Thursday, March 28, 2024

Marie Murphy | Leading the World in Physical Activity Research

by Editor

Professor Marie Murphy is one of the world leaders in research on physical activity. Her research on walking underpins  much of our public health guidance

I caught up with Marie, literally down by the Trackside.

Marie Murphy: I started life as a physical education teacher and I taught for a couple of years in Northern Ireland and in London. I was very interested in doing further study and learning a more about the physiology and how the body responds to exercise, so I did a Master’s and a PhD at Loughborough University.  During that time I became more interested in postprandial lipemia.  In other words, how your blood fats change when you exercise and how that might be linked to cardiovascular disease.  I ended up working first in Ulster University, or University of Ulster as it was then, and my research has evolved over years to look specifically at physical activity rather than exercise.

We think of exercise as being something quite vigorous, something quite structured in your day, whereas physical activity, the walking, stair climbing or all the things that you might do to get a little bit of movement, was what interested me.  Over the 30 years of my research career I have become more interested, not just in the physiological changes, but in how we get people to change their behaviour.  We know exercise is good and that physical activity changes your risk profile for about 23 different diseases but, how do we encourage behaviour in people who don’t exercise, or who don’t like physical activity?  That’s been my focus for the last 10 or 15 years and, in my move to University of Edinburgh, I’m now leading a group of researchers in physical activity for health.

DMacA: Loughborough must have been a fantastic environment and you must have met some really inspiring people.

MM: Loughborough was probably the light that lit the fire of research for me. I was really fortunate to work with two greats.  Clyde Williams was the professor and he became the director of studies on my PhD, and Professor Adrianne Hardman, who was the first person to look at walking. She and Jeremy Morris wrote the seminal paper on walking in health because, prior to the early 90s, medics and others dismissed walking because it wasn’t vigorous enough. Because it wasn’t running, aerobics, or 20 minutes of hard work, it was dismissed as not worth  promoting whereas now, after 30 years, walking has become the cornerstone of Public Health or physical activity for Public Health. Adrianne Hardman and Jeremy Morris were probably responsible for that.

DMacA: Your interest in walking is fascinating.  How much walking should you do, how do you walk, how vigorous should it be?

MM:  I hope you have all day now because this is where I get on my hobby horse!  All walking is good for you, that’s the first thing.  And for the vast majority of the population it’s something that we do every day, and that we can do, and it doesn’t require any particular skill.  Most of us walk from about a year old onwards so, unlike other types of physical activity, walking is ubiquitous. It’s something that can appeal to anyone. It doesn’t have social barriers, it doesn’t have cost barriers, you don’t need a gym, you don’t need equipment so, to me, it is the perfect form of exercise or the perfect form of physical activity.

How should you do it? Any walking is good no matter what you do. We’ve heard recommendations such as 10 000 steps but, essentially if you can do 150 minutes a week which translates to about 20 or 30 minutes a day, that’s meets the current guidelines.  But, as I’ve always said, and it came initially from Professor Stephen Blair at the Cooper Aerobic Institute, some is good but more is better. There’s no amount of walking that is bad for you.  You should do some but, if you can do more, that’s better. I would encourage people if they can, to walk a little more briskly because, while  ‘dandering’, or a ‘window shopping’ pace is okay and it gives you some benefits, if you really want to get the benefit, then raising the heart rate, getting the blood beating faster, is about walking briskly.  So I’d say to people, walk at a pace as if you’re a bit late for a meeting, or you’re a bit late for a bus, and at a pace where you are breathing a bit heavier than normal but at a level where you are still able to carry on a conversation.

DMacA: I’m feeling a little guilty filming this down at the track side because it’s usually associated with young fit athletes, but walking is exercise for everyone.  What about exercise as we get older?

