Challenging old limits: the science of healthy ageing

At Manchester Metropolitan University, experts in muscle and bone are working to change minds. Because, with a vast body of pioneering work on the biomechanics and physiology of older people, our researchers are working to defy a stereotype of ageing shaped and reinforced by everything from soap operas to healthcare policy.

How we think about age

With every stage of the human life course, from infancy and adolescence, into maturity, middle age and old age, there are certain expectations to live up to. Children learn, teenagers go through the rollercoaster of puberty, adults settle down to start a family. Finally, the stereotype dictates that it’s time to slow up, sit down and give way to infirmity.

Of course, age does take its toll. Bones and muscles weaken, balance fades and the body’s ability to heal recedes. The risk of falls and fractures grows. People lose what the World Health Organization refers to as their ‘intrinsic capacity’.

What is changing is when and how this happens, because people are living much longer. According to the Office for National Statistics, life expectancy for women has increased from around 65 years in 1931 to almost 83 years in 2011. Traditional ideas of old age are getting tired.

The enduring image – sitting immobile at home – is an invitation to settle into a sedentary lifestyle. Expecting frailty to come can, in fact, hasten its arrival. So, across hundreds of research papers and projects, a group of experts at Manchester Met are challenging that stereotype, charting a healthier way of ageing and, in the process, making an impact on millions of people’s lives. 

The difference between living longer and surviving longer

The dramatic rise in average life expectancy is a success story of scientific discovery, welfare provision and public health – leaps in medical treatments, wider access to healthcare and more nutritious food on our plates. But with an ageing population comes growing health and social needs, from medicines and hospital beds to nursing homes and retirement benefits.

As outlined in the UK’s Industrial Strategy: “The prospect of longer lives will require people to plan their careers and retirement differently.” However, while the age of retirement is creeping up, it hasn’t kept pace with longer lifespans.

Yet a focus on broader political topics such as pension benefits or social care obscures more day-to-day issues around quality of life. As Dr Gladys Pearson, Director of Manchester Met’s Musculoskeletal Science and Sports Medicine (MSSM) Research Centre, says, “For many people, getting old means living a life that is less active, less social and less fulfilling than before. We almost expect ageing to be a downward stream, pulling us into frailty.”

Along with her colleagues at the MSSM Research Centre, Dr Pearson works to find healthier ways of ageing. The result is policy-shaping, life-changing research that shows how to limit the slide into frailty, giving older people a greater chance of independence, confidence and happiness – with a far-reaching, knock-on impact for wider society.

Bone, muscle and the mechanics of human movement

Dr Pearson’s academic career goes back more than 20 years. While her first interest was pharmacology, research opportunities pulled her away from the chemistry of physiology and toward the mechanics of bone and muscle. Today, it’s unlikely you’ll meet anyone so infectiously enthusiastic about the way muscles and tendons work.

As the Director of the Centre, Dr Pearson leads an extraordinary concentration of experts in the way humans move – with more than 40 members and around 40 PhD researchers – having published around 150 peer-reviewed papers a year for the last two decades.

It’s a broad group that represents a vast range of expertise, from the molecular to the societal. Much of the group’s impact comes not just from that depth and range of knowledge, but in how they connect and combine these different specialities – with colleagues across the Centre, across the University and even across the world.

This kind of collaboration helps the Centre’s experts in physiology, biomechanics and motor cognition bring new tools and perspectives to their work: harnessing artificial intelligence to help measure exercise patterns, using advanced mathematics to calculate tendon stiffness under different tensions, and bringing sociology and physiology together to frame their findings in terms of the socio-economic factors.

The results of those partnerships have huge implications – as Dr Pearson puts it: “The work we are doing is helping us separate the naturally occurring issues of ageing and what comes down to preventable co-morbidities – other conditions common in older people, like arthritis, diabetes or cardiovascular issues. Crucially, it’s about the impacts that we can halt, or even reverse.”

