̽��ֱ�� of Cambridge - exercise

Older adults who remain more active have a better quality of life, study finds

cjb250 — Tue, 04 Jul 2023 08:00:19 +0000

̽��ֱ��same was also true for increases in the amount of sedentary time, such as watching TV or reading. ̽��ֱ��researchers say this highlights the need to encourage older adults to remain active.

Physical activity – particularly when it is moderate-intensity and raises your heart rate – is known to reduce the risk of a number of diseases, including heart disease, stroke, diabetes and cancer. ̽��ֱ��NHS recommends that adults do at least 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity a week. Older adults are also recommended to break up prolonged periods of being sedentary with light activity when physically possible, or at least with standing, as this has distinct health benefits for older people.

A team led by researchers at the ̽��ֱ�� of Cambridge examined activity levels among 1,433 participants aged 60 and above using accelerometers. ̽��ֱ��participants had been recruited to the EPIC (European Prospective Investigation into Cancer)-Norfolk study.

Alongside this, the team also looked at health-related quality of life, a measure of health and wellbeing that includes pain, ability to care for yourself and anxiety/mood. Participants were given a score between 0 (worst quality of life) and 1 (best) based on their responses to a questionnaire. Lower quality of life scores are linked with an increased risk of hospitalisation, worse outcomes following hospitalisation, and early death.

Participants were followed up an average of just under six years later to look at changes in their behaviour and quality of life. ̽��ֱ��results of the study are published in Health and Quality of Life Outcomes.

On average, six years after their first assessment, both men and women were doing around 24 minutes less moderate-to-vigorous physical activity per day. At the same time, the total sedentary time increased by an average of around 33 minutes a day for men and around 38 minutes a day for women.

Those individuals who did more moderate-to-vigorous physical activity and spent less time sedentary at their first assessment had a higher quality of life later on. An hour a day spent more active was associated with a 0.02 higher quality of life score.

For every minute a day less of moderate-to-vigorous physical activity measured six years after the first assessment, quality of life scores dropped by 0.03. This means that an individual who spent 15 minutes a day less engaged in such activity would have seen their score drop by 0.45.

Increases in sedentary behaviours were also associated with poorer quality of life – a drop in the score of 0.012 for everyone minute a day increase in total sedentary time six years after the first measurement. This means that an individual who spent 15 minutes a day more sitting down would have seen their score drop by 0.18.

To put the results into a clinical context, a 0.1 point improvement in quality of life scores has previously been associated with a 6.9% reduction in early death and a 4.2% reduction in risk of hospitalisation.

Dr Dharani Yerrakalva from the Department of Public Health and Primary Care at the ̽��ֱ�� of Cambridge said: “Keeping yourself active and limiting – and where you can, breaking up – the amount of time you spend sitting down is really important whatever stage of life you’re at. This seems to be particularly important in later life, when it can lead to potentially significant improvements to your quality of life and your physical and mental wellbeing.”

Because the team measured physical activity and sedentary behaviour at different points of time, they say they can be reasonably confident that they have shown a causal link – that is, that quality of life improves because people remain more physically active, for example.

Dr Yerrakalva added: “There are several ways in which improvements in our physical behaviours might help maintain a better quality of life. For example, more physical activity reduces pain in common conditions such as osteoarthritis, and we know that being more physically active improves muscle strength which allows older adults to continue to care for themselves. Similarly, depression and anxiety are linked to quality of life, and can be improved by being more active and less sedentary.”

̽��ֱ��EPIC-Norfolk study is funded by the Medical Research Council and Cancer Research UK.

Five ways to keep yourself physically-active in older age

A brisk daily walk – ideally for around 20 minutes
Gardening
A bicycle ride
Dancing
Tennis

Reference
Yerrakalva, D et al. Associations between change in physical activity and sedentary time and health-related quality of life in older English adults: the EPIC-Norfolk cohort study. Health and Quality of Life Outcomes; 22 June 2023; DOI: 10.1186/s12955-023-02137-7

A reduction in the amount of time spent physically active when adults are over 60 years old is linked to lower quality of life, a Cambridge study of almost 1,500 adults has shown.

Keeping yourself active and limiting – and where you can, breaking up – the amount of time you spend sitting down is really important whatever stage of life you’re at

Dharani Yerrakalva

Peter Kindersley (Centre for Ageing Better)

Family exercising outdoors

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Daily 11 minute brisk walk enough to reduce risk of early death

cjb250 — Wed, 01 Mar 2023 00:29:21 +0000

In a study published today in the British Journal of Sports Medicine, the researchers say that 11 minutes a day (75 minutes a week) of moderate-intensity physical activity – such as a brisk walk – would be sufficient to lower the risk of diseases such as heart disease, stroke and a number of cancers.

Cardiovascular diseases – such as heart disease and stroke – are the leading cause of death globally, responsible for 17.9 million deaths per year in 2019, while cancers were responsible for 9.6 million deaths in 2017. Physical activity – particularly when it is moderate-intensity – is known to reduce the risk of cardiovascular disease and cancer, and the NHS recommends that adults do at least 150 minutes of moderate-intensity activity or 75 minutes of vigorous-intensity activity a week.

To explore the amount of physical activity necessary to have a beneficial impact on several chronic diseases and premature death, researchers from the Medical Research Council (MRC) Epidemiology Unit at the ̽��ֱ�� of Cambridge carried out a systematic review and meta-analysis, pooling and analysing cohort data from all of the published evidence. This approach allowed them to bring together studies that on their own did not provide sufficient evidence and sometimes disagreed with each other to provide more robust conclusions.

In total, they looked at results reported in 196 peer-reviewed articles, covering more than 30 million participants from 94 large study cohorts, to produce the largest analysis to date of the association between physical activity levels and risk of heart disease, cancer, and early death.

̽��ֱ��researchers found that, outside of work-related physical activity, two out of three people reported activity levels below 150 min per week of moderate-intensity activity and fewer than one in ten managed more than 300 min per week.

Broadly speaking, they found that beyond 150 min per week of moderate-intensity activity, the additional benefits in terms of reduced risk of disease or early death were marginal. But even half this amount came with significant benefits: accumulating 75 min per week of moderate-intensity activity brought with it a 23% lower risk of early death.

Dr Soren Brage from the MRC Epidemiology Unit said: “If you are someone who finds the idea of 150 minutes of moderate-intensity physical activity a week a bit daunting, then our findings should be good news. Doing some physical activity is better than doing none. This is also a good starting position – if you find that 75 minutes a week is manageable, then you could try stepping it up gradually to the full recommended amount.”

Seventy-five minutes per week of moderate activity was also enough to reduce the risk of developing cardiovascular disease by 17% and cancer by 7%. For some specific cancers, the reduction in risk was greater – head and neck, myeloid leukaemia, myeloma, and gastric cardia cancers were between 14-26% lower risk. For other cancers, such as lung, liver, endometrial, colon, and breast cancer, a 3-11% lower risk was observed.

Professor James Woodcock from the MRC Epidemiology Unit said: “We know that physical activity, such as walking or cycling, is good for you, especially if you feel it raises your heart rate. But what we’ve found is there are substantial benefits to heart health and reducing your risk of cancer even if you can only manage 10 minutes every day.”

̽��ֱ��researchers calculated that if everyone in the studies had done the equivalent of at least 150 min per week of moderate-intensity activity, around one in six (16%) early deaths would be prevented. One in nine (11%) cases of cardiovascular disease and one in 20 (5%) cases of cancer would be prevented.

However, even if everyone managed at least 75 min per week of moderate-intensity physical activity, around one in ten (10%) early deaths would be prevented. One in twenty (5%) cases of cardiovascular disease and nearly one in thirty (3%) cases of cancer would be prevented.

Dr Leandro Garcia from Queen’s ̽��ֱ�� Belfast said: “Moderate activity doesn’t have to involve what we normally think of exercise, such as sports or running. Sometimes, replacing some habits is all that is needed. For example, try to walk or cycle to your work or study place instead of using a car, or engage in active play with your kids or grand kids. Doing activities that you enjoy and that are easy to include in your weekly routine is an excellent way to become more active.”

̽��ֱ��research was funded by the Medical Research Council and the European Research Council.

What counts as moderate-intensity physical activity?

Moderate-intensity physical activity raises your heart rate and makes you breathe faster, but you would still be able to speak during the activity. Examples include:

Brisk walking
Dancing
Riding a bike
Playing tennis
Hiking

Reference
Garcia, L, Pearce, M, Abbas, A, Mok, A & Strain, T et al. Non-occupational physical activity and risk of cardiovascular disease, cancer, and mortality outcomes: a dose response meta-analysis of large prospective studies. British Journal of Sports Medicine; 28 Feb 2023; DOI: 10.1136/bjsports-2022-105669

One in ten early deaths could be prevented if everyone managed at least half the recommended level of physical activity, say a team led by researchers at the ̽��ֱ�� of Cambridge.

If you are someone who finds the idea of 150 minutes of moderate-intensity physical activity a week a bit daunting, then our findings should be good news. Doing some physical activity is better than doing none

Soren Brage

PublicDomainArchive (Pixabay)

Feet walking on gravel

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Pedestrians choose healthy obstacles over boring pavements, study finds

ta385 — Mon, 05 Dec 2022 08:45:00 +0000

Millions of people in the UK are failing to meet recommended targets for physical activity. Exercising 'on the go' is key to changing this but while walking along a pavement is better than nothing it causes no significant increase in heart rate so only qualifies as mild exercise. Walking also fails to significantly improve balance or bone density, unless it includes jumping, balancing, and stepping down.

But would adults opt for such ‘fun’ routes if given the choice? A ̽��ֱ�� of Cambridge-led study published today in the journal Landscape Research suggests that with the right design, most would.

Previous research on ‘healthy route choices’ has focused on people’s likelihood of walking instead of using transport. But this study examined how likely people are to pick a more challenging route over a conventional one and which design characteristics influenced their choices.

Lead author, Anna Boldina, from the ̽��ֱ�� of Cambridge’s Department of Architecture, said: “Even when the increase in level and extent of activity level is modest, when millions of people are using cityscapes every day, those differences can have a major positive impact on public health.”

“Our findings show that pedestrians can be nudged into a wider range of physical activities through minor changes to the urban landscape. We want to help policy makers and designers to make modifications that will improve physical health and wellbeing.”

Boldina began this research after moving from Coimbra in Portugal – where she found herself climbing hills and ancient walls – to London, which she found far less physically challenging.

Working with Dr Paul Hanel from the Department of Psychology at the ̽��ֱ�� of Essex, and Professor Koen Steemers from Cambridge, Boldina invited almost 600 UK residents to compare photorealistic images of challenging routes – variously incorporating stepping stones, balancing beams, and high steps – with conventional pavements.

Participants were shown images of challenging and conventional tarmac routes and asked which route they would choose. ̽��ֱ��researchers tested out a range of encouraging / discouraging parameters in different scenarios, including crossing water, shortcuts, unusual sculptures and the presence / absence of a handrail and other people. Participants were asked to score how challenging they thought the route would be from 1 (as easy as walking on level tarmac) to 7 (I would not be able to do it).

Eighty per cent of the study’s participants opted for a challenging route in at least one of the scenarios, depending on perceived level of difficulty and design characteristics. Where a challenging option was shorter than a conventional route, this increased the likelihood of being chosen by 10%. ̽��ֱ��presence of handrails achieved a 12% rise.

Importance for health

̽��ֱ��WHO and NHS recommend at least 150 minutes of ‘moderate’ or 75 minutes of ‘vigorous’ activity spread over a week, including a variety of activities aimed at enhancing bones, muscles, and agility to stay healthy. In addition, adults over 65 are advised to perform strength, flexibility, and balance exercises.

Boldina said: “ ̽��ֱ��human body is a very complex machine that needs a lot of things to keep working effectively. Cycling and swimming are great for your heart and for your leg muscles but do very little for your bone density.”

“To improve cardiovascular health, bone density and balance all at once, we need to add a wider range of exercises into our routine daily walks.”

Psychology of choice

Co-author Dr Paul Hanel said: “Children don’t need much encouragement to try out a balance beam but we wanted to see how adults would respond, and then identify design modifications which made them more likely to choose a challenging route.”

“We found that while embarrassment, anxiety, caution and peer pressure can put some adults off, the vast majority of people can be persuaded to take a more challenging route by paying careful attention to design, safety, difficulty level, location and signage.”

̽��ֱ��proportion of participants who were willing to pick a more challenging route varied from 14% for a particular balance beam route to 78% for a route involving wide, low stepping stones and a log with a handrail. ̽��ֱ��least intimidating routes were found to be those with wide, steady-looking balancing beams and wide steppingstones, especially with the presence of handrails.

̽��ֱ��researchers suggest that routes that incorporate more difficult challenges, such as obstacle courses and narrow balancing beams, should be placed in areas more likely to be frequented by younger users.

̽��ֱ��participants expressed a range of reasons for picking challenging routes. Unsurprisingly, the study found that challenging routes which also acted as short cuts appealed. Up to 55% of participants chose such routes. ̽��ֱ��researchers also found that the design of pavements, lighting and flowerbeds, as well as signage helped to nudge participants to choose more challenging routes. Many participants (40%) said the sight of other people taking a challenging route encouraged them to do the same.

̽��ֱ��participants who picked conventional routes often had concerns about safety but the introduction of safety measures, such as handrails, increased uptake of some routes. Handrails next to one steppingstones route increased uptake by 12%.

To test whether tendency to choose challenging routes was linked to demographic and personality factors, participants were asked to answer questions about their age, gender, habits, health, occupation, and personality traits (such as sensation seeking or general anxiety).

̽��ֱ��researchers found that people of all levels of activity are equally likely to pick a challenging route. But for the most difficult routes, participants who regularly engaged in strength and balancing exercises were more likely to choose them.

Older participants were as supportive of the concept as younger ones but were less likely to opt for the more challenging routes for themselves. Nevertheless, across all age groups, only a small percentage of participants said they would avoid adventurous options completely.

̽��ֱ��study applies the idea of “Choice Architecture” (making good choices easier and less beneficial choices harder) plus “Fun theory”, a strategy whereby physical activity is made more exciting; as well as some of the key principles of persuasion: social proof, liking, authority, and consistency.

Future work

̽��ֱ��researchers hope to run experiments in physical test sites to see how intentions convert into behaviour, and to measure how changes in habits improve health. In the meantime, Boldina continues to present her findings to policy makers.

Critics might question the affordability and cost effectiveness of introducing ‘Active landscape routes’ in the current economic environment.

In response, the researchers argue that installing stepping stones in a turfed area can be cheaper than laying and maintaining conventional tarmac pavements. They also point out that these measures could save governments far greater sums by reducing demand for health care related to lack of exercise.

Reference

A Boldina et al., ‘Active Landscape and Choice Architecture: Encouraging the use of challenging city routes for fitness’, Landscape Research (2022). DOI: 10.1080/01426397.2022.2142204

Up to 78% of walkers would take a more challenging route featuring obstacles such as balancing beams, stepping stones and high steps, research has found. ