Instant Genius - How working too hard is damaging your health and productivity

Episode Date: July 10, 2025

Be it at school or in the workplace, many of us are under more and more pressure to work harder for longer to ensure that we’re performing at our best. But the latest neuroscience research is discovering that we may all have this idea entirely the wrong way around. In this episode, we speak to neuroscientist Dr Joseph Jebelli to talk about his latest book The Brain at Rest: Why Doing Nothing Can Change Your Life. He tells us how overwork is leading to almost 750,000 deaths a year globally, how taking a few minutes to pause and do nothing every now and then can switch on the powerful effect of our brains’ default network, and how simply allowing our minds to wander from time to time can help us to be more creative and more productive. To get the exclusive gift box from Shokz, order via this link: ⁠https://bit.ly/4kFt10l⁠ Learn more about your ad choices. Visit podcastchoices.com/adchoices

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Be it at school or in the workplace, many of us are under more and more pressure to work harder for longer to ensure that we're performing at our best. But the latest neuroscience research is discovering that we may all have this idea entirely the wrong way around. In this episode, we speak to neuroscientist Dr Joseph Javelli to talk about his latest book, The Brain at Rest, Why Doing Nothing Can Change Your Life. He tells us how overwork is leading to almost 750,000 deaths a year globally,

how taking a few minutes to pause and do nothing every now and then can switch on the powerful effects of our brain's default network and how simply allowing our minds to wonder from time to time can help us to be more creative and more productive. So welcome to the podcast. Thanks very much for joining us. Thank you for having me. So today we're talking about your book, The Brain at Rest, why doing nothing can change your life. So that's quite a provocative tie. So what's the overarching theme of the book? So the overarching theme of the book is that we have our understanding of rest from the brain's point of view completely wrong. So when you rest, your brain doesn't shut down.

It doesn't switch off. It doesn't do nothing. It just switches state. It moves into what neuroscientists call the resting state, otherwise known as the default network. This is a network in your brain that fans out across your brain. becomes active when you rest. And so what do I mean by rest? Well, basically, rest is anything where you're stepping away from a mentally exerting task. So anything where you're not working, essentially, and that can be anything that you find particularly restful, like walking in the woods, gazing out of a window to mind wander, having a 30-minute nap, all of these things will activate

your brain's default network. And the really interesting thing is that neuroscience over the last 10 to 20 years has shown that when your brain's resting, when you're not working, it's actually more active than when you're working. It's more active than when you're focused on a task. And not only is it more active, but all of these incredible cognitive skills, like intelligence, like memory, like problem solving, creativity, even things like social empathy, emotional processing, they're all improved by resting the brain, by stepping away from work. And so the overarching premise of the book is that your brain is actually doing a lot of something when you seemingly do nothing.

And we need to take this a lot more seriously than we currently do, because in our current climate of just untrammeled capitalism and overwork and burnout, we're completely ignoring the resting brain. And we're losing all of these cognitive benefits as a result. And, you know, as I say in the book, things are only getting worse in this regard. So 745,000 people a year now die as a result of overwork. Three and five employees now report a lack of interest, motivation, and energy. And the crucial point is that this is an increase.

So, you know, the figure of overwork leading to deaths is actually, I think it's a 29% increase since 2000. And the data on employees' lack of interest, motivation, energy is a 38% increase since 2019. So even though working conditions are better than they are in the past, the fact is we are in a dramatic regression in terms of burnout and overwork. And I think lots of people understand that now. And so what I'm trying to convey in the book, and I interviewed lots of different people in the book, spoke to lots of different people in different industries, and I explore the default network in detail, is that actually, from your brain's perspective, rest is really, really crucial. It's far more crucial than we've ever imagined.

So say someone is overworked, what's actually happening in their brains and how does that affect their health? Yes, that's a really good question. So overwork does a lot of really bad things to the brain. One of the main things that we know that it does is that it actually thins the frontal cortex in the same way that aging does. So it literally makes the brain older than it is. And the way it does this is that it actually starts to prune back these things called dendrites, which are the branch-like structures on our neurons, on our brain cells. And once you lose those, those are really hard to recover.

The problem is as well, by thinning the frontal cortex, that's actually the region of your brain that's responsible for things like good judgment and an awareness of long-term consequences. So it's actually the only brain region that could advise a person against working too hard. But as well as that, overwork we now know leads to burnout and leads to death. It leads to early death. So the Japanese even have a word for this. They call it Karoshi, which means working to death.

