Jen: Welcome to the So That's Why podcast, where we unpack the
science behind everyday questions.
I'm Jen.
Jamie: I'm Chris.
And I'm Jamie.
Jen: Right, here's something that sounds completely back to
front when you first hear it.
Stress on its own isn't what makes us ill.
So a little bit of stress is genuinely good for you.
I know I need a bit of stress sometimes to help me complete those deadlines.
But- Why can stress make us ill?
Because a system that's brilliant in short bursts becomes a problem
when it never gets switched off.
Jamie: That's mildly irritating to hear, if I'm honest.
I spent years blaming stress for everything, bad mood, lost keys, the lot.
Now you're telling me it was on my side the whole time?
Jen: Yeah.
Well- But I think I'll carry on blaming it.
Chris: Yeah.
It's on your side in the right dose, I think, I think it's fair to say.
So if it's the nerves before a big presentation that sharpen you up, or,
you know, the push before a deadline that gets you focused, those types
of stress can be really helpful.
And in fact, there's even a name for it.
It's called
Jen: eustress.
Which I am definitely gonna use that phrase in an argument.
I'm not stressed, I'm eustressed.
Of
Chris: course, the trouble is, um, like most of us aren't living in these kind of
short bursts of stress anymore, are we?
It's kind of chronic stress normally.
Jen: Yeah.
Jamie: So how big is the problem?
Jen: Okay.
Well, we love our facts on this podcast, don't we- … and our research.
So there was a survey of more than 145,000 adults in 144 countries, and they found
that 37% had felt significant stress the day before they did the survey,
and 39% experienced serious worry.
And every one of those measures, stress, worry, sadness, is
higher than a decade ago.
Jamie: More than one in three people on an ordinary day, not a
crisis week, just an ordinary day.
Chris: I know.
Jen: I've got to say- I know.
It's huge.
Yeah.
It's really… It's sad, isn't it?
Chris: Yeah.
You did well to remember all those, uh, stats in one go as well.
I mean, totally got them the wrong way around.
Um, but the thing is, those stats, they add up, don't they?
They stack up because the World Health Organization now counts
over a billion people as living with a mental health condition.
Um, so rates anxiety and depression, which are both tangled up with
stress, as the second-biggest cause of long-term disability worldwide.
Jen: That's huge, isn't it?
Yeah.
Absolutely huge.
And, you know, the picture in the UK is just as stark,
so some more figures for you.
Across '24 and 2025, 964,000 workers were dealing with work-related
stress, anxiety, or depression.
And here's what is interesting.
The year before, it was 776,000, so that's the sharpest single-year jump
on record, and it actually costs the economy around 22 million working days.
Matt: Wow.
Jamie: 964,000 people.
That's a city worth of workers signed off.
And the real-life figure's probably higher because plenty of people
just, just push through it.
Jen: Yeah.
I think that's a really helpful comparison, that it's a city worth.
It gives people a bit of a-
Chris: No, definitely,
Jen: yeah … a picture, isn't it?
Chris: Yeah.
And you're right, Jamie, it's almost certainly gonna be higher, isn't it?
For, for sure.
Um, so around 80% of UK workers say they feel stressed regularly, which
is no surprise, and statistics suggest that stress-related absences from
work are up by over a third since 2020
Jen: I think, I'll be honest, my first instinct reading those was to feel
stressed about how stressed everyone is, which obviously helps nobody.
Chris: Absolutely.
And that's exactly why understanding the mechanism matters more than anything else.
So shall we get into what's actually happening in the body?
Jamie: Please do, because to me, stress has always been
just a sort of vague concept.
So what exactly is happening in your body when you're stressed?
Chris: So when the brain decides there's a threat, whether it's, um, real or
imagined, it fires up two systems.
So the first is a fast one that floods your, well, floods you with adrenaline,
so your heart rate speeds up, your blood pressure rises, and sugar pours into the
blood to get energy to your muscles fast.
Jen: Yeah, which obviously sounds like a good system.
Your body needs that.
But then after that, a slower one follows, and that releases cortisol,
which is the main stress hormone.
We've chatted about it in different episodes.
So cortisol keeps your energy topped up, and to do it, it quietly turns
down anything you don't need in an emergency, like digestion, repair, and
even a chunk of your immune system.
Jamie: So if you were to picture it like a kitchen, you get a text that guests
are arriving at the door in five minutes.
Mm. Everything urgent gets done immediately.
The gas goes on, the hob's on full.
