Stress ages us on a cellular level

It's no secret that stress isn't good for you… But just how bad is it? NPR's Short Wave podcast gets some answers. Host: Regina G. Barber, host of NPR’s Short Wave podcast Guest: Diana Kwon, science journalist Follow NPR's Short Wave podcast on Apple Podcasts and Spotify for more episodes like this, featuring new discoveries, everyday mysteries and the science behind the headlines. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. For show transcripts, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unxtranscripts⁠ ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠For more, go to ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/unexplainable⁠⁠ ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ And please email us! ⁠⁠⁠⁠⁠[email protected]⁠⁠ ⁠⁠⁠ We read every email. Support Unexplainable (and get ad-free episodes) by becoming a Vox Member today: ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠vox.com/members⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ Thank you! Learn more about your ad choices. Visit podcastchoices.com/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Noam Hassenfeld?

  Anyone who listens to Unexplainable knows that music is really important to me. So I want an amazing sound system. But I also want something that's easy. It just works. Sonos delivers on all fronts. The sound is incredible, and my Sonos system follows me wherever I go. I can mix and match speakers in any room in my apartment, louder in the living room, quieter in the kitchen. And the Sonos app makes it all super easy. Visit sonos.com and build your system. Sonos: Love the sound, feel the system.

• 0:37Speaker 01

  Are you a pet owner? Every six seconds, a pet owner in the US gets hit with a vet bill over $1,000. Always an unwelcome surprise. That's where Fetch comes in. Fetch is the most complete pet insurance for dogs and cats, according to consumeradvocate.org. You get paid back up to 90% of vet bills at any vet in the US and Canada, with claims paid back in as little as two days. Go to fetchpet.com/save right now for your free quote. That's fetchpet.com/save.

• 1:17Speaker 02

  This is Unexplainable. I'm Bird Pinkerton. And today on the show, I am very excited to bring you an episode of a show that I really enjoy, NPR'S Short Wave. I have been listening to Short Wave pretty much from the beginning. I find the show funny. I find the people on it friendly. I love how they tackle science news. And so they're going to tell us a story about stress, specifically about some research on how stress shows up in our bodies and what it might have to do with, quote unquote, zombie-like cells. So without further ado, here's the show.

• 1:58Speaker 02

  You're listening to Short Wave.

• 2:01Speaker 03

  From NPR. Hey, short waivers. I love my job, but I'm going to be honest, sometimes it's stressful. And when I'm stressed, I can definitely feel it in my body, which science journalist Diana Quan says makes sense.

• 2:16Speaker 04

  I've reported a lot of stories in the past about the biological effects of stress.

• 2:21Speaker 03

  Stress can really take a physical toll, but I don't think I realized just how much of a toll until this episode, when I called her to discuss the link between stress and aging. And she told me, yep, Gina, there's a whole body of research on this very topic.

• 2:37Speaker 04

  It just kind of made a lot of sense that stress sort of affects aging as well because, you know, things like various disorders and diseases, you know, these all affect how quickly we age.

• 2:47Speaker 03

  She told me about a study researchers did in the early 2000s, looking at stress in 58 biological mothers.

• 2:53Speaker 04

  About a third or a bit more than a third who had a healthy child and 2/3 who had a child with a chronic illness. And they kind of reasoned that this latter group would have higher levels of stress due to having to take care of somebody with an illness.

• 3:09Speaker 03

  Part of the study included asking those parents about their stress levels, which were higher for the caretakers of kids with an illness. But Diana says this study also did something pretty unique.

• 3:21Speaker 04

  It was one of the first studies to really bring the stress and aging link to like the molecular level.

• 3:27Speaker 03

  So more researchers started looking for signs of psychological stress in people's DNA.

• 3:32Speaker 04

  You know, not only did this group of people with a chronically ill child report having higher levels of stress, they also had shorter telomeres.

• 3:43Speaker 03

  Telomeres are the protective caps on the ends of chromosomes. And overall, their shortening is associated with aging. So more stressed parents with shorter telomeres equals biologically older parents.

