ZOE Science & Nutrition - The daily step count that cuts inflammation in half | Prof. Janet Lord

Episode Date: June 19, 2025

What if the fatigue, stiffness, and brain fog we blame on aging are actually symptoms of something we can change? In this episode, immune aging expert Professor Janet Lord unpacks “inflammaging” - a slow, chronic form of inflammation that quietly builds in the body as we get older. It’s now believed to drive many of the diseases we associate with aging, from dementia to heart disease. Janet reveals how this invisible inflammation takes hold, how it silently damages the brain, gut, and immune system - and what science says we can do to fight back. Her research has shown that even in your 70s, it's not too late to reverse immune aging. One small change tomorrow could make a measurable difference. Professor Janet Lord is a world leading expert in the biology of aging. She’s published over 200 scientific papers and advised UK health policy. Her groundbreaking work shows how daily habits - especially movement - can reshape the immune system and slow the effects of time. If you want to stay stronger, sharper, and healthier for longer, this conversation could change the way you think about aging. 🥑 Make smarter food choices. Become a member at zoe.com - 10% off with code PODCAST 🌱 Try our new plant based wholefood supplement - Daily 30+ Follow ZOE on Instagram. Timecodes: 00:00 What is inflammaging? 02:23 The biggest misconception about inflammaging 03:20 Inflammation can grumble away for decades 04:01 What cytokines in your blood really mean 05:00 Why inflammation is helpful — until it isn’t 06:19 A small rise in inflammation can last for decades 07:45 Inflammation acts like immune system hormones 08:50 Why more immune activity isn't always better 10:00 Did modern life create chronic inflammation? 12:00 Why flu is deadly for older people 13:15 Inflammation breaks down muscle and bone 15:15 Why fat tissue is fueling your immune system 16:51 Why body fat isn’t just a passive energy store 18:10 How inflammation helps cause dementia and heart disease 20:50 In your 40s? You might already be aging faster 22:03 Why menopause triggers a rise in inflammation 24:40 The gut bacteria that leak into your blood 27:15 Your muscles produce anti-inflammatory signals 28:55 Sitting too long cancels out your workout 30:44 Why walking stairs beats living in a bungalow 33:35 Janet’s one-day-a-week fast for 30+ years 34:55 10,000 steps = no inflammation? 35:57 Overweight people see the biggest benefit from exercise 📚Books by our ZOE Scientists The Food For Life Cookbook Every Body Should Know This by Dr Federica Amati Food For Life by Prof. Tim SpectorFree resources from ZOE Live Healthier: Top 10 Tips From ZOE Science & Nutrition Gut Guide - For a Healthier Microbiome in Weeks  Have feedback or a topic you'd like us to cover? Let us know here. Episode transcripts are available here.

Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health. Wrinkles, grey hairs, sore knees – these are visible signs of ageing. But deep inside, something else is quietly changing. And it starts many years earlier. Inflammation. A low, constant burn in your immune system. It can cause your muscles to decay, your arteries to fur up and your body to age prematurely. Scientists now believe that this silent inflammation is behind many long-term diseases, from dementia to heart disease. But unlike aging, inflammation aging isn't inevitable.

In today's episode, we explore the surprising daily habits that could keep your immune system younger for longer. We're joined by Professor Janet Lord, Director of the Institute of Inflammation and Aging at the University of Birmingham. Janet is a world leader in immune aging research, and her work uncovers how lifestyle can rewire the way we age. By the end of today's episode, you'll

know how to spot the hidden signs of inflammation and how to fight back. to spot the hidden signs of inflammation and how to fight back. Janet, thank you so much for coming in to speak with us today. My pleasure. So we always start the show with a rapid fire Q&A with questions from our listeners.

And we have some very strict rules. You can only say yes or no, or if you have to give us a sentence. I'll try my best. Can inflammation speed up your rate of ageing? Yes. Can inflammation increase your risk of dementia? Yes.

Can chronic inflammation weaken your immune system? Yes. Does everyone experience ageing due to inflammation in the same way? Yes. Does everyone experience aging due to inflammation in the same way? Yes. Are there lifestyle changes that can improve my immune system even later in life? Yes. That's a lot of yeses. Final question, you get a whole sentence for this.

What's the biggest misconception when it comes to inflammation. That people assume it's purely down to problems, defects in your immune system and that's not correct. You know when I was a kid growing up, I thought about aging as being mainly the things you see on the outside. So like wrinkles and grey hair, but also sort of moving more slowly and just not being capable of sort of the things that you were capable of when you're younger. And I definitely thought this was inevitable. It was just like something that happens in the same way as a child, you know, you get taller every year. And I'm going to share the good news for our listeners, which is I know that you've done a lot of research about a daily practice that can help to fight this inflammation, maybe even reverse it. But before we get onto that, inflammation, what is that? Basically, it's an increase in inflammation

in the body as you get older, so with age. So it's the two things combined. And most people would think that inflammation, if they've heard of it, they assume it's something that happens when they cut their hand or if they've got a chronic disease like rheumatoid arthritis, oh I've got inflammation. But with aging it's broader than that so it's a low level, sort of grumbling level of inflammation that goes on for years. So if I measure inflammation in your blood it's not like

that level that you would see in an infection or if you've got a chronic inflammatory disease like rheumatoid arthritis or inflammatory bowel disease. It's much lower than that, but you've got it for years and years grumbling away there. And that affects how I age? It does indeed. We didn't know for many years really what caused aging but now we're really beginning to understand the processes in the body that drive aging that cause us to become more prone to diseases like dementia, like

cardiovascular disease, like even cancer and it turns out that inflammation is one of those key processes. So inflammation is one of those key processes. So inflammation is one of these words that I feel we hear a lot, but I'm probably not the only person who still struggles really to understand what's going on. And I was just thinking about what you just described to me, because I managed to smash up my finger yesterday one way or another, and it's really sore this morning. In my mind, that somehow my finger is inflamed.

Is that correct? That's correct. No, that's correct. What's going on there and how is that the same or different from this like low long level inflammation? Exactly. So like everything else in the body, inflammation isn't always bad. It's there for a reason. We've evolved to have inflammation and so its primary focus is to repair damage in the body. So if you cut yourself you have inflammation and it stimulates repair processes. Its other key function is in

combating infections. So inflammation really stimulates your immune system, directs it in the correct way. So is your infection a bacteria or is it a virus? And depending on which it is, the immune system will then be educated to behave in a particular way. And inflammation is important to that. But that's all acute inflammation. It's rapid it goes away when the problem is resolved so when your cut has healed itself when the infection has been cleared it subsides. This inflammation is there at a very low level and it's there for years and years

so for example if you get an infection the level of inflammation would perhaps increase a thousand fold in your blood and in the organs in the body. But this inflammation is actually just two to three fold higher than when you compare, say, a young person and an old person. So it's low level, but it is there for decades. And Janet, when you say it's inflammation is in my blood or in my body, what does this mean, this thing that you're describing? Yes. So when we measure inflammation, if say we take a blood sample, what we're actually measuring is proteins in the body

that are stimulating either tissue repair or helping your immune system. So they're proteins, their correct name is cytokines and we can measure them in blood very easily. You can actually also measure them in saliva. So there are common ones. There's one called CRP, which is often measured if you go to the doctors and they take a blood sample. It's a common one that's measured. Other ones are called interleukins. So they're proteins in the blood and in the rest of the body.

It's a bit like, you know, the ambulance control centre that is sending the doctors and the ambulance to this place and organise everything and say something's going wrong here. Exactly, exactly. So it has phases. So when you have an inflammation in response to say an infection or tissue damage, you get that first signal out and that's where CRP comes in and then it then educate or instructs other cells in the body primarily the immune system to make other cytokines and they then go on and immediate if it's tissue repair or if it's an infection then they direct

the processes so you're quite right it's really it's a signal it's a communication system in the body a bit like hormone, I often say they're immune hormones. So that sounds great to have all of these like little doctors rushing around in my blood fixing things. So why isn't having that like twice as high all the time better for me? It sounds like we always say there's, you know, there's not enough doctors, there's not enough beds. That sounds like, well, it's twice as high, isn't that like twice as good?

Right, no, no, it certainly isn't. So if you don't turn that inflammation off, then unfortunately it can be damaging. So for example, too much inflammation will actually suppress your immune system and make you less able to fight the infection. And some of your viewers may remember during the pandemic that they may have heard about cytokine storms with the people with COVID-19 who were not doing very well and that's exactly what was happening there. The cytokines were too high and so they're then causing damage in the body so they can damage the blood vessel walls but they can also suppress and damage the immune system. It's too much of a good thing as

it were. You've got to have that goldilocks spot, just the right amount of inflammation to stimulate the tissue repair or educate the immune system and then you need to turn it off. So what happens a lot as you get older, you're not as good at turning off the inflammation. So for example, in COVID-19, one of the problems for older adults was they would respond to the infection with the virus, but then they were not very good at turning it off. Then their inflammation persisted and then damaged their lungs and damaged other systems in the body. I think you're saying that like inflammation is natural and healthy and you need it when you cut yourself or you got an infection. But the sort of the byproduct of that inflammation

is actually damaging to my body over time. So it's important that I like I get it turned off. Exactly right. If it's left on. Yeah. Then timing is crucial. So timing and the amount of inflammation is absolutely crucial. Like I said, it's that gold elok spot. You have to get it just right. Now I know your sort of subject to study now for many decades has been this inflammation. Is that something that has always been with human beings or is this just a product of modern life? That's a really good question. I guess the answer is we don't truly know but we do know that some aspects of modern life will promote more inflammation. that some aspects of modern life will promote more inflammation. So for example, when we were hunter-gatherers, we were very physically active.

If we didn't catch a saber-toothed tiger that day, we would go hungry. So we had periods of starvation. So we didn't eat three meals a day. So we were physically active, we didn't eat three meals a day. Now with our modern lifestyles, food is readily available, we're more sedentary as a population, and we know both of those things will increase inflammation. So I would guess that yes, it's a more recent thing and that, you know, it's something with our modern lifestyle that is really driving this inflammation.

And as I'm listening to this, I think I'm getting a better picture of sort of the inflammation. What are the signs of ageing that can be affected by this inflammation and the way the immune system is not working as well? So I'm going to give you two examples. So one thing, as I've said, the inflammation can actually suppress your immune systems, so you're more susceptible to infections. And when you actually get an infection, it takes you longer to clear it. So again, most of your viewers will know if you're a 20 or 30 year old and you get flu,

you have a week or two in bed, you have a few duvet days, but then you're fine. But if you're 70, 80 years old and you get the flu, there's a good chance you could end up in hospital and even die as a result because you get secondary infections like pneumonia as well. So that's one thing, that's one very visible thing that most of your viewers will know that the older you are, you're in a high risk category. Coming back to my thinking, isn't that just what it means to be older? You're looking at me like, no, definitely not, Jonathan. It is a marker of aging, so it's something we recognise, but it's not inevitable. And so you're saying that this is because the immune system has declined.

Yes, it's compromised. Because of this ongoing level of inflammation. Yes, it's certainly one of the key drivers, we think. Other things happen as well that can affect your immune system, but inflammation is looking like a major driver. Another aspect that, again, your viewers will recognise and think about as an old person is walking more slowly, perhaps less struggling to get out of a chair,

groaning every time you get out of the chair. And that is because with age our muscles, we have less muscle and it's less good quality muscles. It's called sarcopenia. So you lose muscle strength and we know that inflammation is one of the drivers there. So this inflammation actually does lots of things to muscle. It slows down the production of molecules that you need to grow the muscle. They're called growth factors. So it suppresses that. It also causes the production in the muscle

of hormones, stress hormones. And again, some of your viewers may have heard of one called cortisol. And cortisol breaks muscle down so it's suppressing the growth of new muscle and it's accelerating the breakdown of existing muscle. So again, inflammation we know drives this cortisol production and suppresses these growth factors.

