Today you’ll learn about how men with physically strenuous jobs have higher testosterone levels and, ahem, sperm counts, about how a researcher studying whales figured out an ancient mystery, and how providing women with more opportunities actually increases men’s life expectancy.
Today you’ll learn about how men with physically strenuous jobs have higher testosterone levels and, ahem, sperm counts, about how a researcher studying whales figured out an ancient mystery, and how providing women with more opportunities actually increases men’s life expectancy.
Men At Work
Whale Interrupted
Gender Equality
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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/men-at-work-whale-interrupted-gender-equality
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today you’ll learn about how men with physically strenuous jobs have higher testosterone levels and, ahem, sperm counts, about how a researcher studying whales figured out an ancient mystery, and about how providing women with more opportunities actually increases men’s life expectancy.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: WHOOSH]
CALLI: So a recent study at Harvard Medical School found that men with strenuous jobs actually have higher fertility rates.
NATE: Strenuous jobs like? I'm just going assume like podcasting, probably.
CALLI: Yeah, no, nothing like that. Sorry.
NATE: That's rough.
CALLI: These are jobs that involve heavy lifting, physical exertion and strenuous exercise. And not only that, they found that the same men also had higher testosterone levels than men whose jobs don't involve physical labor. The study found that men who reported doing heavy lifting at work had 46% higher sperm concentrations and 44% higher total sperm counts.
NATE: It sounds to me like this probably has something to do with the amount of exercise they're getting, right?
CALLI: Maybe. Let's take a look at why this study was conducted in the first place. It was conducted as part of a clinical study called EARTH, which stands for Environmental and Reproductive Health. It's actually a collaboration between the Harvard T.H. Chan School of Public Health and Mass General that was formed to study reproductive health through the lens of environmental chemicals and lifestyle choices. And the thing is, it's an incredibly important study because men's sperm counts and fertility rates have been in freefall for the last 50 years.
NATE: Oh, boy, are we headed for some Children of Men-type dystopian hellscape here?
CALLI: Not anytime soon, probably, But the facts are alarming. Some studies, including one by Dr. Shanna Swan, have shown a 50% drop in sperm counts in Western countries since the 1970s, and by some counts, testosterone levels are declining by up to 1% per year. But that's not all. The Earth study found that sperm counts in quality declined by up to 42% between 2000 and 2017 alone.
NATE: Testosterone, sperm and fertility. Oh, my. So what's going on here? You know, please refer to my previous question about a future dystopia.
CALLI: Right. So researchers don't know and that's kind of one of the reasons for the study. Are environmental chemicals causing this decline? Could it be lifestyle choices? Or maybe there's some broader public health issue like increasing levels of chronic disease, or is it all of the above?
NATE: But what you're really saying is that in order to save humanity, I need to go get a job as a firefighter or a lumberjack. Right.
CALLI: You had those just on hand?
NATE: No reason.
CALLI: Okay. Okay. Scientists already know that exercise correlates to better reproductive health.
NATE: Okay, so it's not the job. It's the exercise they're getting.
CALLI: Maybe. And here's another head scratcher for you. The EARTH study also found higher sperm counts and testosterone levels in men who work evening shifts compared with those who worked the day shifts.
NATE: What? All right, I. I got to say, I don't even have a theory for that one, honestly.
CALLI: Yeah, exactly. It's a little bit confusing. And that goes to show the intriguing nature of observational studies like this one. They can see trends, but it's difficult to understand causation. To make matters more complicated, many of the study's participants were men who were seeking treatment at a fertility center, which might mean that the results won't translate to the broader population. What they do know is that making healthier choices like watching what you eat and getting plenty of exercise will lead to better health, which will lead to.
NATE: Better reproductive health.
CALLI: Exactly. It could be that the real revelation here isn't that men who are physically demanding jobs have a higher sperm count. It's that men with sedentary jobs have a lower sperm count and testosterone levels.
NATE: Hmm. Well, I think I still kind of want to be a lumberjack.
CALLI: Right. You're really set on that one. Why not just go to the gym?
NATE: Or maybe a gym that has wood chopping instead of just lifting weights?
CALLI: Yeah. I think you're on to something
[SFX: WHOOSH]
NATE: Calli, tell me everything you know about the hafgufa.
CALLI:Okay. The hafgufa is. Is this real? Is this what? What is.
NATE: This? I'm so glad you asked. The Hafgufa was a rather mysterious sea creature described in some detail in a mid 13th century Old Norse text called The King's Mirror, which was a text used to explain the world to young people. What's really interesting here is that scientists discovered certain whale behaviors in the 2010s that were actually already described a millennia ago in this ancient text, proving that we still have more to learn from ancient documents.
CALLI: This is very cool. So what you're saying is that ancient Norse people saw these what we now know is whale behaviors and wrote about them as the hafgufa.
NATE: You could definitely see that in The King's Mirror. The writer describes the behavior of the hafgufa like this: When it goes to feed the big fish, keeps its mouth open for a time, no more or less wide than a large sound or fjord and unknowing and on heating the fish rush in. It goes on to say. And when its belly and mouth are full, it's the hafgufa closes its mouth, thus catching and hiding inside it all the prey.
CALLI: OK. That is oddly specific.
NATE: It is, isn't it? And it turns out that descriptions like this one have been found in texts as far back as a Greek manuscript called The Naturalist, compiled in Alexandria almost 2000 years ago.
CALLI: So are you telling me that we used to think that whales were kind of mythical creature like a chupacabra?
NATE: It seems that at the time, that might have been true. Yeah. A 1986 study of the King's Mirror couldn't figure out what this description was a reference to, and eventually just concluded that it must have been some kind of fantasy creature akin to the Kraken, which is another fabled sea monster.
CALLI: Okay, please tell me this is a story about how krakens really exist.
NATE: Maybe sort of, but not in the way I think you're hoping for. Fast forward to the Gulf of Thailand. In 2011, Bryde's whales were seen feeding like the creature from the Old Norse text. It was the first observation of this behavior. It hovered at the surface with its jaw wide open, and as soon as the fish swam in the jaw shut and off it went. It was an unknown technique that scientists called tread water feeding, and it had them befuddled.
CALLI: Did you just use the word befuddled?
NATE: I did. It's a good word.
CALLI: It's also. You've been reading too much Old Norse, maybe.
NATE: Anyway, a similar behavior was observed in humpback whales near Canada's Vancouver Island around the same time. Researchers there called it trap feeding. But no matter what they called it, scientists thought this reflected a sudden change in feeding behavior and couldn't figure it out. Why and how had these animals suddenly developed a new method for feeding?
CALLI: I can see where that would be a cause for concern, especially as like climate change is causing all these changes in migration patterns and animal behavior. We've we've talked about it a few times on the show.
NATE: Exactly the thought at the time that it was maybe due to a lack of oxygen in the water, which was causing the whales to have less energy and resort to a more passive feeding strategy. But Dr. John McCarthy, a maritime archeologist at Flinders University in Adelaide, South Australia, saw a video of whales trap feeding and about a year later picked up, You guessed it, an Old Norse text.
CALLI: Oh, hafgufa!
NATE: So the description from the King's Mirror and subsequently from other texts like the naturalist described in detail what appeared to be this exact feeding technique.
CALLI: So let me get this straight. Despite all of our technology, we've got submersibles, sonar, deep sea scans, not to mention are highly scientific study of whales and other marine mammals. We had never observed behavior that people witnessed hundreds or maybe even thousands of years ago.
NATE: We can never know for sure exactly what they saw back then, but the similarities are pretty convincing. So Dr. McCarthy put together a research team and published a study in the journal Marine Mammal Science. They concluded that while they can't be certain that the creatures described historically are the same species observed around the world in the past decade, the parallels are too striking to dismiss.
CALLI: Okay, so if the hafgufa is probably a whale, what's a kraken?
NATE: Sounds like the setup to a weird seafaring joke.
CALLI: Release the kraken!
[SFX: WHOOSH]
CALLI: Hey, mate, Do you want to live longer?
NATE: Yeah, sure. I guess that sounds good.
CALLI: Okay, cool. Well, it turns out all you need to do is empower women.
NATE: Cool. I'm all for it. I'm going to live forever. Mm hmm. Wait, what are you talking about?
CALLI: Okay. Glad you asked. A new study from the George Institute for Global Health in the UK has found that in societies where gender equality increases, so does the life expectancy for both women and men.
NATE: Wow. Okay, so let me get this straight. You have to treat men and women the same. In order for this to work.
CALLI: Weird, right? I mean, close, but not quite. In fact, gender equality does not mean treating men and women the same. The gender gap at its most basic is just the gap between the opportunities available to males versus those available to females.
NATE: Okay. So closing the gender gap just means giving women more opportunities.
CALLI: Basically, or at least more access to opportunities. The study used a modified gender gap index based on an index that was developed by the World Economic Forum in 2006 to assess gender gaps in countries all over the globe.
NATE: How do you measure gender gaps anyway?
CALLI: The original index included four basic areas of inequality, but the study only looked at three: economic, educational, political. Economics looked at things like how salaries compare or how women participate in the job market.
NATE: Okay. Right. So if women make up a large part of the workforce and get paid well, then the gap is smaller.
CALLI: Yup. And a smaller gap in education means that women and girls have more access to basic and higher education. And I bet you can guess what happens when there's a small gap in politics.
NATE: Madame President.
CALLI: Not just the presidency. In more equal societies, women have a seat at the table when it comes to making decisions at all levels.
NATE: Okay, so tell me how it is I’m going to live forever.
CALLI: Okay, well, roll it back to the study. Lead author Dr. Cat Pinho-Gomes wanted to publish in the lead up to International Women's Day because the findings were pretty remarkable. Overall, with a 10% increase in gender equality, life expectancy increased by 4.3 months for women, which you might expect, but it also increased by 3.5 months for men.
NATE: Okay, so let me get this straight. Giving women more opportunities in the economy, in education and in decision making actually made them Men live longer.
CALLI: You got it. And the increases in life expectancy for everyone were especially pronounced when women were given better access to education, especially in lower and middle income nations, where access to education isn't so great in the first place.
NATE: Okay, so what's going on here?
CALLI: So there's a lot of things that could be at work, but probably the most likely thing happening is a rising tide.
NATE: Okay. Rising tide lifts all ships.
CALLI: And when women who tend to have less opportunities in just about every nation on earth are given better access to education, then.
NATE: They get educated.
CALLI: And with more education.
NATE: More money.
CALLI: If half of your population's wealth increases, then the effect is a wealthier nation overall and wealthy nations tend to live longer.
NATE: Thus, a smaller gender gap means a higher life expectancy for everyone.
CALLI: Pretty cool, right? And what's even cooler is that a study like this can begin to influence policymaking by showing that making conditions more favorable for women can lead to a wealthier, healthier society for all of us.
NATE: As if giving women more opportunities wasn't reason enough on its own.
CALLI: Exactly.
[SFX: WHOOSH]
NATE: Let’s recap what we learned today to wrap up.
CALLI: Researchers have found that men with physically demanding jobs, specifically ones in which they have to frequently lift heavy objects, correlates to a higher sperm count and higher levels of testosterone than men whose jobs are not physically demanding. The study follows an alarming trend of decreased sperm counts in men over the last 50 years.
NATE: Scientists were puzzled when they observed a seemingly new feeding behavior in whales in multiple locations around the globe they called “trap feeding,” in which whales waited motionless at the surface of the water for fish to swim into their mouths. They struggled to explain the new technique until Dr. John McCarthy, a maritime archaeologist, happened to read an Old Norse text which described a marine beast employing a remarkably similar behavior. Coincidence? Or kraken?
CALLI: A recent study found that shrinking the gender gap by increasing opportunities in education, economics, and politics for women actually increased men’s life expectancy. Researchers believe that this is because when women have more opportunities, they tend to earn more. And a wealthier society is a healthier society, whether you were born a male or a female.