• 3:55Speaker 03

  Since then, other studies have found other clues to how stress affects the body on the molecular level. They linked chronic stress to an increase in something called senescent, or zombie cells.

• 4:06Speaker 04

  As our cells age, they stop performing their regular functions and they enter this kind of sleepy zombie-like state.

• 4:15Speaker 03

  And they stop dividing, like normal cells do. Some researchers are starting to think that these zombie cells are sucking up resources from the rest of our body, which ultimately results in aging, and could ultimately help researchers answer the question:

• 4:30Speaker 04

  What is it about stress that's changing our cells that, you know, makes people become less healthy later in life?

• 4:38Speaker 03

  Today on the show, a new hypothesis for how the brain handles these aging zombie-like cells may help researchers understand aging on the molecular level. Plus, what science could do about it. I'm Regina Barber, and you're listening to Short Wave, the science podcast from NPR.

• 5:02Noam Hassenfeld?

  Support for the show comes from Sonos. Hey, Sonos, give me some music.

• 5:08Noam Hassenfeld?

  All right, one of life's great mysteries. You're listening to music in the living room, but you gotta grab something from the kitchen. You don't want to take the speaker with you, but you also don't want to miss that beat drop. And this is where I introduce you to the magic of Sonos. Sonos sent me a couple of speakers to try out, so I've got to move two here in the living room. And then I walk down the hall.

• 5:33Noam Hassenfeld?

  I get in here to the kitchen, and I got a brand-new Sonos Play right here on the counter.

• 5:41Noam Hassenfeld?

  I can open the fridge, grab a seltzer.

• 5:50Noam Hassenfeld?

  And yeah, I didn't miss a second. And I can make each speaker louder or softer in the Sonos app, or if I'm using AirPlay, so I can make it louder in the kitchen without blasting whoever is still in the living room. It's all just easy and it sounds amazing. These speakers are crisp. They've got great bass. And I'm especially impressed with the new Sonos Play. It packs this like truly awesome sound in a much smaller size. So I don't know if I want to head outside for a minute. It's super easy and yeah, pretty nice out. Visit sonos.com and build your system.

• 6:34Noam Hassenfeld?

  Sonos, love the sound, feel the system.

• 6:42Speaker 02

  Support for the show comes from TikTok. Being curious is endlessly rewarding. There are few better feelings, in my opinion, than asking a question and then having that question lead you down a rabbit hole. Might even be the beginning of a new set of interests that was not on your radar beforehand. Maybe you're looking up at the night sky one night and you start to wonder what the most distant thing you can see with a naked eye is. One place to start searching for answers to a question like that is TikTok. First, you might discover a video about the Andromeda Galaxy. And then, next thing you know, you're learning how to find different stars, or how to identify constellations,

• 7:26Speaker 02

  or how different astronomical discoveries got made, or how constellations got their names. You don't need serious equipment to make serious discoveries. To start with a simple question, and suddenly you're somewhere you never expected to be. Your next discovery is waiting on TikTok. Learn more at tiktok.com/discovermore. At tiktok.com/discovermore.

• 7:57Speaker 05

  Ask yourself, what are your best people spending their time on right now? Expense reports, receipt chasing, month-end close that takes weeks. You've become what you spend on, and that's not what you're building toward. Brex is the intelligent finance platform that eliminates that work before it starts. AI agents that handle the manual stuff automatically so your team can spend their time on what actually compounds. It's time to get Brex AF. Learn more at brex.com/AF.

• 8:34Speaker 03

  Okay, Diana, so these researchers that are like studying aging, they've developed this hypothesis called the brain-body-energy conservation model. As a physicist, I love any energy conservation model, actually. How does this work?

• 8:47Speaker 04

  Yeah, yeah, so this is a really interesting model developed by, you know, a small group of aging researchers. So it's by no means a well-established, widely-accepted model yet, but basically, as our cells get older, you know, they accumulate energetically costly forms of damage. So these are things like becoming zombie-like, or senescent, or accumulating DNA damage, or inflammation, you know, all of these things are-

• 9:17Speaker 03

  Those telomeres shortening.