It's one of the factors that's causing this frailty. Janet, that's amazing. I've never heard that before. So you're saying that if my inflammation is higher, it's actually basically like reducing my muscles and like breaking them down and making it hard to build them. Exactly. So it's one of the things that's going to increase the risk of an older adult becoming physically frail. And I'm also thinking just about how we live in this life now that we know it's somehow less healthy

and there's more inflammation and I never heard that that could actually affect my muscles. It's not just about something... Muscles and bones, same issue with bone. It can be one of the drivers of loss of bone as well. So all around musculoskeletal frailty, inflammation is a real issue there. Inflammation is a real issue there. So what is triggering long-term low-level inflammation? Why is it that the body isn't just turning it off if it's a bad thing? Right, okay. So as I said at the start, it's actually multifactorial.

There's no one thing. From the immune system side of things, as you get older, your immune system is just less good at turning off. So you have immune cells, some of them are pro-inflammatory, they cause inflammation so they produce these cytokines. And then you have other aspects of your immune system that suppress the cytokines, they're anti-inflammatory. And as you get older, the anti-inflammatories, there's less of them around. So you're less good at turning it off. So Janet, again, because I'm learning so much, my inflammation doesn't just stop.

Actually, my immune system has to switch it off. If it doesn't switch it off, it just keeps going. And as you get older, you've got less of the immune cells that turn off the inflammation. So it tends to grumble along so that's one thing. Another factor is adiposity so fat tissue in the body. A lot of your viewers may think well it's just there and it stops me doing my genes up very easily but actually fat tissue is pro-inflammatory it produces these cytokines and as you get older the fat tissue produces more of these cytokines. And as you get older, the fat tissue produces more of these cytokines. So you have more of this fat tissue as you tend to get older,

if you're not keeping physically active, etc. So that's one of the factors, the more fat tissue you have, particularly around the abdomen, around your tummy, that really produces inflammation. And Janet, I feel that we've always been taught that your fat is sort of inert. It's just like it's a store of energy and we all know that we don't want to have it.

And I think we increasingly know that it's bad for our health because if it ends up in our arteries or something that's bad. But what you're describing is actually creating signals that are turning on my immune system. Exactly, yeah. And the fat tissue itself, the cells in there, they make these cytokines, but they also attract in immune cells.

So your fat tissue also has immune cells inside of it producing cytokines as well. So it's really all around bad news basically. And have we always known that? We've known this really probably for about the last 20 years I think so it's pretty recent really and you know they produce also unique cytokines called adipokines. So they're just made by fat tissue but as I said they also recruit in immune cells. And is this why living with obesity is so bad for your health? Yes, it's a big factor.

I mean, there's the physical strain on your heart, etc. But yes, that amount of fat tissue you have, you've got much more inflammation. So yes, it's one of the big downsides of having too much adipose tissue. And we know, I think everybody knows that we're living with this sort of crisis growth in obesity. So has that meant that there's also been a really big growth in this long-term inflammation that you're talking about? Yes, certainly.

When you look at, you compare somebody with a healthy BMI and then somebody overweight and obese, you know, there's just a rank increase there in the inflammation. And, you know, the higher it goes, that then increases your risk of heart disease, dementia, etc. And also frailty, as I've mentioned. Can you help me to understand the second half of this? So, my inflammation has been up for a long time. You've mentioned that my immune system is a bit worse. So I understand that I'm now at more risk from flu. But how does that link to all the things that we worry about as we age, you know, dementia and heart disease? Are they separate? And this is really just about a risk of infection?

No, no, no, they're completely linked. So that inflammation is one of the drivers for your cardiovascular disease, your heart disease. We don't fully understand why, but we know, for example, some of your viewers may have heard of atherosclerosis, so this sort of thickening of your arteries, and in that thickening there is fat tissue in there, but again, also immune cells are in there producing these cytokines actually in your blood vessels. This is narrowing them, meaning that the blood is having to go through tighter, raising your blood pressure etc. And so damaging your blood vessels and your heart. Dementia, again, we don't fully understand what the problem there is.

It could be that in the brain itself that you get damage build-up and your viewers may have heard of things like plaques and because your immune system doesn't function as well, it's not getting rid of those plaques, it's not clearing them and so they're causing inflammation and then damaging your actual brain cells. So it's really all, no matter the inflammation when it's at that raised level for many years, it's just like I say nibbling away and damaging different parts of the body. You know, we've mentioned the muscle as well. It's just everywhere. And it may be in different individuals that they're more prone to the heart disease or more prone to the dementia, but it's there pretty well. If you think about it, it's in every part of your body.

Is this something that only starts when you're already getting quite old? Yeah, so that's a really good question. So at the moment we're still in the stage where we don't know if the inflammation comes first and then the disease or whether some of that inflammation is caused by the early stages of the disease. So for example, you know, the heart disease, is that then raising the inflammation? And it's probably a bit of both. So there are lots of studies that look at what you'd call really healthy older adults, they've got no obvious chronic disease and you often struggle to find the inflammation in those people. But the ones that have say got their first-age related disease or a highly sedentary or overweight, then you'll find

it. So it's probably a little bit of both. I think that if you put on that extra weight, if you become very sedentary and not physically active, then you're going to raise that inflammation and then that's going to drive your risk of disease. And then once you get that first disease, that will have inflammation with it as part of the disease process.

So it's a vicious circle. And can you be living with raised inflammation already if you're in your, I don't know, 40s for example, for a long time before you start to see any of these impacts? Yes, you certainly can. So if you, you know, look at say somebody in their 40s who is again sedentary, overweight, they'll have that inflammation. So they're aging rapidly, more rapidly if you think of it that way.

