Running: Will It Wreck Your Body?

Summary

Science Vs – Running: Will It Wreck Your Body?

Date: April 16, 2026
Host: Makete Foster Keys (filling in for Wendy)
Guest Contributors: Meryl Horne, Dr. Rasmus Ostergaard Nielsen, Professor Dukschul Lee ("DC"), Dr. Michael Sievers

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Episode Overview

This episode pits popular opinions about running—its risks, rewards, and that mysterious “runner’s high”—against the scientific evidence. The show explores whether running is more likely to wreck your body or make you healthier, how to avoid injuries, the unexpected importance of your glutes, and what’s really happening in your brain when you feel euphoric mid-jog.

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Key Discussion Points & Insights

1. Running: Popularity, Perception & The Injury Debate

[00:00–03:22]

• Kickoff: Running is widely practiced; over 28 million people run weekly in the U.S. Is it really good for us, or is everyone who gets into running doomed to injury?
• Quote:
  • “Everyone I know that starts to get into running, their body slowly starts to fall... don't run, period.” (01:00, various voices)
• Injury Anxiety: Both the host and producer share personal and family injury stories to highlight common fears about running.

2. Injury Rates – How Likely Is It To Get Hurt?

[03:23–06:08]

• Scientific Comparison:
  • Runners get injured more than swimmers or cyclists.
  • “One big review… said that typically half of runners get hurt every year with an injury that keeps them from running.” ([05:13])
• Body Parts Most At Risk:
  • 30% knees
  • 20% lower legs/shins
  • 13% ankles

3. Why Do Runners Get Injured?

[06:08–13:05]

• Myth Busting: High-impact ('wear and tear') is commonly blamed, but new research shows the bigger culprit is ramping up distance too quickly.
• Interview with Dr. Rasmus Ostergaard Nielsen:
  • Study tracked over 5,000 runners for 1.5 years.
  • Increasing your weekly run by just 10–30% over your average boosts injury risk by 60%. ([08:29-08:37])
  • “If you want to be in the safe zone, then you need to reduce the length of your running session.” ([09:50], Dr. Nielsen)
  • The safest guideline: increase your distance by no more than 5% per week.
  • Memorable Moment: Even the expert admits he struggles to follow this rule when peer pressure or excitement hits. ([10:38-10:59])

The Slow Adaptation Trap

• Cardio improves fast, bones & tendons don’t:
  • “Your cardiovascular system adapts quickly… pretty soon you’re breathing easier… but your bones can take months to adapt.” ([11:39–12:13])
  • This can give beginners false confidence and set them up for overuse injuries.

Running Form & Injury Prevention

• Debate Over Foot Strike:
  • Heel vs. forefoot striking: May shift the burden (less knee, more ankle/foot), but no form is a magic bullet. ([12:28–12:55])
  • Slow ramp-up outweighs stride tweaks for injury prevention.

The Surprising Power of… The Butt

[13:05–15:49]

• Strength Matters:
  • Study of NYC marathoners: Only one exercise predicted lower injury rates—the single-leg glute bridge.
  • Holding a single-leg glute bridge (esp. on the weaker leg) for 20 seconds = 64% lower injury risk. ([14:30–14:40])
• Why?
  • “Muscles in your butt help keep your hip joints stable and… your hips and knees in proper alignment.” ([14:42])
• Jenga Analogy:
  • “That’s a critical piece in the Jenga tower. The butt, it’s right there in the middle.” ([15:25])

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4. Running: Do The Benefits Outweigh The Risks?

[16:04–21:36]

Longevity & Disease: The Big Picture

• Interview with Prof. Dukschul Lee (“DC”):
  • His study tracked over 55,000 people for 15 years.
  • Runners live longer: “Running was associated with significantly lower risk of death compared to not running.” ([17:47])
  • Especially effective for lowering:
    • Cardiovascular disease
    • All-cause mortality
  • Mechanisms: Lowers blood pressure, improves cholesterol and glucose, reduces chronic inflammation.
  • You can get these benefits with other cardio—not only running.