That's the adrenaline, the heart racing, energy flooding your
body to deal with the threat.
And everything that can be is dropped, the washing up, the post
on the mat, the laying the, putting flowers in vases on the table.
That's your digestion and your immune system being put on hold.
All the effort goes into the emergency, none to the upkeep.
Jen: Yeah.
Chris: That's a very passionate analogy.
I'm, I'm assuming you've had some kind of house party
recently- I just love my cooking
… Jen: that got you quite stressed about it.
I love the flowers on the vase as
Chris: well.
I know, definitely.
Um, but the thing is, when it comes to these kind of short scrambles of, of
stress, your body really is brilliant at coping with that short scramble.
So back to Jamie's analogy, the hope is that the guests
actually leave at some point.
So once you've kicked everybody out and done the washing up, you can
have a little sit down and a relax.
The heart rate settles, digestion comes back to normal, and everything resets.
Jen: But coming back to stress, the problem is the version where the guests
never leave, so the hobs stay on full day after day, and that upkeep never happens.
The post piles up, the washing up festers, and the kitchen, after
a while it starts to fall apart.
Chris: Is this Jamie's house party again?
The flowers
Jen: are dead in the vase.
Well, potentially.
I don't, I don't know.
Chris: I want to went to the… I want to get an invite to the next one.
Jen: But that's, that's like chronic stress, and your body's
stuck in that emergency mode with no time to actually repair itself.
Jamie: And you're telling me that's what does the damage?
Not the scramble, but the scramble that never ends.
Mm. Anyone can run a five-minute panic.
Nobody's built to run it for a long time.
Chris: Yeah, and that's it in one line.
So in short bursts, this saves you, but if you run permanently, the same
chemistry that helped you starts wearing the body down system by system.
Jen: And the heart shows it the most clearly.
So chronic stress is now, uh, treated as an independent risk factor for
cardiovascular disease, and it's ranked alongside high blood pressure,
high cholesterol, and smoking.
I think that's fascinating.
Wow.
Jamie: Hang on.
So you're putting long-term stress into the same bracket as smoking?
Jen: Yeah.
And- The effect on the body
… Chris: I know.
And it, I mean, it sounds dramatic, but there is actually method
to the madness, isn't there?
So, um, adrenaline and cortisol keep your heart rate and your blood pressure
up, but over time, that damages blood vessels and builds plaque in the arteries.
And in fact, there was, um, there was a 2023 study that found that depression and
anxiety, which sit right next to chronic stress, they raised the risk of a major
heart event by about 35% and brought the warning signs forward by about six months
Jen: It's huge.
And people with the highest cumulative stress scores, they showed roughly a
22% higher risk of that arterial plaque and a 20% higher risk of cardiovascular
disease independent of the usual suspects.
Jamie: So although stress doesn't hand you a heart attack on
the spot, it quietly moves the whole- Yeah … timeline forward.
Chris: Yeah.
Absolutely.
And that's the shift that matters.
So if you've already, if you already know you've got kinda hearth- heart
risk factors, it's a reason to have a kind of sensible conversation with your
GP, but it's not a reason to panic.
Jamie: Yeah.
So be wary of it if you're in the high risk category, but carry on calmly.
Chris: Absolutely right.
Yeah.
And, um, in terms of the immune system, so the immune system's
response to stress can be useful, but it can also be counterintuitive,
and it depends on the timeframe.
So in the short term, as we mentioned earlier, a burst of stress actually
sharpens your defenses and your body braces for a possible injury.
Jamie: So the five-minute stress version is the immune
system rolling up its sleeves.
Mm-hmm.
Jen: For a few minutes, yes.
But run it for months and it flips.
So sustained cortisol, that suppresses parts of your immune response, so it
slows your T-cells, and there's ev- even evidence it blunts how well vaccines work.
Mm.
Jamie: That's the cruel timing everyone knows.
You're never ill during a busy stretch, and then as, as soon as the holidays
come along, you get ill the first day.
Jen: Oh, that's happened to me so many times.
Chris: I know.
Everyone.
It's like it knows, isn't it?
Jen: I know.
Chris: Yeah.
And it's a genuinely common pattern, isn't it?
And the timing fits because, um, there's reasonable evidence that this low-grade
inflammation feeds into some autoimmune conditions too, so things like, uh, lupus
or rheumatoid, rheumatoid arthritis.
Though, it's worth saying that this is an association researchers are still focusing
on, so there's not full-on conclusions yet, just to put the caveat out there.
Jen: Yeah.