And in Japan, it's estimated that there are 20,000 deaths a year from Karoshi. So this really is. I describe it in the book as the work pandemic, and it's a pandemic that's basically quietly being ignored by governments everywhere. But Overwork does, it does so many negative things to the brain, as well as thinning the cortex. It shrinks your hippocampus. That's a region crucial for learning and memory. It enlarges the amygdala.

that's a region associated with our fight and flight response. So that's why when you're overworked, you know, you feel really anxious, you feel alert, you feel like there's some sort of panic, you constantly feel troubled. That's because it's enlarging your amygdala. And there are deeper sort of cellular and molecular problems with overwork that we're only just beginning to understand. But I should also say that one of the key things I discuss in the book is that when you're working, your brain uses what we call the executive network. That's basically the work network. That's

the network the brain uses when there's like a job to be done. And the problem is we've become so enamored with this network. It's been the kind of hero in our productivity narrative that we've overused it. We've overtaxed it. And but the thing is, when you use your executive network, your rest network, the default network, is actually very quiet. They work in competition with each other. As I say in the book, it's a bit like having a neighbour's Wi-Fi signal, blocking out your own signal. But the default network actually occupies 20% of the brain. It's much larger in the brain than we ever thought before. And as I said, it's involved in all of these really crucial cognitive benefits.

And all of the data now, and there's a mountain of it, shows that whether you're a doctor, a train driver, a student, no matter who you are, you will perform better on a task if you rest. before that task, and that's precisely because you're activating your default network. So we really need to move away from this idea of just constantly activating our executive network, constantly activating our work network, this idea that if we work harder and harder and harder that will achieve more, when the complete opposite is true, it's all about stepping away from work and having prolonged periods of rest. That is the key to not only brain health, but long-term productivity. So let's have a look at some ways in which we can activate our default network then. You know, what sort of techniques can we employ?

Yeah, so there's lots of tools and techniques to activate your default network, which I'll explore in the book. So the first thing to say is the really interesting and wonderful thing about the default network is that it's kind of an all-or-nothing phenomenon. So when you activate your default network with rest, a region of the default network will start lighting up. It will start firing all of these wonderful, you know, neurochemical, electrical signals that help you in so many different ways. But when that happens, the rest of

the network almost always activates at the same time. It activates in unison. So what that means is that whatever you find restful, you know, whether that's a walk through the park or just gazing out of the window, letting your mind wander, you know, having a nap, going on a jog, having some active rest, you know, even playing, you know, video games for a show, short period of time. Like if whatever you find restful will activate some part of your default network and that will then most likely activate the rest of your default network as well, that will then give you all the cognitive benefits of activating your brain's default network. You know, I explore lots of different techniques in the book. And I mean, one of my favorites is

the half an hour nap, for instance. So there's really fascinating research done at UCL by Victoria Garfield in 2023 showed that nappers, people who take 30 minute naps every day actually have larger brains than people who don't. And the difference is really significant. We're talking the volume of a small plum. And so, you know, when I tell people that, I say to them, you know, just pause for a minute and think about all of the neurons and synapses that are contained in the volume of a small plum. It's huge. All of that cognitive potential that we're missing out on by not having that crucial 30-minute nap. And that research also showed that in addition to, you know, actually making your brain much beefier, much chunkier, it actually delays brain aging by up to six

years. So the 30-minute nap every day is something I'm now desperately trying to do every day. But as well as things like walking in nature, for instance, that's like a really, really good one to activate the default network. So as well as like the physiological benefits of walking in nature, for instance, when you walk in nature, you're exposed to these plant chemicals called fightensides, and they're essentially natural oils that protect trees from bacteria, but we now know that they have a really positive effect on our immune system, and that even if you, say, one of my favourite studies showed that if you spend three days camping, it can boost your immune system by 40% and that lasts over a month

because of the fight and side exposure. But in terms of the default network, we know that spending time in green spaces and in nature improves your creativity and problem-solving abilities by up to 50%. It can then also improve your memory recall by as much as 20%. And it's really interesting. In terms of the mechanisms as to how this works, we think it's to do with what psychologists call soft fascinations. So these are things that hold your attention in a very effortless and relaxing way.

So I'm sure you've noticed that when you go out into nature and you just look up at the trees, you sit on a bench, and you know you're by the beach and you're just listening to the lapping of the waves. All of that, it holds your attention, but it feels effortless. And it feels effortless because it's having a really profoundly positive impact on your brain. So one of the main things it does is it will change your brain waves. It will change them from very busy and anxious beta waves to much more daydreaming and creative alpha waves and even meditative theta waves.

And so that's your default network coming alive. If that's your resting brain saying, you know, finally I've got a break from, you know, all of this artificial light and all of this really negative stuff to do with our chronic urban existence. And now I can actually process things and think about things and be creative in the way that I couldn't be when I wasn't doing this. Because the opposite of soft fascinations in nature is what we call hard fascinations. And these are things like smartphone alerts, social media, emails, bosses, you know, ridiculous deadlines. And all of those lead to cognitive overload and cognitive fatigue. There are so many different ways to activate the default network. I have a few of my favourite of things like spending time outdoors and napping,

but there's all sorts of things like mind-wondering exercise, finding play, finding micro-moments of play throughout your day, has also been shown to be really good for your default network. But as I said at the start, the really interesting thing is that it's whatever you find restful, because it will nearly always activate the rest of the default network as well. Wishing you could be there live for the big game, soaking up the atmosphere in a crowd. But too often, life gets busy, or the price holds you back. Price line is here to help you make it happen.