How Much Do You Have To Run?

• Surprise finding:
  • “People who ran less than one hour per week basically got the same benefit as people who ran more than three hours per week when it came to longevity.” ([19:11–19:25])
• Just 5–10 minutes per day yields major longevity benefits.
  • “Moving from sitting all day… to even very small amounts of any type of physical activity will provide health benefits. That’s for sure.” ([20:12], Prof. Lee)
• Ultra-Runners & Heart Health:
  • Only men who run 3+ hours per day (10x the recommended amount) have increased risk of some heart issues. For everyone else, running is good for the heart.

Memorable Quote:

• “The TikTok doctors are leading you astray, Meryl.” ([18:51], A)

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5. Running & The Brain: The Science Behind Runner’s High

[21:39–28:36]

What Does the Science Say?

• Runner’s High is Real & Common:
  • “One study… around 70% of endurance runners have reported having this runner’s high at least once.” ([22:47])
• What Causes Runner’s High?
  • For years, endorphins (natural opiates) got the credit.
  • Newer research points to endocannabinoids (the body’s own “weed-like” chemicals). ([23:47])
  • Key Experiment by Dr. Michael Sievers:
    • Blocking endorphin receptors didn’t block the high.
    • Endocannabinoid levels rise during prolonged running.
    • Mice without cannabinoid receptors ran 30-40% less—suggesting they missed the reward. ([25:56])

Memorable Quotes:

• “It’s kind of like a chemical cocktail party going on up in your body.” ([27:01], A)

How To Get Runner’s High?

• Go for 20+ minutes at vigorous-but-not-max intensity.
  • “At 35 minutes, more or less, you’re having the best mood results in the studies.” ([28:08], C/Dr. Sievers)
  • Set the vibe for max joy: “If you like to run in nature, then… nature. If you like music, play music… in groups or alone.” ([28:08–28:36])

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Notable Quotes & Memorable Moments

• “Numbers don’t lie. And if you want to be in the safe zone, then you need to reduce the length of your running session.” – Dr. Nielsen ([09:50])
• “If you have a strong butt, your hips and knees stay in alignment—they’re like the Jenga stack piece in your body.” – A & B ([15:13–15:25])
• “People who ran less than an hour per week got basically the same benefit as people who ran more than three hours per week when it came to longevity.” – A summarizing Prof. Lee ([19:11–19:25])
• “The blockage of the opioid systems did more or less not hinder a runner's high.” – Dr. Sievers ([25:07])

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Timestamps for Important Segments

| Segment | Timestamps | |--------------------------------------------------------|--------------| | Injury risks vs. perception | 00:00–05:13 | | What kind of injuries, and their prevalence | 05:13–06:08 | | Why injuries happen, safe increase guidelines | 06:08–10:18 | | Importance of the glutes for injury prevention | 13:05–15:49 | | Benefits: Longevity and how much is enough | 17:10–20:12 | | Is running bad for the heart? | 20:40–21:36 | | Mental health, runner’s high, what causes it | 21:39–26:41 | | How to achieve runner’s high | 27:11–28:36 |

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Conclusion: Should You Run?

• Injury Risks: Significant, especially if you ramp up distance too fast—but manageable if you follow the 5% rule and build glute strength.
• Benefits: Impressive impact on longevity, heart health, and mood. Just a little running goes a long way; you don’t have to go hard or long.
• Runner’s High: Very real, caused primarily by endocannabinoids; best achieved with 20–35 minutes of vigorous running in an enjoyable setting.
• Best Advice:
  • Ramp up gradually (≤5% weekly increase)
  • Do “booty exercises” (especially single leg glute bridges)
  • Don’t obsess over distance or form tweaks
  • Start small—even 5–10 minutes a day helps
  • Savor the process and, if you’re lucky, the high

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Final Memorable Moment

• “Now I can get a fat ass too.” – A ([29:17])
• “That’s what we really learned: fat asses equal healthy running.” – B ([29:24])

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For sources and further reading, see the citations in the episode’s show notes.

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Science Vs brings the facts, so you can run with confidence—or take a break with scientific peace of mind.

Transcript

[A]

Hi, I'm Makete Foster Keys filling in for Wendy. And you're listening to science versus the show that pits facts against 5Ks. Today on the show Running. More than 28 million people go running every week in the U.S. according to one survey. And the reason why we do this is presumably because it's good for us, right? And not only that, but we hear running can give you this sort of amazing feeling. It's time to get high. Runner's high, that is.

[B]

I had ran two miles straight and I experienced a runner's high for the very first time. It was so freaking cool. It was like full adrenaline.

[A]

So a lot of us are excited about the benefits of running, but then we also might have this nagging voice in our ear that's kind of just like, you're gonna get hurt. Everyone I know that starts to get into running, their body slowly starts to fall. Ap don't run, period.

[C]

I'm so tired of saying it. Your knees go. Your ankles go. Your hip goes.

[D]

Running is terrible for you. And anybody who runs a marathon, I think, needs mental health help.

[A]

And so today we're running down the science here. We're gonna figure out what actually happens to our bodies when we run, what's going on with our muscles and our joints. And then we're also gonna look into runner's high and figure out, like, what's happening in our brains when this happens. Because when it comes to running, there's a lot of their body slowly starts to fall apart. And then there's science. That's coming up after the break.

[E]

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[A]

Welcome back. I'm Maketi Foster Keys, and today we're looking at running and what it's doing to our bodies. With me today is senior producer Meryl Horne. Hey, Meryl.

[B]

Hey, Keddie.

[A]

So are you a runner?

[B]

I am a runner. Like, I don't run as much as I used to, but I love running. It's like my little escape, you know? I love it when I'm listening to the music and getting into the rhythm.

[A]

I actually publicly hate running, but secretly kind of love it. I don't do it as much, though, because I got hurt.

[C]

Yeah.

[B]

I mean, I'm also scared right now to really get back into it since my husband got super injured from running. Like, he. He wasn't doing anything that crazy, but he ended up getting a stress fracture and literally, like, just couldn't walk one day because of it and ended up being on crutches for, like, two months.

[A]

Oh, my God.

[B]

Which I just didn't even realize could happen. So that. That really freaked me out.

[A]

Geez.

[G]

Yeah.

[A]

So that's actually where I wanted to start with injuries like, how likely are you to get hurt as a runner? And I wanted to compare running with stuff that's also pretty accessible. So I looked at cycling and swimming, and there are lots of studies. They'll survey people about what they do and if they got hurt. So, like, one review will look at runners over a period of time to see, like, okay, how much did you run? What kind of injuries did you get? Another review will look at cyclists and then swimmers.

[B]

Okay.

[A]

Look at these reviews side by side. What you find is that runners do get hurt more often.

[B]

They do. So it's not just in our heads. Runners actually are more likely to get injured.

[A]

Yep.

[B]

Okay. That's sort of satisfying, actually. It feels true.

[A]

Right. The actual numbers, they kind of differ across studies. So one big review that I found said that typically half of runners get hurt every year with an injury that keeps them from running.

[B]

Whoa.

[A]

For a little bit. Whoa.

[B]

So about half of runners get injured every year?

[A]

Yeah.

[B]

Whoa. Okay. That sounds pretty bad. And so what types of injuries were they getting?

[A]

Yeah, so it's basically the stuff that you would expect right from the knee down.

[B]

Okay.

[A]

The best review that I could Find on this, looked at 42 studies and found that generally the most common type of injury was in the knees.

[B]

Okay.

[A]

I was about 30%. Next up, about 20% of injuries were in the lower leg. So that's between your knee and your ankle, like your shin area. And then about 13% were ankle injuries.

[B]

Okay. But so generally knees on down, bad news for that part of your body if you're a runner.

[A]

Yeah.

[B]

Do we know why this is happening? Like, is it just that, like impact of the grounds, like your body pounding on the pavement?

[A]

Yeah. So that's one thing that we've thought for like ages, Right. That it's wear and tear.