And so you can have three people in a room and they might all look fine but they might in fact be aging at very different rates because they've got this inflammation level? Exactly, yes. We do know that people do age at different rates and that's why, again, some of your viewers will know a 70-year- old who's out running marathons and another one who's, you know, sat by the fire with their slippers on, you know, watching daytime TV and feeling very old. And you're sort of saying you can maybe look back 30 years before into their bloods

and you would probably already be seeing these different levels of inflammation. Yes, yes, and for women, you know, one of the tipping points can be the menopause as well because we know that female sex hormones are anti-inflammatory. So women are often doing absolutely fine till they hit the menopause and then they lose their oestrogens or they're much lower. And so they've lost one of their protections against inflammation. And so they need to be really thinking about doing things to try to improve their anti-inflammation and keep that inflammation down.

Because there's a really big shift suddenly to how their body is working. Totally, totally. Are some people more vulnerable to inflammation than others? So you've mentioned menopause as a point in life for all women, but are there any other things that mean

that you might be more at risk of this than someone else? Again, the evidence there is not massively strong, but we do know that people have certain versions of genes that will predispose them to have more inflammation or to not be able to turn that inflammation off. So that is there. There are some very large studies that have looked at different genes that regulate the amount of these cytokines that you have and they can vary from person to person. So there is, yes, a genetic predisposition, but a lot of it is lifestyle.

I know we're going to start to talk in a minute about all the things that you can do, but one thing we haven't talked about at all is the gut microbiome and that comes up a lot on this show and I'm curious about whether that plays any role in this inflammation you're talking about. I think we're really realizing that it does now, we're becoming really aware of the key role that the gut microbiome and the oral microbiome play in inflammation. So your microbiome in your early development helps to educate your immune system because you have a lot of immune cells actually in your intestinal

tract and so they're in contact with the bacteria and the bacteria you know the good the helpful bacteria they really help in a lot of ways so they help in generating the lining the mucus in the gut, so that your guts, we say it's impermeable, so the contents of your gut don't leak out into your blood system. They produce products that again make your immune system less inflammatory. As you get older, what we know happens is there's a tendency for your microbiome to be less diverse and to have less of what we would call the helpful bacteria and more of a bacteria called a pathobiont which is unhelpful. And these pathobionts,

what they can do is increase the chance that your gut becomes leaky and so some of these bacteria can get into your bloodstream and of course your immune system then sees them as a threat. They're bacteria from your gut that you've had all of your life. But actually once they're in your blood system, your immune system thinks, well, that's a bacteria. So it responds and there's inflammation. So yeah, so keeping that microbiome in a healthy state

we now know is very important. And so if I understood rightly from what you're describing before, like one of the biggest things with inflammation is having to switch it off. We live our modern life, I'm going to get a virus or I'm going to cut myself, but switching off is important. And so I think you were saying that one of the things that my microbiome might be doing if it's healthy is supporting the switching off.

Well, mainly in the gut itself, a healthy microbiota is what it's actually reducing, is the signal for inflammation, so the on signal. So if these bacteria get out of your gut and into the immune system, that's an on signal, that's a threat. So it's more that they're reducing the on signal. Not triggering it in the first place for an unnecessary reason. So I'd love to talk a bit about what we can do, because I think you're now painting this picture that inflammation is playing a really big role, I think, in how many healthy years

we're having to enjoy. But there's one intervention that I know that you've studied really extensively, and I understand that's exercise. I think lots of people listening is like, well, you know, I know that exercise is good for me, but what's that got to do with my immune system and inflammation? Can you help us to understand, Janet? I can, again, lots of ways. And as you said, we've known for a long time

that the more physically active you are, you reduce your risk of a whole range of diseases, you're likely to be longer lived and have a longer healthy lifespan. And it's now becoming clear that this might be because exercise reduces inflammation. And it does it in lots of ways. So if you're being very physically active,

you're less likely to have too much adipose tissue, just too much fat. So you've reduced one of those sources of that inflammation. By doing that, you've reduced the risk of your vessels being damaged. I told you earlier about inflammation reduces your muscle mass and strength so you've reduced one of the causes of you feeling more frail and less able to function physically. The other thing that your viewers may not be aware of is that muscle itself actually can be anti-inflammatory. I didn't touch

on that earlier but moving muscle produces cytokines that dampen the inflammation down particularly they educate immune cells to be anti-inflammatory and so the more your muscle is moving the more it's producing helpful cytokines to dampen the inflammation and the more sit, the less of those are being produced. So that's why we know that sedentary time is also important. So your viewers might struggle with this one. So they're two different factors. So the time you spent doing exercise is great. It's going to give you all of these benefits, reduce the inflammation, help you to be more anti-inflammatory. But if you then, say you do your 45 minutes of exercise in the morning, you go and walk

the dog or you do a little jog, whatever you do for your exercise, and then you sit then for eight or 10 hours watching daytime television or you're at work and you're at your desk, you can undo a lot of that because the muscle will then not produce that dampening cytokine for that long period of time. So now we know that yes, you need to be physically active, but also don't be too sedentary. If you're sitting, you've got a desk job or you're at home, you're retired now, perhaps every hour get up and move around, even if it's just for 10 minutes. I think I'd understood why that might be good for my heart or something, all these things like, you know, just having the muscles is good, but here you're describing

the way that it's directly sort of almost orchestrating my immune system. Is that? Totally, totally. It turns out that your muscle is a major regulator of your immune system. It can make it less inflammatory basically and so if you're not moving then say you get an infection you're much more likely to have this overshoot with your inflammation. As long as you break that sitting time up and then this pro-inflammatory system can't really get established so you get up you know after an hour move around and then this pro-inflammatory system can't really get established. So you get up, you know, after an hour, move around and then, yeah. Because sometimes, you know, you may not be able to, you know, stand up all day. I had a standing desk at work and so I did stand all day.