MM: That’s where walking comes into its own because, like you, I’m still an avid runner and have always been a sports person.  But, as you age, because your maximum capacity for exercise or your VO2 max declines, you aren’t going to be able to run as long or play vigorous sport, but walking still allows you to get the level of stimulus to maintain health benefits.  And, importantly, when walking you’re much less likely to get injured.  Running causes injury, many sports cause injury but, it’s very rare to find somebody getting a musculoskeletal injury just from walking.  If they get injured walking, it’s because of traffic or the environment or the surface, it’s not because of the act of walking itself because walking is, of course, low impact.  You’re not leaving the ground and therefore you have a much less risk of injury, particularly joint injury.

DMacA: How do we integrate walking into the public health message, how do we sell it?

MM: There are a couple of different strands to that.  First, all walking is good for you so, if you can, build walking into your day in short bouts.  My PhD was about whether you could split walking sessions and, when I started my career, we thought you had to exercise continuously for 20 minutes and if you stopped at 19 minutes to tie your shoe, you had to start again. We now know, through my research and that of many others, that you can split it up in small bouts, and it adds up like loose change.  If you collect all your loose change at the end of the day, after a couple of weeks you’ve got quite a lot.  Same with walking, a minute here a minute there, walking from the bus to your place of work, or walking your dog.  All adds up to a quantum which is probably enough to keep you healthy.  My message would be that if time is a key barrier, if you don’t have enough time to exercise or you don’t think you’re fit enough, or you don’t think you’ve got the motivation, these small little bits can add up. 

Fitbits, step counters, pedometers and other technology can be good because, if you’re about to sit down for the evening and collapse on the sofa, you can have a quick look at how many steps you have completed and if you haven’t had enough, a quick walk around the block, or a quick walk out to a friend’s house and back, or to the park and back, will probably be enough to allow you to finish your day saying ‘okay, well at least I did some walking today.

DMacA: You achieved a huge amount in your research career. Where do you think research is going in physical activity?

MM: I still think we have a lot to do to figure out behaviour change.  We know changing habits and changing behaviours is really difficult and there’s more to know.

For me, it’s how do we change the least active people.  People like you and I enjoy physical activity, we like it, we will make time for it because it gives us great enjoyment and a good return, but there are a bunch of people who see exercise and physical activity the way I might see going to the dentist- something that I’ll avoid and put off.  How do we change their perception?  The key is to find a form of physical activity and a location for physical activity, like this green space or blue space, where they gain the mental health benefits, the elevation of mood, they feel good, and they remember that.  And the next time they’re thinking, oh I can’t be bothered, I’m tired, it’s dark, it’s raining, they will recall how it felt when they finished their activity. 

Secondly, I think we’re going to get much better at measuring physical activity. At the moment, if we want to find out about physical activity, we tend to ask people how much they have done in the last week or so but we all know that that self-report is not particularly good.  It’s not particularly reliable and it’s subject to bias.  In general, we tend to tell people what we think we should do, rather than what we did.  With the pervasiveness of smartphones and fitbits and accelerometers, and they’re becoming cheaper, I think there will be a time, and possibly not in my lifetime, where we will be able to look at device measured physical activity and know who we should target and how we should target them.

We will be able to identify the least active people and know how to change their behavior so that ultimately more people will be more active more often.

DMacA: For those who’ve been inspired by what you’ve said so far, how can they begin their research career and further develop their research career. And I ask you not just as an individual professor but as someone who has looked after doctoral students in university right across the whole span of research.

MM: I think it starts with passion.  And if you have a passion for physical activity, and we’re blessed in the UK and elsewhere, as we have lots of good research units, its about linking to one of those units through doing your Degree there, your Master’s, and we have lots of opportunities for paid PhD’s.  After that, it’s about working with policy makers and practitioners and clinicians so that you identify the right questions.  Because, research is only useful if it answers questions that need answered.  It’s the idea of co-producing research, talking to the clinicians, talking to patients, talking to populations, and trying to find out what is it that we need to know and using that as the stimulus or the basis for that research.

DMacA: Marie you used a word there that describes your career beautifully.  Thank you for sharing your ‘passion’ for physical activity. 

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