• 9:19Speaker 04

  Exactly, so all of these things require energy to fix. And so the brain, through, you know, various signaling molecules that are coming through the body, senses that, okay, there's a bunch of cells out there that need energy, and so we're going to take energy away from other processes to fuel this damage control. And so this ultimately results in the outward signs of aging that we're all familiar with, things like growing hair, or reduction in muscle mass, that are less essential than keeping our cells alive.

• 9:51Speaker 03

  Yeah, it makes me think of like how older appliances, like fridges, you like use more energy, they're less energy-efficient, like than the newer ones that are like running well, you know?

• 10:00Speaker 04

  Yeah.

• 10:00Speaker 03

  So in your piece, you write about an experiment these researchers did- Uh, the ones who came up with this model a couple of years back to look at how these zombie cells use energy. Can you tell me more about that?

• 10:11Speaker 04

  Yeah, so this was back in, I think, 2022, where a bunch of researchers at Columbia took human skin cells and cultured them in a laboratory dish. And they observed them over a short period of time, and they found that the cells that had stopped dividing and entered this zombie-like state were using about double the energy that younger cells were. And this kind of flew in the face of what researchers had thought about these zombie cells, because, you know, a lot of people thought, OK, a cell doesn't divide anymore. Cell division requires a lot of energy. You know, these cells must not, must not need a lot of energy. But actually, it turns out that they're burning a lot of energy. And so, you know, the researchers went and kind of looked at the

• 10:55Speaker 04

  literature and found, oh, wait, there's like all of these other damage processes that are happening, and these are all costly. You know, we should put this into a model. And, you know, the brain-body energy conservation model is what they came up with.

• 11:07Speaker 03

  And this is a pretty new hypothesis, right? Like, the entire aging research community isn't completely convinced yet, right?

• 11:16Speaker 04

  Yeah, it's absolutely a new hypothesis. They only came up with it, you know, in the last couple of years. And the researchers I spoke to who hadn't developed this hypothesis, a lot of people thought it was really intriguing. And I think what a lot of people like about it is that it kind of brings the brain and body together in aging. And that's something that hasn't really been done before, this kind of unified hypothesis of aging. One can kind of think of it in that way. But, you know, in a lot of ways, a lot of pieces of this puzzle are untested, even though there are some really compelling hints or pieces of evidence that, you know, this might actually be happening.

• 11:55Speaker 03

  Right. Yet, one of these things that has come up in these studies is this molecule called GDF-15. Why is this important in this research?

• 12:04Speaker 04

  Yeah, so GDF-15, or Growth Differentiation Factor 15, which is a bit of a mouthful. So, I think this was one of the most fascinating pieces of the brain-body aging model puzzle. So basically, GDF-15 is a cellular messenger, and

• 12:25Speaker 04

  Researchers think it might play a really central role in mediating the link between the body and brain and aging. And this molecule has also come up in aging research, sort of not related to the brain either. So it's been linked to a bunch of different aging-related processes. Once again, cellular senescence or a zombie-like state. So you know, the, this molecule is found to be linked to that process. Also a dysfunction in mitochondria or the cellular powerhouses. This is also something that happens as we age. GDF-15 is also linked to aging-related diseases like Alzheimer's and a bunch of chronic physical and mental illnesses too. And so, one thing that's really interesting about this molecule is that it's secreted

• 13:09Speaker 04

  by many, if not all of our organs, but the receptor for this molecule is only found in one place in the body, and that's in the brain. And so, you know, all of these things together, yeah, have made researchers think, okay, maybe GDF-15 is responsible for sending the brain's signals about cellular stress. So this is kind of a working hypothesis at the moment, but a really fascinating molecule that might play a really important role or be a really important piece of this whole puzzle.

• 13:39Speaker 03

  There are so many unknowns still, but scientists are already trying to create medicines, like to slow down aging. So with this new hypothesis, how are scientists going to maybe think differently about clinical trials?