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Or capture sun-kissed bliss with limonada gelada. The nasty Brazilian Lemonade Accord meets coconut milk and golden brown sugar. Don't miss Sol de Janeiro's limited edition perfume mist collection, only at Sephora. This podcast is sponsored by Name, Audio and Focal. With over 100 years of combined expertise, Name and Focal have been bringing music to listeners just as the artist intended. Since day one, this mantra has shaped every innovation in high-fi design, technology, and acoustic engineering, balancing craftsmanship and tradition with pioneering thinking.

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always daydreaming, always got their head in the clowns. But now we're finding out that's not the case at all. Yeah, absolutely. So the funny thing is, all of the latest neuroscience now shows that basically everything you were discouraged from doing as a kid, so daydreaming, mind wandering, having your heads in the clouds, taking a nap in the day, all of that is wrong, basically, as in all of that is actually really, really good for the brain, and we shouldn't be discouraged from it at all. So there's two things to say about this. The first is just to briefly discuss the really profound and positive influence that mind wandering has on the brain. So mind wandering is really interesting because we actually spent

25 to 50% of our waking lives doing it. We spent a lot more of our day doing it than we even aware. All of the studies on mind wandering show something really interesting. So when you take a group of people and you ask them to perform a repetitive task, like a work-orientated, cognitively demanding task, the people who are allowed to mind-wonder almost always perform better on that task, precisely because they're engaging their brain's default network. They're engaging their resting brain. And this will then lead to an increase in creativity as well. So there's all these really interesting studies

where they'll take like a hard scientific problem, a hard mathematical problem, a hard engineering problem, and they'll have a group of people who just work relentlessly on it, you know, to the point of exhaustion. And it doesn't matter how hard they work on it, they will perform no way near as well as the other group who are told,

you know what, just go and chill out for a bit. take 45 minutes, go for a walk in the park, just relax, do what you want, do something that feels like you're doing nothing. Those people always perform better on the task because their brain's default network is busy churning through all of the different computations it needs to churn through. It's interesting in terms of how mind-wondering does this, but in terms of, you know, our culture of being told not to mind-wonder, I talk a little bit about that in the book. I think it's essentially because there's two things. We've essentially been tricked by untrammeled capitalism into thinking that if you're not doing something, if you're not working, you're doing nothing.

And that's bad. And that's just completely false. It's utterly false. And we've also basically been told basically since the Protestant work ethic of like the 16th century that, you know, the harder you work, the faster you run, the quicker you'll go. And all of the neuroscience shows that complete opposite is true. So you also talk about this, this is a new one on me, this Dutch concept. Sorry if I'm pronouncing it incorrectly, but Nitzing, what's the idea behind that? Yeah, so Nixon's really interesting. So Nixon is, it's a Dutch concept. It's a word that literally means doing nothing or doing nothing in. And it's essentially about finding the moments in between things. So what I mean by that, it's about saying to yourself, okay,

I'm going to go and sit down on the sofa, drink some tea and just stare out of the window. I'm going to find a few minutes of intentional rest throughout my day to actually allow my brain to rest. And so it's something that the Dutch are getting very good at. And in the book, I spoke to Olga Mecking, and she's written a wonderful book about Nixon. And I spoke to her about all the ways that she employs it in her day. And, you know, the interesting thing is, you know, she has three children, she has a full, time job. She's really busy. And yet she still makes time for Nixon, for doing nothing, for intentional rest. And this isn't another message I want to get across to the public with this book.

You know, lots of people say to me, I don't have time to rest more. And I understand that. I totally understand that. But the idea that rest is at loggerheads with modern life, I think is untrue and it's a dangerous falsehood. Because it really is crucial for our brains to find these moments to rest, to activate at our default network, not just for our brain health, but for long-term productivity, for long-term flourishing. And so Nixon is really useful because it's all about intentional rest. It's all about saying, no, actually, I am going to spend a few minutes stepping out of the office and just going on a walk and letting my mind wander. And, you know, it's a philosophy that I think, you know, we could really do it with a lot more of here,

certainly. So how about another thing? So exercise, which you mentioned earlier. So similarly, a lot of people say, well, you know, I'd love to, but I don't have enough time or energy to exercise, you know, but we don't have to run 10K or do hour long sort of weight sessions in the gym to get many of the benefits. Yeah, absolutely. So one of the most exciting findings in recent years is that you don't need to do excessive exercise to improve your brain health. So incredibly, even just 25 minutes of exercise a week, which is less than four, minutes a day has been shown to actually allow you to grow a bigger brain. It's been one of the most surprising and extraordinary findings of neuroscience in the last few years. Obviously, you should try and