And that caution matters because the honest version is more
useful than the scary one.
The better established story is the brain, the hippocampus, which is central to
your memory and learning, is especially sensitive to a long soak in cortisol,
and it can actually shrink a little, which makes your memory, it can make
your memory and focus feel foggier.
Mm. Which is never a good thing when you're trying to live day to day.
Jamie: So the walking into a room and forgotting, forgetting why you went there
thing is, uh, is not you being hopeless.
It's just chemistry.
Chris: Largely, yes.
And, uh, naming it that way is actually kinder, I guess, a
bit more generous and accurate.
Um, and th- there's even work or research that's shown that our brain's cell, um,
telomeres, which are the protective caps that are on the end of our DNA, were
about twice as long in healthy people as in people with major depression.
So chronic stress does actually seem to age people faster.
Jen: And the simplest effect of it all is the muscles.
So under stress, your muscles brace like almost like a flinch and, you
know, they're meant to let go once it passes, but stay braced for weeks
and you get those, like, tension headaches, your tight neck, your
aching lower back, and you probably don't think of stress as the cause.
Jamie: Tight neck I can confirm, and the gut's on the same list.
That off-your-food feeling when you're feeling stressed.
Chris: Absolutely.
It's de- it's definitely on the same list.
Mm. So digestion actually is one of the first jobs that the body
drops in order to kind of deal with a, an immediate emergency,
um, when it's being stressed out.
So when you are stressed, that's why you often get this kind of knotted
or queasy feeling in the tummy.
Jen: Oh, that's such a horrible feeling, isn't it?
Mm. I get that sometimes.
But it, these effects, they don't hit everyone the same.
So there was a Mental Health UK burnout report found 9 in 10 people had felt high
or extreme stress in the past year, and the 18 to 34s are the, are carrying most
of it, and a lot of those stresses were tied to work, money, and working hours.
Chris: It makes sense, doesn't it?
'Cause, you know, the 18 to 34, you know, the age group we're all in-
Jen: Yeah, yeah, yeah … of course, yeah.
Chris: Yeah.
That's often the stage of life that we've got the kinda least control, um, over
your time, but the most uncertainty ahead.
So the same pressure lands harder when you're rushing around or, you know,
you can't see the wood for the trees.
Jen: Yeah, yeah.
Jamie: And can we kill the unhelpful myth while we're at it,
it's all in your head, just relax?
As if you could think your blood pressure back down by deciding to.
Jen: Can you imagine if you could do that?
Chris: Yeah.
The power
Jen: Yeah, I agree.
You know, but thoughts are real.
We have to acknowledge that.
And then, but so is everything downstream of them, so like the
raised heart rate, the cortisol, the suppressed immune response.
None of it's imaginary, and so telling someone it's all in their head, which
I'm sure happens a lot, it's both unkind and it's frankly wrong, isn't it?
Chris: Yeah, absolutely right.
And of course, it, it cuts both ways, doesn't it?
Because, because the response is physical, the things that calm it when it comes
to stress are often physical too.
So you don't have to somehow win an argument with your own brain to make
a difference, and in fact, you might get a few funny looks if you're trying
to argue with yourself in public.
Let's be honest.
Jamie: Right.
The bit I've been waiting for, what actually moves the needle, and
what's just a nice-sounding noise?
Chris: So by a distance, the strongest evidence is for
movement, probably unsurprisingly.
Mm. So research consistently shows that physical activity reliably lowers
cortisol and improves sleep, and this has been reported in multiple studies.
Um, importantly though, it's the dose is far gentler than most people realize.
So you're only talking about 20 minutes or so of something moderate.
So most days, if you do s- some kind of moderate exercise, even
brisk walking, that makes a colossal difference to managing stress.
Jen: Which I love this because as a runner, I'll take any excuse, um, to
get outdoors and to move your body.
But the real headline is consistency beats intensity, doesn't it?
So a steady walk you keep up does far more than that occasional heroic session
that you dread and abandon- Yeah … and then you're sore for days afterwards.
Jamie: Yes, and without sounding like a motivational quote, the best exercise
is one that you will actually do.
Jen: Yeah, absolutely.
Chris: You always sound like a motivational quote.
Uh, but you're absolutely right.
And, um, then we've got the kind of in the, in-the-moment
option, I suppose we'll call it.
Which, uh, so the fastest tool to kind of de-stress is to work on your breathing.
So we should all do this together.
So a double inhale through the nose, then a long, slow exhale through the
mouth, and in this kind of exercise, it's the out breath that, which is
the active part because it's gently putting the brakes on your heart rate.