[B]

Uh huh.

[A]

After all, running can be super hard on your body. Every time your foot hits the ground, your knees absorb more than four times your body weight.

[H]

Oof.

[B]

Okay. Yeah, that's a lot. Doesn't seem like that would be good for the joints.

[A]

Right? It doesn't. But then for some people, they run and they're just fine. So I wanted to know what puts us at risk of getting hurt while we're running and is there anything that we can do about it? So I called up a researcher who did a big study on this. His name is Dr. Rasmus Ostergaard Nielsen. He's an associate professor in the public health department at Aarhus University in Denmark. And he's also a runner himself, but he wasn't always as keen on it as he is right now. So I heard that you got into running because you came in dead last in a local race in your hometown.

[G]

That was absolutely correct. I signed up for road race with a friend and I really, really, really had to fight my way through. And I came in second last in the race and that really was the start of my running career.

[A]

So since that humbling defeat in the road race, Rasmus has pretty much made running into his science career. And last year he published this paper that looked at why so many runners are getting knocked off their feet by this sport.

[G]

Many runners say, oh, I had this single run where I just ran too far and then my knees starts to hur. I thought, okay. This actually challenges the assumption that we have from clinical textbooks which would describe that overuse injuries amongst runners develop gradually over time, over weeks.

[A]

So Rasmus put together a study to look for patterns of when people got hurt. He and his team followed over 5,000 runners for about a year and a half and looked at how much they ran on average and then took a look at the times where they ran more than their average distance and also took a Look at how often they got injured after those runs. And what Rasmus found was pretty wild. If you run just a little bit

[G]

farther, you increase your risk to up to 60% larger.

[A]

Oh, that's a lot.

[G]

Yeah, that's. It's quite a lot.

[B]

Hmm.

[A]

Yeah. So for that big increase in risk, Rasmus saw it when people upped their distance just 10 to 30% over their longest run the week before. Just making that small change, that's when people had a 60% higher chance of injury.

[G]

Whoa.

[B]

So you gotta be really careful, like, you're not messing around when you even just go that little bit more.

[A]

Yeah. So Rasmus says that you can bump up your distance safely, but in order to do that, you shouldn't run more than 5% farther than what you usually do.

[B]

Got it. 5% more. Okay. So, like, don't. Don't get too excited. Like, just take it really slow.

[A]

Yeah, I mean, of, like, don't get excited at all. It's really not that much more. I asked him about it, so I'm like, if I run 5k most of the time in my next training session, I want to run farther. That means I can't even go 6K.

[G]

No, no, no, you can't. 6K would. Would. Would then be a 20% increase.

[A]

I think that most runners would be really upset to hear this.

[G]

Ye numbers doesn't lie. And if you want to be in the safe zone, then you need to reduce the length of your running session.

[B]

This is actually very satisfying because I thought my husband was ramping up slowly, but he was not going that slow. So now I feel like we have an explanation for basically why he got so injured. Because he was going up. Yeah. At least a mile every week. And apparently that's crazy to do that much. So. Okay.

[A]

And obviously, there's individual differences here. You know, like, your friend might be able to do a little bit more running than you without getting hurt, but 5% is the general rule that Rasmus is suggesting.

[B]

Okay.

[A]

And even Rasmus, who's an expert in this field, has a hard time with keeping himself from running more than he should. Right.

[G]

If a friend come and say, okay, Asmus, should we go out on a long run, and we should do that very fast, and I get excited, I lose my mind. And even though I know when I go out for this running session, this is totally stupid, I really shouldn't do this. And then I sustain an injury.

[A]

Yeah. And actually, one of the reasons why we might have this impulse is that our body can kind of give us Mixed signals here, because there's this kind of cool thing that's going on when we run. So as you're putting pressure on your body, you get micro injuries, micro cracks in your bones, changes in the collagen of your tendons. And when those heal, you actually get stronger. So over time, running can be really good for your body. Like, runners tend to have less arthritis in their knees.