Questioning the questions

The MSSM Research Centre represents a vast, eclectic variety of specialisms. Across it all, there is a common thread that binds the body of work together: an unwillingness to accept received wisdom. While every research project at Manchester Met is about digging deeper into a given subject, the researchers’ work repeatedly focuses upon challenging old assumptions – it’s about first testing the test.

As Dr Pearson says: “So much of our work produces valuable results because it starts with interrogating the methods we use to collect and analyse our data.”

For instance, a paper investigating how muscles become smaller and weaker in older age – a type of atrophy called sarcopenia – also examined different methods of medical scans. While the results confirmed that the average person will lose around 30% of their leg muscle mass by the time they reach 70-80 years old, it also compared two scans – DXA (dual-energy X-ray absorptiometry) and MRI (magnetic resonance imagery) scanning – and found that the first type wasn’t as accurate for measuring muscle loss.

Meanwhile, in a project focused on neuromuscular research (investigating the link from the central nervous system to the muscle) experts from the Centre pioneered an artificial alternative to the liquid or gel used in petri dishes and test tubes in the lab, offering an ethical replacement for the materials usually made from horses or cows.

Even the simple questionnaire has been challenged. While it’s a common tool for gathering the kind of personal data that is vital for many studies, as Dr Pearson explains, it has a major potential flaw: the person filling it out. “Consciously or not, people sugar-coat the truth about their behaviours – it’s human nature. If I ask a patient how often they get up from their chair or how they’ve walked that day, they might worry that they’ll be seen as lazy and so beef up their numbers.” To counteract this, the researchers opted to use an accelerometer strapped to the subject’s leg, in a study which then used machine-learning to help interpret the results, producing a much less subjective measurement. “We then found that our subjects were overstating their exercise fourfold – which means even light exercise is more significant than we thought.”

Measuring someone’s strength comes with similar issues. “If I ask someone to lift the heaviest weight they can, they might not try their hardest – maybe they’re nervous about being part of the research, or they’re in a hurry to get it done so they can leave.” Instead, the research team bypassed the emotional element by using electric stimulation to test tension on tendons. Though, as Dr Pearson points out, there’s still room for a little human compassion: “It can be a little uncomfortable, painful even, but it gives us much more valuable information. And most of our subjects come back and take part in studies – a cup of tea and a good chat usually helps!”

This approach is itself pioneering – up until recently, tendons were only tested outside the body, through biopsies or post-mortems. A team at Tokyo University first introduced a method for testing tendons in vivo (inside the body), which Dr Pearson and her team have adopted and adapted for their own research. With various projects that have tested tendons while still part of the whole musculoskeletal system, researchers at Manchester Met have dispelled long-held misunderstandings about the stress on tendons under force.

Findings that fight frailty

While the innovative techniques and intelligent approaches are achievements in their own right, they are a means to an end, opening doors to a better understanding of the impact of ageing.

Dr Hans Degen’s work in the lab, for instance, has provided concrete evidence of how sarcopenia afflicts muscles as they age. As he says: “We could even see the age-related slowing of muscles at the molecular level, where our changing biochemistry impairs muscle cells from what’s called ‘cross-bridge cycling’. Our work showed that, as we age, we experience muscle fatigue right down to single cells.”

Another project created a model for ‘optimal ageing’ by examining a large group of elite master athletes – aged between 35 and 90. The research found that even the fittest in society still suffer a loss of muscle mass, strength and bone mass. In particular, the study showed that this group’s postural stability was no better than non-athletes – suggesting that specific balance training is valuable for older people regardless of their activity levels.

Meanwhile, the project that harnessed DXA and MRI scanning to investigate sarcopenia not only quantified the muscle mass people lose in their legs as they grow older, but also proved that an active lifestyle with specific exercises could combat that loss – preserving the muscles, maintaining their ‘intrinsic capacity’ and protecting wider health.