So think about that one. That's another good one to think about. So one thing you're saying is, don't sit for a long time, I need to walk around because then I'm getting all of these benefits from my muscles that are sort of dampening my inflammation. What about the exercise itself? I guess how important is that 45 minutes of something more intense and what do you need to be doing to get the benefit to fight this inflammation? Yeah so we sort of class exercise it in two broad areas as aerobics so that's basically anything

that raises your heart rate, gets you a little bit out of breath. And that is very good for reducing the inflammation, for helping your heart, helping your lungs, as well as your muscle function itself. And the other type of exercise is what we call resistance exercise. So that's strengthening, this might be band work,

or if you go to a gym, lifting weights, or I I always say to people you don't even need to go to gym just go up and down stairs and then you know that's a really good exercise. It's aerobic and it's resistance but the resistance is more important for the building of strength of your muscle and the muscle mass. So ideally you need to do both. The aerobic to bring the inflammation down, the evidence is stronger there for aerobic bringing inflammation down, and the resistance to keep your muscles themselves a good size and good function. I always say, you know, worst thing you can do is an older adult is to go and get a bungalow or live in an apartment with no steps and you'll end up with bungalow legs, so legs with less muscle and less strength. That's really interesting I

heard this on speaking to another scientist a little while ago thinking about you know what you should do with your parents and I definitely was brought up with this idea that you know as your parents get older or anyone gets older like they should take it easy they shouldn't have to carry their own bags and he was saying oh no you should shouldn't make your parents carry the shopping upstairs if you really love them. Is that really true? Yeah, absolutely true.

Yes, my mother, when we were looking for a home for her to move into when she was downsizing, she wanted a ground level apartment. We said, no, mom, you're getting one with stairs. You're on the first floor or the second floor. She wasn't pleased about it, but I think she enjoyed it eventually. And you feel that basically you were giving her more years of healthy life.

Absolutely. You're a ground floor, you're not using those stairs. You're not getting that exercise for your muscles. And it's such a simple thing to do. I always say to people for no other reason, every day, just going up, down your stairs 10 times, just for no reason, just go and do it as your exercise. And Janet, you're a scientist, so you like to talk about all the data and not about yourself,

but I feel that I have to ask this question as you said, are you one of the world's experts on inflammation? What do you therefore do for yourself as you think about exercise? Right, so I do a few things, so I exercise every day, so I'm a keen runner, I don't run every day now because I've now got a knee that's not in great shape. But I go to the gym, I swim. I do that four days a week. If I'm not doing that, then I will go out and do a brisk walk for about 30 minutes. But I always say to people, just do more than you're doing now. Don't get too worried about, oh, I've got to go and do 20,000 steps or whatever.

Just do more than you're doing now. So we did a study, this 10,000 steps a day, I don't know where did that come from, where's the evidence base for it? And there wasn't one, you know it was I think it was the Tokyo Olympics where it came into fashion. And so we looked at 200 older adults in Birmingham, we got them to wear a Fitbit and we looked at their steps and then we looked at how much inflammation they'd got. The ones that were doing 3,000 steps a day or less had really high inflammation. The ones that were doing 5,000 to 7,000 had dropped it by 50%.

By 50%? 50%. Only at 5,000 to 7,000 steps? Only at 5,000. And the ones that were doing 10,000, guess what? They had no inflammation. So it turns out the 10,000 did have something. But I always say to people, if you're just doing the five and seven, you're gonna have less inflammation

than somebody who's only doing 3,000 steps a day. Going from like 3,000 steps a day to five to 6,000, you're like half the inflammation. And you're saying that people at 10,000- They had no inflammation. Had no inflammation. So that's not a, you know, cause I think often we listen to this stuff on social media and people are doing three

hours in the gym, lifting their own body weight in both arms. Anyone who knows me knows that I can definitely not do any of these things. But you're actually saying just walking 10,000 steps a day is enough to switch this inflammation level down low enough. Yes. And will that work even if you're also, you know, quite heavily overweight, given what you were describing before

about the way that the weight was part of the problem? That's really interesting. So again, most of the studies where they've actually done an intervention, so they've got people to change their lifestyle, it does work best if you're overweight or obese. So those are the folks with that highest level of inflammation,

and they will tend to drop their inflammation. They'll have the biggest fall if they then do an exercise intervention. So it's true that basically it makes sense doesn't it? The more inflammation you've got the more chance there is that you'll make a drop when you increase your physical activity. If you haven't got much inflammation to start with then it's harder to get rid of it. You're doing more exercise than that 10,000 steps and that's because the benefits of exercise, I guess, it's not only for this inflammation, it's for other things as well. Yes, generally. So just feeling good about yourself. I think it helps with your mental health as well. So just all-around good and just feeling good. I'm a morning exercise.

I always exercise in the morning and I find it sets me up for the day. The other thing I do, which we haven't discussed so far, is that again a lot of your viewers will have heard about, is intermittent fasting. So I fast for one day a week, so I have my last meal on a Sunday evening and then I don't eat again until Tuesday morning. Oh wow, so you're not just talking about like reducing, not just reducing your time. I tried that, I didn't like that as much, this sort of six hours feed, but some people find they can't do the full... You have your last meal on Sunday evening and then you miss all of Monday. And then breakfast on Tuesday. So I find that incomprehensible since I know how grumpy I would already be by lunchtime. How does it make you feel? People say, well, don't you feel really tired? I say, no, it's the opposite. Actually, I feel wired.

You feel really alive. And that's because one of the things the fasting does is it stimulates cortisol in the body, which perks you up and it's the wakening hormone. So you feel alert. But we also know that whether you do the full fast like I do, or you do that six hours, that fasting period where you've got the 18 hours of fasting, it stimulates anti-aging

processes in the body, including dropping inflammation, but it also stimulates a process called autophagy, which in the body basically gets rid of all the debris and the damage in your body. And fasting does that. So we know roughly how fasting works now. It's like a little Hoover going around the body, hoovering everything up and getting rid of the rubbish. And how long have you been doing this for?

Been doing this since my 30s, so over 30 years now. And did that start coming out of your scientific research? No, to be honest, I had a lovely American antique called Aunt Maureen and she used to say it's for detoxing your body and so it was a big thing at the time and so I said okay I'll give it a try and then later when I began looking at aging and trying to find out how it worked then sure enough that's when I discovered actually what it really does is it does it is a detox because it gets rid of the rubbish in the body but it drops inflammation down and in turns on lots of anti-aging processes.

Is that a big part of what means you're continuing with this? Like it feels like you're doing this really healthy thing for yourself? Yeah, I think so. I even got my husband to do it now. It took me a long time to persuade him, but he's been doing it now for about seven years and we'd never go back to not having a fasting day. That's amazing. So what else can we do? Okay, so if you don't want to do the fasting or the intermittent fasting, just what you

eat as well can help. So we've mentioned microbiome already. So if you can get a nice diverse microbiome by lots of different fruit and vegetables in your diet, pulses as well, most of you will have heard of pre or probiotics as well. Try and have a really varied diet so that will help. The other thing is specific things in your diet, so things like unsaturated fatty acids, so vegetables oils and fish oils we know are anti-inflammatory, so they will bring the inflammation down.

So specific foods in your diet will help as well. And do we understand yet the exact microbes that we might be trying to support in our diet or is that like we hope one day we'll understand how that links through to the inflammation but we're not there yet? Yeah, I think we're getting nearer I think. We're getting nearer. So there's specific bacteria that seem to be really helpful and educate your immune system and keep the inflammation down. One of them are called the Fermicutes. So we are beginning to understand that and then the bad guys, the pathobionts, things like Staphylococcus

is in there. So we are beginning to understand, we're just trying to, I think the people working in that area are fine-tuning exactly which ones are doing which bit of the pro-health agenda really. So that's where the field is and particularly which foods might stimulate or allow them to grow in the gut. Do you know someone who's making an effort to stay fit and healthy? Share this episode with them. Janet's cutting-edge research could help them adjust their approach

and add more healthy years to their life. I'm sure they'll thank you. Now you've talked about fasting and you obviously go for something that's very impressive, but I think we know, you know, even from our own Zoe research, that it's, you know, it's very hard for most people to manage to fast and you're even more than 24 hours, but there's been a lot of interest in time restricted eating. So not not eating what the average American or British person does, which is probably for like 16 hours a day, but for a shorter time period. Is there any evidence about that having any effect on this inflammation? There is, yes. So that time restricted eating. so whether you do six hours of eating and 18 hours of not eating. Yeah, the evidence is there. A lot of it is still in the animal studies in mice and what have you.

So when they've put mice on this intermittent fasting, they live longer, they live healthier. But there have been studies in humans as well. A lot of them not for a long length of time, it might be three or six months. But in those studies, yes, they bring the inflammation down. And some of the other risk factors for say cardiovascular disease are down as well. So their lipids and their cholesterol change as well. So yes, it does seem that in humans, it's definitely going to help. What I'm understanding from you is so much of this is about somehow switching off the

inflammation. So why would not eating help switch my information down? Yeah, so some of it is like turning on this process of autophagy, so you're getting rid of damage in the body. And damage in the body is another thing that can cause the inflammation. It will stimulate your immune system. And what autophagy does is get rid of that damage.

It removes the damage in the body. So again, you've lost one of the on signals and of course if you're doing that intermittent fasting you will also drop the adipose tissue so again you're getting rid of another on signal and because you're reducing the inflammation remember I said the inflammation itself can bite back on the immune system and suppress it and cause it to be more inflammatory as well. So you're removing lots of on signals for inflammation with that intermittent fasting. That's

fascinating. Now, Krosz, we talked a lot about the things that we can add if you like to reduce this inflammation. I feel we haven't talked a lot about what is it in our environment that might be creating that long-term inflammation. I feel we haven't talked a lot about what is it in our environment that might be creating that long-term inflammation. And I know this is something my co-founder, Tim Spector, talks a lot about. And he tends to start with food, but I'd love to know from your research,

and I guess the research that you study, what's going on in our environment in 2025 that is leading you know, leading us to have higher levels of inflammation that then we're struggling to turn off? Well certainly, as you said, diet is in there, so we're eating, a lot of us are eating a diet that isn't promoting a good healthy microbiome, a nice diverse microbiome, but I think the other thing is, as I touched on earlier, sedentary time. We are really sedentary human beings now and we have not evolved to be sedentary. So most of the data now is showing that

when you actually accurately measure people's physical activity, that as we get older we're doing less and less physical activity. And if you look at 65 year olds, only 10% of men are being physically active enough. So following the chief medical officer's guidelines of 150 minutes of aerobic exercise a week and ladies it's even less, it's down below 5%. So Janet, only 5 to 10% of people who are 65 are actually following the general guidelines about how much activity. That's right. Yeah, so there are lots of research that's done by a questionnaire, so asking people

how physically active they are. And we're humans, we tend to overestimate a little bit. But in studies where they've actually got them to wear a Fitbit or some sort of thing that's measured how active they are, then the figures are much lower and in the over 65 year olds, they're in that five to 10%. This reminds me a lot of what I hear about food, where it's the same thing where you look at how much fiber, for example, people are eating in the US or the UK, it's at the same sort of level versus the guidelines.

So there's this huge mismatch. How much of this is like people just don't have enough willpower and how much of this is that we sort of built our lives in a way which is just at odds with how we're meant to live and therefore somehow if we could redesign our life a bit, a bit like you said with your mother and making sure that there are stairs to go up and down to a flat. How much of it is sort of somehow designing your life better to solve it? I think a lot of it is people, you know, that they've got very busy lives, you know, our lives now, you know, people often be commuting, perhaps a long time to work, or even if they're

working at home, you know, they're sitting at home, they're largely sedentary. And I think a lot of the time, people probably just not thinking about it. You know, I think once you speak to people and you explain, well, you know, why we age, why we lose muscle, why our immune system might not be working and some of the ways that they can avoid that. So, I said getting up every hour and moving around, being less sedentary, trying to up their step count. I think once it's there in the front of people's minds, I think they're more likely to then do something about it. I think people like to know why,

not just nanny telling them, you know, you've got to do this. They want to know, well, why? Why should I try and do my 10,000 steps? Why should I not sit and watch daytime television all day? Why should I go upstairs? I think if people know why, I think they're more inclined to try and do that.