[B]

Okay, wait, so in general, you're running along, you're getting these little micro cracks, but that's actually a good thing, because then when your body heals, it, like, builds back stronger.

[A]

Yeah, but that process can take a while, you know, like, it can take bones months to heal and get stronger. And for tendons, it can be pretty similar, but it ranges. But there's this other part of our body that tends to adapt a lot faster, our cardiovascular system. So you might find that you start out, like, huffing and puffing, but then pretty quickly, maybe even within a matter of weeks, you might start to notice that you're breathing easier and your heart might not feel like it's beating out of its chest so much.

[B]

So then you might get a little carried away because you're like, I can do this. I feel so much better. But you don't know about those micro cracks in your bones.

[A]

Or do you? Because your shin is acting up and you're just deciding, well, I want to keep running anyway.

[B]

Right, Right.

[A]

So the slow ramp up is important.

[B]

Okay.

[A]

And a lot of people talk about your form here. You know, your stride. There is some evidence that switching from running on your heels to running on the balls of your feet can reduce the load on your knees. But at the same time, doing that could also shift more of that force onto your ankles and your feet.

[B]

All right, so there's no secret stride that science is saying this will save you from getting injured yet.

[A]

Right. Like, overall, it's just not super clear that making these changes reduces your risk of getting injured. Rasmus told me that the slow ramp up probably makes more of a difference here.

[B]

Okay, good to know.

[A]

And there's another big thing that you can do here to prevent yourself from becoming, you know, just another run running statistic. Like what, Meryl? It might be time to start getting ass to grass and building up that booty.

[B]

So the butt can save us if we have a really strong butt.

[A]

Yeah. So there's this one study that looked at runners who were training for the New York City Marathon, and they got them to do these exercises to see how strong they were. It was stuff like planks Single leg glute bridges, push ups.

[B]

So they would, like, see how long they could, like, hold one of these poses.

[A]

Yeah, See how long they could hold the pose. See how many push ups they could do, stuff like that. And then they looked at who got hurt and who didn't while they were training to see if any of their strength made a difference. And what they found was that the only exercise that made a difference was the single leg glute bridge. It was the only one that cut down their injury risk.

[B]

Wait, what's a single leg glute bridge?

[A]

Okay, so in a regular glute bridge, you lie on your back with your knees bent and your feet flat on the ground, and then you push through your heels to, like, lift your butt off the ground.

[B]

Okay, like a bridge pose in yoga.

[A]

Yes, but with the single leg glute bridge, you're just doing it with, like, one leg instead of both on the ground.

[B]

Okay, I can picture that.

[A]

And people who could hold this for at least 20 seconds, specifically on their weaker leg, had a 64% lower risk of getting hurt while they were training.

[B]

Why is the butt so important?

[A]

So one explanation I've seen is that muscles in your butt help to keep your hip joints stable and also help to keep your hips and knees in proper alignment.

[B]

Huh?

[A]

Yeah. So when your butt muscles are weak, the body adjusts by moving in these, like, new ways that can put more force and, like, weight on your joints.

[B]

Oh, interesting.

[A]

Like, your knees might rotate inward more, or one hip might be higher than the other.

[B]

They get a little wonky if the butt isn't, like, holding everything in place.

[A]

Yeah, exactly. So if you're moving differently, then, like, basically the Jenga stack of your body is kind of off balance.

[B]

Right. Because it's like, that's a critical piece in the Jenga tower. The butt, it's right there in the middle.

[A]

Yeah, yeah, yeah.

[B]

So important. Wow. Newfound appreciation of the butt. Okay.

[A]

And just generally, muscles are great shock absorbers. So strengthening all these muscles, you know, around your butt, your hips, and your joints, they really help to stabilize everything and prevent injury.

[B]

Okay, so do the booty exercises.

[A]

Do the booty exercises. Yes. Yeah. So, Meryl, that's kind of all we have to say about injuries. What did you learn?

[B]

I feel like I learned a lot. You know, I know to do the booty exercises and that it's also way more likely that will get injured if we ramp up too quickly.

