKER_01 9:27

Exercise high, yeah. It's not just from running.

SPEAKER_00 9:30

Exactly. We were trying to own it for all those years, but I guess we have to give it back. Um but but before talking about our own experiences, I wanted to mention another article I came across in Time magazine just a couple of weeks ago, a fairly recent article, and it highlighted brand new research showing that exercise can also improve our ability to tolerate pain. And this was an interesting study. It used data from a really large Norwegian population of over 10,000 adults. And researchers in the study found that people with more active lifestyles were better able to tolerate pain. They measured this by submerging people's hands in ice water and having them rank their pain on a scale. Sounds fun, right, Alex?

SPEAKER_01 10:09

Yeah, this sounds like just an average day on TikTok.

SPEAKER_00 10:14

It totally does. But the more these people in the study exercised, the better their pain tolerance became, even increasing over the course of the study. So why is this important? This article notes that it's a really important finding because chronic pain, according to this article, and I'm quoting here, chronic pain is now more prevalent in the US than either depression or diabetes. And it can be really difficult to treat. We all know that, you know, a lot of the drugs to treat this are addictive and have all kinds of problems. So the fact that exercise can help in fighting chronic pain is really an amazing finding.

SPEAKER_01 10:48

So instead of even smoking marijuana to get your cannabinoids, you could just do exercise. That's what you're telling me right here, which will blunt your chronic pain. You don't have to ingest drugs. Hey, who knew? Very cool conclusion.

SPEAKER_00 11:02

Yeah, I wanted to go back to one of the other articles I was reading on the mouse studies and such. Uh it made a very clear point of saying, like, it's better to exercise than to actually use substances because it doesn't have exercise, it doesn't have the um, you know, the other side effects that those chemicals might have.

SPEAKER_01 11:19

Right. It has good effects. Right. Uh no judgment though. I mean, if you want to do it. No, no, it's cool. Yeah. If you want an eat an entire bag of Fritos this afternoon, go for it. No, I'm just kidding.

SPEAKER_00 11:31

So I thought we'd close out this episode uh in talking about our own experiences with exercise-induced bliss. So, Alex, have you ever experienced this and what what kind of activities tend to bring this on?

SPEAKER_01 11:43

Yeah, no, I think I think the research for me at least, and I'll be curious to hear your perspective, but the research is spot on. It it has to be a little bit more intense. Like, I'm not gonna get this, you know, exercise high from just doing a super slow paced run or like an easy ride on my bike or going for a low-intensity walk. Like, I my experience has always been it has to be moderate to intense exercise to induce that feeling that I previously associated with an endorphin rush and now know that is coming from my body's own sort uh you know natural marijuana. Yeah. Which is, I mean, this just blew my mind, this research. So um, yeah, no, it's tip for me, typically it would be like a more intense run or a longer bike ride where I go at a moderate to high pace. Those are the two things in recent years that have elicited this sort of response to me. I was trying to go back and think through other forms of exercise. So maybe something like HIIT training, I feel, could induce this, you know, if we're swinging kettlebells for 20, 30 minutes or boxing. But yeah, I think it's gotta be something that's eliciting more intensity. In fact, I don't ever recall getting this feeling from just doing like a standard strength workout where I take a normal period of rest in between sets, for example. But Jin, what about you? What's your experience with this?

SPEAKER_00 13:13

Yeah, absolutely the same. The same in terms of types of exercise. But after I've spent all this time throwing endorphins under the bus, I do want to say this is solely based on my own anecdotal experience. I've had this kind of feeling that they describe in the literature as sort of relaxed, blissed out after pretty much any type of intense workout, you know, an hour-long run, even a 45-minute run, a 50-minute boxing session, anything that's sort of in that elevated effort range for duration. But I've also had this interesting experience with really long distance running. And um, specifically when I was training for marathons, you know, anything over about 16, 18, 20 miles for me, running is painful. Like your body starts feeling a lot of aches and pains towards the, I don't know, three and a half hour mark. And I've had this experience where I've felt that pain and then I've like run past that and felt this other kind of high that does almost feel like a natural opioid, where it feels like suddenly the pain goes away, and you're just um I it's almost like an out-of-body experience. It's very weird. So it makes me wonder if there's more to this. I think more research could be done in this area, but definitely I've experienced different types of quote unquote runners high.

SPEAKER_01 14:28

Yeah, I've never experienced that. And to be honest, I start to feel the pain at like mile nine. So the most I've ever done is a half. So yeah, I've never I've never experienced that. That's fascinating. I'm trying to think back if I've ever felt that way with anything I've done exercise-wise, where I I can't recall a time where I've had that kind of pain and then worked through it and felt that way. So that's really interesting. We'll have to we'll have to research that some more and see if anything. That obviously, I think if you look into ultrarunning um and things of that nature would be where you might find those, those types of stories.

SPEAKER_00 15:06

Yeah, definitely. And you see it too. I was a volunteer at the finish line of a marathon one time and just seeing people's, I mean, people cross with, you know, tears streaming down their face and just with all these like extremely emotional responses. So I think it's interesting. I'd I I'd love to see more about that, you know.

SPEAKER_01 15:23

Yeah, absolutely. So that was super interesting research. Uh, we've learned a lot today. We learned that, you know, it's not endorphins that are responsible for this quote unquote runner's high that we've we've all felt if we've been running or doing other forms of exercise for a long time. It's it's endocannabinoids, which are very similar to what you might find in marijuana or other, you know, CBD, all these things that, you know, these stores that are popping up across the country now. It's all the same concept, right? And that I've I just think this was this was mind-blowing research. I this is what I read through this research and thought, wow, I've learned something new today. So hopefully folks on the podcast are feeling the same way. And I think the other thing we learned here is that it really takes moderate to higher levels of intensity in terms of exercise to induce this sort of exercise high that you can feel from from working out.

SPEAKER_00 16:19

Absolutely. And we'd love to hear your stories of runners high, fitness high, whatever it is. I I'm fascinated by this subject as well, and would love to hear other people's thoughts on it in the comments or reach out to us via email.

SPEAKER_01 16:31

Yeah, bottom line, next time you want to get high, go for a run. There you go. All right. Well, Jen, great episode today. As always, please head out to practically. Also, if you enjoy the podcast, please feel free to leave us a review on iTunes. We're really excited to be up to 30 episodes, and we're seeing the downloads continue to grow. So we appreciate everyone who's been listening. But until the next time, remember, fitness is for everybody.