The implications of one piece of Dr Pearson’s work with tendons are no less important. In experiments comparing men’s and women’s tendons, her research showed that they react differently to the same ‘response magnitude’ – in other words, stretching both the same way creates the opposite kind of stress. In the real world, that means an exercise programme developed with men in mind could be unsuitable, if not actively harmful, for women.

The relationship between research results and real-world relevance is not always such a straight line. For instance, the Centre’s researchers learned a lot about the nature of muscle wastage after long periods of inactivity by investigating subjects that were far from elderly or infirm: astronauts in space. As part of a multi-year study of astronauts from NASA and its Japanese equivalent JAXA, experts from Manchester Met are examining the impact of, and rehabilitation from, a simulated microgravity environment, as this offers parallels for the impact of ageing.

Translating insight into impact

With every project, with all the experiments and measurements that go into the hundreds of research papers, the team at Manchester Met have built a clearer picture of healthy ageing. Again and again, the process of investigating muscle and bone to quantify the impact of age offers conclusions with life-changing potential in the real world.

For Dr Pearson’s project using accelerometers and machine learning to measure habitual physical behaviour, there was another component – a watch that vibrated every so often, reminding the subject to stand up and move around. This work provided the first rigorous evidence that replacing sedentary behaviour with even light-intensity activity can combat osteoporosis in older people. “We know instinctively that exercise is good for us, but lots of people are put off when you call it exercise. What we found meant that even simple things, like getting on your feet more and walking a little as part of your day – what we sometimes call ‘exercise by stealth’ – make a significant difference for your bone health.”

The Centre’s work offers similarly profound conclusions around strength and balance. With a body of work around strength training, including a study on exercising with different loads and research into a high-speed type of training known as Plyometrics, they have shown that the effects of ageing can be slowed down or even reversed in most of the body’s physiological systems. And, having proved that imbalance and sway afflicts all older people, including elite athletes, the researchers have also shown that balance training is vital for reducing the risk of falls and fractures. Training can save people from significant injury or worse, as Dr Pearson explains: “Lots of people might not realise how bad a fall can be – it almost sounds innocuous. But when your bones are weaker, a fractured leg or hip can lead to a long stay in hospital. Then that fall can be the start of more serious decline.”

Today, all these conclusions and insights gathered over the years are making a genuine, life-changing difference to older people across the UK. The group’s work has provided crucial evidence for the UK Chief Medical Officer’s 2019 Physical Activity Guidelines, shaped falls-prevention work at local government level and influenced exercise and training guidance given to thousands of master athletes. Which means there are decades of Manchester Met work distilled into each moment a GP offers advice about physical activity, or a patient steps out for a walk with renewed confidence, or a runner takes the time to do their balance exercises. Put simply, it’s research that’s shaping lives every day.

What’s next?

Frailty isn’t a single condition that can be treated, but a combination of all those factors that the Research Centre explores. Issues around bone health, muscle mass and balance all contribute to the weakness, exhaustion, slowing down and weight loss that age can bring.

While the researchers have made impressive strides, there is no simple fix. New technology offers tantalising possibilities – like digitisation connecting patients and clinicians remotely, or artificial intelligence providing automated care. As Dr Pearson explains: “There are all sorts of possibilities for tools to monitor people’s health in the home, or to help clinicians provide more individualised care. I’ve recently heard discussions about virtual wards – where patients have the same systems and staff that they would in hospital, but without the physical building, and about how we can harness volunteering as a tool to promote healthy ageing – almost like having patients support each other. There are exciting innovations just around the corner.”

The science of healthy ageing is a pursuit without a finish line. Instead, there are aspects of human muscle and bone yet to be discovered, there are more misconceptions and methods to be challenged, and there are more insights to be developed about the way we age. Which means, for Dr Pearson, there may be more tendons to test, more projects to lead and more cups of tea to give out to her test subjects.