That's really interesting. So if someone's listened to this and saying, Janet, you totally convinced me. I want to have all those extra healthy years and I need to like help my immune system to sort of switch off this inflammation. I'm interested in exercise. You've been very clear about this.

I'm interested in food. Do we understand anything about specific types of food that could help to reduce inflammation? So there are specific foods. So I've mentioned the polyunsaturated fatty acids. They're definitely anti-inflammatory. So we know that. They're probably the ones that's got the most evidence.

Vitamin D, that a lot of your viewers will have heard about. We know supports your immune system as well as helping muscle and bones. So that's another one. And then there's others that, you know, your listeners may not have heard of. There's one called astaxanthine, which is the red color in salmon and in vegetables. And that also is anti-inflammatory.

So yeah, we do know quite a bit, but probably the most work has been done on the polyunsaturated fatty acids. So what I'm understanding is firstly, like these, you know, sort of these healthy fats you're describing that you get in sort of oily fish and olive oils and things like this are really good. But also we now understand that what do you call it? Astaxanthine. Which is actually, you said like a red colouring, like red food. Yeah, it gives salmon the red red color in like red foods.

Yeah, it gives salmon the red color and red color in foods. And we actually know that that specifically has anti-inflammatory properties. That's amazing, I'd never heard that. So there's a lot we can do with exercise, there's a lot we can do with food. Is there anything else that affects inflammation? And I guess one of the things in my mind is like,

there's so much discussion about being somehow more mindful and less stressed and how stressful life is. Is that all hocus pocus or is there any science in that? No, not at all. So we do know that stress in the body will certainly again promote some of the features that we think of as aging. So cortisol, I've mentioned quite a few times, is what we call catabolic, so it breaks tissues down and it's rolling the body is part of your flight and fight response. So if you're in danger when we were the hunter-gatherers you

need to be able to run away from that saber-toothed tiger. So you up your cortisol, you up your adrenaline and if they're there for a short length of time then they're good, they break down your tissues they produce energy but it's like the inflammation you don't want them there for a long time so when they're there for a long time then they can carry on breaking the tissues down increasing your chance of osteoporosis and sarcopenia so stress yeah when it's chronic it's like it's it's again it's like the inflammation. Short-term, acute, you need it biologically, but long-term, you really don't want it around, and that cortisol also suppresses your immune system.

It sounds much worse than I would have expected. You're saying like, literally, I'm really stressed for a long period of time, and it's going to break down my muscles and all sorts of cells in my body. And again, most of your viewers will recognise that when you're stressed, you're more susceptible to infections. If you're going through a stressful period, you get coughs and colds and all manner of things because your immune system is suppressed. One of the reasons it's worse as you get older is, A, your immune system doesn't function as well as you get older, but also, like everything else in the body, there's balance. So when you have a

stress, you make the stress hormone cortisol, but you also make another one called DHEA, and that's pro-building your muscle up, it supports your immune system. But as you get older, you go through a thing called the adrenopause. So your viewers will have a bit of menopause, which is losing your sex hormones. So adrenopause, you'll lose the ability to make DHEA. So you haven't got the counterbalance to the cortisol anymore. So you're out of kilter. So anytime you have a stress as an older adult, you're making the cortisol but you can't make as much DHEA to balance it. So you're more stressed as it were, hormone wise. And when does that start to happen?

30 years old, I'm afraid. Yeah, about 30 years old you start to go through the adrenal pause. Oh, so this happens really early in life? It's one of the earliest pauses. So anyone listening to this hope? And males and females. It's a gradual decline, but by the time you get to 70, you know, you've only got about 10% of the DHEA that you had as a 20 year old.

Only 10%. Yeah. And so that means this cortisol, which you're describing. Which you make all the time. That doesn't decline. Your ability to make cortisol stays with age, but DHEA, you lose your ability to make it. So you're good at getting stressed, but worse at getting unstressed. Yes.

Is that what you're saying? Yes. That's fascinating. And you're then describing how this cortisol also directly has these like bad impacts. It stresses the immune system, breaks tissues down. And again, just as you said about inflammation, like short term to be able to stress is fine. But long term it's a real problem. Yes.

And does this also then tie back to this description about why you know you might get flu in your 70s or 80s and you can end up in hospital but when you're in your 20s. That's right. You can't make the counterbalance and you've got an immune system that doesn't function as well anyway as you get older. So the two together are just killers. Last thing that I haven't heard you mention is sleep.

Yeah. Does it matter? It does. Again, it's a relatively new area, thinking about the impact on aging, but we do know that there's a sweet spot. It's like a U-shaped curve, so if you sleep for approximately six and a half, seven and a half hours, then your risk of dying is at the lowest. But either end, so if you're down at four to

five hours or if you're over at ten hours, then you've got a higher risk. So too little and too much sleep are bad for you and the sweet spot is about six and a half and a seven and a half hours and again that that low level at four to five hours again is a stressor you know you're awake because you've got higher levels of this cortisol it's your awakening hormone there's lots of things in the body but it's the awakening hormone So when you wake up in the morning, it's because you've had a surge in cortisol. And as you get older, unfortunately,

you tend to wake up earlier because you've got that cortisol, but you haven't got the counterbalance as well. So you wake up earlier, you don't sleep for as long, and your sleep quality isn't as good either. So you tend to be waking up constantly in the night. And does the sleep have any direct beneficial impact on inflammation? And I'm just asking because I feel like when you have a good night's sleep somehow you just wake up feeling refreshed

everywhere. To be honest that needs looking at. There's really not enough. We did a tiny study years ago but it was probably too small to find anything trying to see if there was any correlation between sleep duration and inflammation, but it needs to be done on a bigger study. I mean, part of what I'm taking away from this is, we know a lot about how important inflammation is for our health, but it sounds like there's a lot of things that we don't yet really understand in terms of how this inflammation is being controlled. Exactly. We need to understand more about the precise causes in each person, because they will vary.

In one person, it might be because they're not being physically active enough. In another person, it might be their diet. It's going to be different. And how they deal with that, some people might have really good off switches, and so they can, as it were, offset their lifestyle choice or whatever they're doing. And other people might not have really good off switches and they're gonna be much more susceptible. And Janet, is there a future where I'm gonna be able

to go to see my doctor and get medication to solve the fact that my inflammation is too high? Oh gosh, that's a good question. Yeah, there is, there's certainly work in that area. Some of your viewers may have heard of things, the polypill, where they're trying to think, is there a medication? And the polypill contains things like statins, like antihypertensives, folate to help you regenerate tissues,

and certainly anti-inflammatories in there. So, there's certainly some of the medical profession that do want to promote that idea. And certainly there's merits there. And statins, we haven't spoken about really drugs at all but statins, we did some research a few years ago now showing that they correct one of the defects in the immune system so they make a cell called a neutrophil which kills bacteria, they make it work better and they also reduce the inflammation when a person's got pneumonia. So statins as well as keeping your cholesterol down also seem to promote a good immune system. Yeah I think in the future there could be pills that will do it and won't have the side effects. With the drugs

you've always got to think about the side effects whereas diet and exercise, hey what's not to like about them? And it sounds like there isn't like a magic breakthrough drug that's just we're all going to be hearing about next year. Well, that's really interesting. So there are quite a few trials going on looking at some different drugs that tackle different size aspects of aging processes. So looking at the core aging processes. Some of them are existing drugs, again one is metformin which is used to treat type 2 diabetes. There are others that are looking more at things in the diet that might be able to tackle or cause anti-aging processes, so you know

there are studies with those as one component called quercetin, another one called fisatin, and what they do is they stimulate anti-aging processes. So those trials are ongoing, we just don't have the answer yet. But give it five or 10 years and that's the way the field is going, I think.

Janet, you've offered so much different great advice, which is great, but also maybe a little overwhelming. Let's say I wanted to share one piece of advice with my sister, who I'm actually talking to you later today, and it's like something she could do tomorrow. What would it be? For me, it would be increase your step count, be more physically active. That would be the number one thing. Number two would be reduce your sedentary time.

So very closely linked. That would be my advice. Because I think it's something that everybody can do. And as I said, don't worry about your current level, just do a bit more. I would like to try and do a quick summary and Janet please just correct anything that I've got wrong. The thing that springs straight to my mind is this amazing study you did that said,

when people got up to 10,000 steps a day, you saw no inflammation. And that is like a very achievable target. And a lot of people, particularly people who are now working at home, you can be way, way below that. But that is manageable. That's not saying you have to pump iron for two hours or run a marathon or indeed fast for 36 hours. The second thing that I'm amazed by is this idea that my body fat creates inflammation and that we now understand that one of the reasons

why being overweight is so bad for your health is because it's actually pumped, you know, it's actively doing something. It's not just this dormant thing as I'd understood it. And the third thing that I'm really shocked by is that when I'm stressed, I'm creating this cortisol, it's actually breaking down my muscles and damaging my bone, which probably only makes me even more stressed, which is always a danger of knowing a little bit more about what's going on.

But that's amazing. And what you've been studying all this time is the way that all of this, your diet, you know, being too sedentary is driving higher inflammation. And we now know that this inflammation is sort of central to why we age, you know, heart disease, dementia, and indeed even why it slows our muscle growth, which also causes us problems as we get old. And that the issue is not just switching inflammation on, it's the fact that we're losing this ability to switch it off.

And so it's sort of permanently like on at a low level instead of being switched off. And that's a really big problem because it's suppressing our immune system and causing all of these problems. And that as our immune system gets older, we lose the ability to fight infections and this inflammation is just making that worse, which again means that when you get sick in the winter, As our immune system gets older, we lose the ability to fight infections

and this inflammation is just making that worse, which again means that when you get sick in the winter, suddenly you're getting sicker for longer than before. There are other things you were saying that can both help and hurt. So you said for many women going through menopause, for example, is a big shift in your inflammation rises because you've lost the estrogen.

But on the other hand you know if you can build up more muscle whoever you are you can reduce inflammation and therefore I think your key tips you're saying is make sure you're doing exercise even just steps like just whatever you are if you can do more steps tomorrow you're going to really make a difference but also don't just think about it as exercise and then being stationary, which I think I'm often guilty of. I'm saying, well, I've done the gym, so now I can just sit down for the rest of the day. And you're saying it doesn't work.

You need to get up every hour, you said. And if you can design your life somehow to achieve this. So the good thing for me is I'm addicted to drinking tea. So one of the things I've done is like, my studies at the top of the house and the kettles at the bottom of the house that forces me to go up and down. And what you're saying is I might actually be fighting my inflammation just because you're going up and down stairs and you're reducing your sedentary time. I'm the same, my studies in

the loft and the kitchen's down two floors below. Whatever I do, I mustn't put a kettle up next to the study. No, definitely not. That's how I look after myself. And don't go to a bungalow. You yourself are doing something rather remarkable, which is fasting for more than 24 hours because you think this is sort of switching on all of these systems to keep you younger. And I guess the other big thing that we talked about was food and that we know that the diet

not only is improving our microbiome, but is having this big impact on our inflammation, reducing the inflammation. And it's many of the classic things that we talk about on this podcast, but it was really interesting that you focus a lot on the healthy fats that are supporting us, like the olive oil and the oily fish. And indeed it might be that there's this red color that is in salmon and certain vegetables might itself be one of the things that's also contributing. So anything important that I missed there Janet? I know, I don't think so. I think you've captured it all, yes.

My takeaway is we now understand a lot about what is making us age and it's not just inevitable that basically by the lifestyle choices we make we can have a very big impact on... Yeah, you can really slow it down. You can't stop it, but you can really slow it down. Now, if you listen to the show regularly, you already believe that changing how you eat can transform your health, but you can only do so much with general advice from a weekly podcast.

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