[A]

You're a good student, Meryl.

[B]

Yay. But, okay, well, so I guess overall, my question is still, like, then should I run? Like, do the pros outweigh the cons?

[A]

That's coming up after the break.

[B]

All right,

[D]

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[A]

Welcome back. I'm Makete Foster Keys here with Meryl Horne.

[B]

Hi.

[A]

And so far, we've talked about injuries, you know, all the reasons why you might not want to run. But now let's talk about the benefits.

[B]

Yes. Finally. All right, what are the good things?

[A]

So, for this, I talked to Professor Dukschul Lee. He studies physical activity at the University of Pittsburgh.

[H]

People call me D.C. as in Washington,

[A]

D.C. so, D.C. did this huge study a while ago that was focused specifically on running and longevity. It looked at over 55,000 adults over 15 years. And what he found was basically that runners live longer.

[B]

Okay.

[A]

Running was associated with significantly lower risk of death compared to not running. And here they specifically looked at cardiovascular disease and something that's called all cause mortality.

[B]

Okay. Oh, and both of those things were lower. The runners?

[A]

Yeah, yeah, both of those things were lower.

[B]

Nice.

[A]

And DC Told me that the reason why running increases longevity is because it does things like lower your blood pressure, improve your cholesterol, and improve your glucose levels. So all this stuff is super important for your heart.

[B]

Okay.

[A]

It also can reduce chronic inflammation, which is linked to a whole bunch of diseases.

[B]

I mean, it is nice to hear. It's not surprising.

[A]

Yeah. Now, it's possible that people who are already healthy and therefore likely to live longer anyway, that they're also more likely to be runners.

[B]

Oh, right.

[A]

But the study did try to take that into account.

[B]

Okay, well, that's really. I mean, I feel like that's so different from all the scary TikTok doctors that I've seen. Like, if it's overall gonna make us live longer, it can't be that bad for us to run.

[A]

The TikTok doctors are leading you astray, Meryl.

[B]

Yeah.

[A]

And it brought up another question for me, which is, like, how much do I actually have to run if I want to live longer?

[B]

Oh, yeah.

[H]

People may think, no pain, no gain. You know, the more, the better regarding exercise and health. Right.

[A]

But what DC Found kind of turned that idea on its head. His study found that people who ran Less than one hour per week. Basically got the same benefit as people who ran more than three hours per week when it came to longevity.

[B]

Whoa.

[A]

Yeah. Here's dc.

[H]

I was surprised that doing more was not, you know, was not providing more benefits. You know, when I published that original paper, lots of serious runners were unhappy because, you know, again, the benefits from pushing further was more.

[B]

So it really doesn't matter. Like, you don't need to worry about running extra hard if what you're going for is, like a boost in your longevity.

[A]

Yeah, exactly. And you can even break that one hour of running down into just five to ten minutes per day. Whoa.

[B]

Five to ten minutes a day. That's it. That's all you need to do. Okay.

[A]

Yeah.

[E]

Nice.

[A]

So for dc, this is the bottom line.

[H]

Moving from sitting all day like a completely sedentary, to adding even very small, very small amount of any type of physical activity will provide health benefits. That's for sure.

[A]

And we should say that even though DC study looked at runners, this goes beyond just running. You can get these benefits from other kinds of cardio exercise, too.

[B]

Okay, sure. Right.

[A]

And by the way, all of this was especially interesting because there's this idea that our listeners brought up that running is bad for the heart, but that's not true.

[B]

Yeah. This doesn't seem like it dives with what you've been saying.

[A]

Right.

[B]

Okay.

[A]

It seems like this does come from a little bit of evidence. You know, like, some studies suggest that men who run a lot have a higher risk of some heart issues.

[B]

Oh.

[A]

But that's men who run a ton. Like, 10 times more than the weekly recommended amount.

[F]

Whoa.

[B]

Okay.

[A]

Yeah. It works out to something like three hours per day.

[H]

Whoa.

[B]

So for that very specific group of men, you said. Yeah, men, then they might have an increased risk for some heart issues, but for all the rest of us, we're okay. It's actually good for the heart.

[A]

Yeah. So running good for the heart, overall, good for not dying.

[B]

Looking pretty good.

[A]

Exactly.

[B]

Okay, so it's good physically for our bodies. Are there any, like, mental health benefits to running? Because it does feel amazing. Like, that's why I run.

[A]

We know that exercise generally is good for our mental health. Like, there have been a few clinical trials that show that exercise can help treat depression. There's also some evidence that it can help with anxiety and ruminating thoughts. And on top of that, we do hear that there is something special that running can do for us. It's time to get high. Runner's high. That is so, Meryl, have you Experienced runner's high before?

[B]

Yeah, for sure. I mean, sometimes it does kind of feel like a high. Like, I get this lightness, and I'm just kind of, like, bounding along. I'm picturing myself, like, running next to the water near my house, and it's just so beautiful. And the music is in my earbuds, and I'm just like, ah. Like, it feels great. It's almost giving me life.

[A]

Yeah. And by the way, you can get this feeling from other types of endurance exercise, like biking, for example. But we hear people talk about it most specifically with running.

[B]

Okay.

[A]

And one study I found said that around 70% of endurance runners have reported having this runner's high at least once. So I wanted to know what's going on in our brain when we get runner's high. Yeah.

[B]

How does it happen?

[A]

So for a long time, scientists had one key. Endorphins. These are the natural opiates that our bodies make.

[C]

They found the endorphins, and they were responsible, you know, for all the feelings like eating chocolate.

[A]

That's Dr. Michael Sievers. He's a scientist at the Institute of Forensic Psychiatry and Sex Research at the University of Duisburg, Essen, in Germany. And he told me that scientists found endorphins around the same time as the runner's boom, which started in the 70s. And since they were associated with all the things that could make you feel good, you know, food, sex, laughter. They were an obvious choice to explain runner's high. But then this other suspect entered the ring. Here's Michael.

[C]

So in the 90s, they discovered a new system, the endocannabinoid system, which is everywhere in the body. And, well, in the end, there was the question, okay, is it the endocannabinoids or the endorphins which are producing the runner's high?

[A]

So endocannabinoids can also make us feel good. It might not surprise you, Meryl, to learn that they also work with the same receptors that contribute to other kinds of highs.

[B]

Yes, the weed one, specifically. And so how did Michael figure it out which one it was?

[A]

So he did a study where they basically block the receptors in our brains that get activated by endorphins. Huh. These are the same receptors that get activated if you take an opioid drug. And to block them, they actually use a medication that's given to people with substance abuse issues.

[B]

Okay. If you take it and then you try to get high, you won't actually feel the high.

[A]

Yeah. And so if runners take this pill and they don't get runner's high, then we know that the runner's high is the endorphins because the drug has blocked the endorphins, which means that it would block the runner's high.

[B]

Okay.

[A]

So what michaelsteam does is they have runners come into the lab, take either a placebo pill or the blocker, and then get on the treadmill for 50 minutes.

[B]

Okay.

[A]

And then before and after each session, they test for their mood and their anxiety.

[C]

The blockage of the opioid systems did more or less not hinder a runner's high. So we could demonstrate that the runner's high does not depend on. On endorphins.

[B]

Does not depend on endorphins. It's not the endorphins. It's something else. Like the endocannabinoids, I guess.

[A]

Yeah. Michael thinks it's the endocannabinoids.

[B]

Okay, so. But why does he think it's endocannabinoids specifically and not just some other thing in the brain?

[A]

Yeah. So Michael and his colleagues did look at endocannabinoids in this study, and they saw that they went up during the run.

[B]

Okay.

[A]

And then we also have mouse studies on this. There was this one study that looked at mice running on a wheel, and this time, some of the mice had their cannabinoid receptors either blocked or missing.

[B]

Huh.