exercise more than four minutes a day if you can. You know, I'm a firm advocate of the World Health Organization's recommendation of 30 minutes of, you know, active aerobic exercise a day, because obviously that will have huge impacts on your cardiovascular health. And we know that a health, and we know that a healthy heart equals a healthy brain. But the really interesting thing about it is that it just shows the extraordinary power of exercise, of active rest, and the power it can have on the brain. And the reason most likely we're still working on it that only four minutes a day has such a profound impact on the brain that can actually make it chunkier, is because when you exercise, your brain, your brain is flooded by these really valuable proteins. And one of them is the

protein called brain-derived neurotrophic factor, BDNF. And BDNF is a really interesting molecule. So many people in the Alzheimer's research community are really interested in BDNF because we know that BDNF really helps neurons not just survive, but thrive. It helps them grow their axons, grow their synapses, strengthen the connections between each other. And we know that BDNF can even slow the progression of Alzheimer's disease. So we think that, we think that, you know, But essentially allowing more of your brain to be flooded with BDNF and other really valuable proteins as a result of exercise, that's actually what's beefing up your brain. It's essentially acting as fertilizer on a garden. So another thing that's really commonly spoke about today is work-life balance.

So you mentioned earlier there the benefits of play or having a bit of fun. And people might be, well, that's too frivolous. I haven't got time to do that. I'm a very busy person at work. like you say, I've got children to look after, etc. So what benefits can, you know, taking a bit of time to have a bit of fun, a bit of play have? Yeah, that's a great question. So, I mean, I totally, of course, understand people's frustrations.

That's largely the result of the current economic system that we live in. And, you know, lots of people I spoke to you did say, you know, I would, you know, I really value rest. I want to have more time to rest, but I'm just too busy. And, you know, the first thing to say to that is, I understand that, but your long-term productivity is going to be improved by you having more intentional rest. So you're working very hard now and that's okay for your short-term productivity, but it's not good for your truly sustainable long-term productivity. So it really is a question of something that we have to do. We have to spend more time resting. People must be allowed to

work at home and to have far more breaks throughout the day. It's critical that we move to the four-day work week. I mean, you know, a huge trial in Iceland looked at this and they found that productivity either stayed the same or went up. So the fact is, you know, we're still essentially, we're still brainwashed essentially by untrammeled capitalism and this idea that work is the key to productivity and success and it's not. It's really not. It's actually quite damaging to productivity and success. And so, you know, when you share the science of the default network and the resting brain with people, then they start to think. a bit more about it and think, okay, I need to have more intentional rest. I need to essentially

incorporate this more into my life. But obviously a lot of this will come down to the employers as well. So, you know, I say to people who own companies, you know, it's really about allowing your workers to have, you know, tailored rest and personalized time off. And that that is the thing that will allow you to get the best from your workers because they'll have a healthier default network, a healthier resting brain, and there'll be far better at solving problems in the workplace for you. I mean, it's a tricky one because you can understand why people say it. And, you know, as I said, I think just sharing scientific benefits of it is really key. And you mentioned play. I mean, play's really interesting. So there's a whole field now dedicated to the neuroscience

of play, and scientists essentially break it down into four different categories of play. And So there's what we call other directed play where you're sort of playing with others. There's lighthearted play, which is kind of more random on the spot antics. There's what we call intellectual play, things like solving crosswords and cracking Suducus and things. And then there's like the whimsical play where you're just doing something very odd and unusual. But all of these things have been shown to be really good for the brain and for your creativity. And so we need to incorporate this more into our day to day. And so I think a part of it is also a

just allowing people to not take themselves and their work quite so seriously. I sort of hesitate to say it, but it's true. Like, you're not being frivolous by doing that. You're not being unserious. You're not, you're not doing something that's bad for your work by doing that. You're doing something that's really good for your brain, which is then really good for your work in the long run. So we've covered quite a lot there. So sort of, in summary, rather than, you know, buying the book and reading it for themselves, what sort of message would you like our listeners to leave with. So the message I'd really like read it to take away from the conversation is that it is rest, not working harder, that it's the secret to sustained productivity, and that if you can understand

your own default network, what it is, why it's so important, and all the different ways you can activate it, you will live a far healthier, far more successful life. As I say in the book, doing nothing may just be the most productive thing you can do. Thank you for listening to this episode of Instant Genius, brought to you from the team behind BBC Science Fakers. That was Dr Joseph Chubilly. To discover more about the topics we've just discussed, check out his book, The Brain at Rest, Why Doing Nothing Can Change Your Life. If you liked what you just heard, then please do consider subscribing to Instant Genius on your preferred podcast platform.

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