• 13:51Speaker 04

  Yeah, I think both of this new hypothesis and the kind of growing body of research that shows that stress plays a really important role in these aging-related processes. What a lot of the stress researchers or the stress and aging researchers that I spoke to said is that, you know, this field of aging, which traditionally hasn't really thought about the effects of stress, should really think about how much stress the people who are taking these drugs or, you know, will be taking these drugs in the future are exposed to because that might have a huge impact on how well these interventions work.

• 14:24Speaker 03

  When you were doing this story, at the very end, when you've done all this reporting, did you come away thinking differently about aging, about stress?

• 14:33Speaker 04

  I guess yes and no. No in that, you know, I wasn't necessarily surprised that stress, which affects so many parts of our body, affects aging as well. But I guess yes, in that for such a long time, it was kind of this like woo woo connection. Oh, you know, stress causes aging, but you know, how without a mechanism? So I thought it was really cool that this research is seems to be entering a kind of new era where, you know, hopefully it'll start to make a big difference in people's lives.

• 15:02Speaker 03

  Yeah, I mean, this actually does make me feel like more hopeful as well about stress and aging.

• 15:07Speaker 04

  Yeah, absolutely. And that makes me think of, you know, there's actually been some experiments where scientists have found that some of these stress-related aging changes in our cells are reversible. So there were researchers who did a study in monkeys where they found that monkeys that were stressed out had these changes in their immune cells that were linked to accelerated aging. But they found that when they switched up their conditions and put them in less stressful situations, you know, all of a sudden the cells bore less or reduced signs of accelerated aging. So I think that's a really positive thing because I think the this kind of stress may be linked to aging or cause aging at some level. It can be a really negative message and it can stress people out to think that

• 15:50Speaker 04

  stress is going to age you because, you know, stress is one of these things.

• 15:53Speaker 03

  You're stressed because you're stressed about stress.

• 15:55Speaker 04

  Exactly.

• 15:56Speaker 03

  Yeah.

• 15:56Speaker 04

  But no, these changes are not irreversible. These are things that, you know, we can affect in our daily lives to some extent. It's it's kind of more hopeful in my view. It's a hopeful view of the future where we will have a toolbox of things that may help us stay healthy for for longer.

• 16:13Speaker 03

  Yeah, and less stressed.

• 16:15Speaker 04

  Yeah.

• 16:17Speaker 03

  Diana, thank you so much for talking to me today about aging. It makes me think about aging, you know, more because I always think about it.

• 16:25Speaker 04

  Don't we all? Thanks so much for having me.

• 16:29Speaker 03

  Shortwavers, thank you for listening. If you want to help us out, share this episode with a friend. We want to grow as we age and reach even more science curious people. And that's one of the best ways to do it, by word of mouth, from you to your friends. And why not follow us on the NPR app or whatever other podcast app you use. This episode was produced by Burley McCoy, edited by showrunner Rebecca Ramirez, and fact checked by Tyler Jones. The audio engineer was Jimmy Keely. Beth Donovan is our senior director and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Short Wave from NPR.

• 17:16Noam Hassenfeld?

  Support for the show comes from Sonos. No matter how much you know about frequency response or harmonic distortion, the thing that's going to make you fall in love with a speaker is how it makes you feel. And Sonos has that it factor, you know? It's this seamless system that makes things sound good in every room. That obviously takes some serious engineering, but it also takes a big picture understanding of how and why we actually listen to things. The birthday playlist, the new TV show, the exciting new game you just got. And for the nerds out there, Sonos does have amazing frequency response and extremely low harmonic distortion. Visit sonos.com and build your system. Sonos, love the sound, feel the system.

• 18:06Speaker 06

  Support for today's episode comes from Delta, official airline of the National Women's Soccer League. Traveling is basically magic. It creates opportunities, it fosters understanding, it expands horizons, it connects people and communities to each other and to their own potential. Those are the values that drive Delta. With up to 5,500 daily Delta and Delta Connection flights to more than 300 destinations on six continents, Delta is committed to helping you explore your world. Whatever gives you the travel bug, Delta is here to help you get there. Visit delta.com for more info. Delta, wherever the journey takes you.