[A]

They compared them to other mice that didn't, and they found that the mice with the blocked or missing cannabinoid receptors ran less than the other mice by, like, 30 to 40% because they were

[B]

not feeling the runner's high, I guess, like, they were kind of bummed out. So, like, why am I even running on this wheel? What's the purpose of. Of life?

[A]

I'm gonna stop

[B]

right.

[A]

Aww.

[B]

Poor mice.

[A]

Yeah. Bottom line, it seems like the endocannabinoids are the big deal here. Okay, But Michael doesn't think that endorphins are doing nothing while we run. There is some evidence that endorphins can do other stuff. Like, we think that they can make your muscles hurt less while you're exercising or after.

[B]

Okay, that makes sense.

[A]

And then there's other stuff going on in our body. And one scientist told me that when you exercise, it' kind of like there's a chemical cocktail party going on up in your body. There's also dopamine, serotonin, adrenaline, and some other stuff, like, all dancing around in there.

[B]

Great.

[A]

Okay, so the last thing I want to talk about is if you haven't had runner's high and you Want to. What should you do?

[B]

Oh, yeah, yeah. Can you, like, make it more likely that you'll feel a runner's high?

[A]

Well, we don't have a ton of studies on how to get it specifically, but Michael did have some tips based on other studies about exercise and endocannabinoids. Okay, so first he said that you should aim for a heart rate that's between 70 to 80% of something called your age adjusted max heart rate.

[B]

But how generally, like, how hard is that?

[A]

It's pretty high intensity, like pretty vigorous, but not your max. You don't want to be going like, like your hardest.

[B]

That's helpful.

[A]

And that's zone three running for people who are familiar with zones.

[B]

Got it.

[A]

The other thing is that it probably won't happen if you're doing that bare minimum 10 minutes.

[B]

Oh, you have to be running for a while, which makes sense to me. I feel like I don't really hit it until it's been like a good 20 minutes at least.

[A]

Yeah, that's basically what Michael said, actually. He said you should be running at

[C]

least like 20 minutes. At 35 minutes, more or less, you're having the best mood results in the studies. And. Well, then it depends which is the best setting for you. For example, if you like to run in nature, then it should be like, in nature. If you like your favorite music, you should listen to your favorite music. If you like to run in groups all alone.

[A]

So that's where we're landing. Meryl, how do you feel about running now?

[B]

I'm excited to get back out there. Like, it's. It is such a good feeling. And I'm excited that as long as you don't ramp up too quickly, you'll be healthier overall if you run.

[A]

Oh, great.

[B]

Are you gonna run more? Are you running right now?

[A]

Yeah. I think this made me feel like, all right, like, I do wanna get back into doing it more regularly. And I think that, like the idea that, okay, I can just start with 10 minutes a day. It might not feel good to, like, my athletes athlete's ego, but it's what will keep me safe and consistent. Oh, and now I can get a fat ass too.

[B]

Yeah. That's what we really learned is that, like, fat asses equal healthy running.

[A]

Like, more so. Like a muscular ass, I guess. But either way, okay, I'm definitely gonna get back into it.

[B]

All right, nice.

[A]

Thanks, Meryl.

[B]

Thanks, aketti.

[A]

That's science versus. There are 76 citations in this week's episode. If you want to check them out, you can go to the link in our show notes. This episode was produced by Ekedi Foster Keys with help from Blythe Terrell, Michelle Deng, Rose Rimler, Meryl Horn and Wendy Zuckerman were edited by Blythe Turrell. Wendy Zuckerman is our Executive producer. Fact Checking by Taylor White Mix and sound design by Bobby Lord Music written by Bumi Hidaka, Peter Leonard, Emma Munger and Bobby Lord. Thanks to all the researchers we got in touch with for this episode, including Dr. Anita Eberle, Dr. Johannes Fuss, Professor Robert Otto, Dr. Hirofumi Tanaka, Dr. Peter Kokino, Dr. Marilyn Moffitt, and director Brian Farr. A big thanks to Joseph Lavelle Wilson and the Zuckerman family. Science Versus is a Spotify Studios original. Listen for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications. We'll catch you next week.