And so just like the movement approach, it's something really straightforward
to do that makes a big difference.
Jen: Yeah.
Jamie: But a word of warning with the breathing technique,
do it discreet, discreetly.
A big dramatic sigh in a meeting might reflect badly on the last
person's comment who just spoke.
Jen: Yeah.
Chris: That's true.
It takes me back to the yawning episode we did.
I, I couldn't stop yawning- … all the way through that, uh, episode.
Yeah.
Jen: You know, and that office sigh is a loaded gesture, but it, it
works maybe without the theater.
Um, but the slower tools are, are strong too.
So there's good evidence that an eight-week mindfulness course around
10 to 20 minutes a day actually lowers cortisol, um, and gives the
brain a bit of a nudge as well.
Chris: Yeah, definitely.
And, um, there was one trial that found that kind of course held up about as well
as a common anxiety medication, actually.
Uh, but I need to put my Captain Sensible hat on again, as always.
Always.
Uh, that please don't take that comment as a recommendation to
swap your medication for an app.
Jen: Yeah,
Chris: definitely.
So if you're taking medication and thinking about changing direction,
always speak to your doctor.
Jen: Yeah.
Jamie: Sensible.
Easy to run too far with a headline like that.
Jen: Yeah, definitely.
Chris: Uh, yeah.
I've always got to put the disclaimers in, you know-
Jen: Yeah,
Chris: um- … just, just in case
… Jen: we love a, a Captain Sensible
Chris: air.
Yeah.
I know.
I have to fight for the Captain Sensible fit.
In fact, where's Matt?
Uh, Matt will sometimes try to take it off me.
Oh, so two more points that have solid backing here.
So the first is sleep and stress feed each other, which is no surprise.
Mm. So we know that poor sleep, oh, sorry, poor stress makes you, you more
reactive, and stress wrecks your sleep.
So working on your sleep has a huge impact on stress, but indeed,
working on stress has a huge impact on sleep Um, the other is simply
actually being around other people.
Yeah.
So regular social contact measurably steadies the stress chemistry.
Jen: That's interesting.
Jamie: So a walk with a friend is basically a double dose, movement
and socializing at the same time.
Chris: Absolutely.
Jen: Yeah.
It ticks several boxes at once.
Um, and diet is another one people think about.
So just to be straight, the evidence with diet impacting stress, it's much thinner.
Um, there is early work that omega-3 fatty acids might blunt the body's
blood pressure response to stress a little, but it is emerging, it's not
proven, and I wouldn't oversell it.
Jamie: And I'm the last person who should oversell it, given that I
co-own a company that sells omega-3.
Our omega-3 is a good product.
It's not a stress cure, and I'd rather tell you that plainly
rather than dressing it up.
Jen: Yeah.
Chris: I think we've got to kind of flash a product in
front of the screen, you know.
Yeah.
We're not trying to sell it, you know, or make any claims.
Um, I'm gonna put my last Captain Sensible hat on again- Yeah … if you don't mind.
Um, if stress is genuinely affecting your health, your sleep, your mood,
et cetera, that's a conversation with a doctor, not a podcast.
So the support out there is strong when it comes to stress, and using it is smart.
It's not a failure.
No.
It's really important to
Jen: point that
Jamie: out.
Mm. So why does stress make us feel ill?
Jen: Because the body has a fast, powerful emergenc- emergency response that it's
super for, like, a short scramble.
It raises your heart rate, floods you with energy, and switches
off everything non-essential.
The harm isn't in switching it on.
It's n- in never switching it off.
So the heart, the immune system, brain, the gut, they all spend months
running in a state that was actually only ever meant to last minutes.
Jamie: So the goal was never a stress-free life.
That doesn't actually exist anyway.
Mm. It's actually making sure the guests at my dinner
party- … actually leave eventually.
Hobs back down, washing up done, the kitchen back to itself, um,
before the next lot turn up.
Chris: And that's the key point.
Maybe not the dinner party, but the key point is you're not broken for feeling it.
Jen: Yeah.
Chris: You just need the off switch to work as well as the on switch
does when it comes to stress.
Jen: Yeah, definitely.
So that is it for this week.
Make sure you hit that subscribe button.
We're unpacking the science behind everyday questions each week.
Tell us in the comments what you'd like us to explore next.
Thanks for geeking out with us, but for now, that's it from me.
Jamie: That's it from me.
Chris: And that's it from me.
Jen: Bye for now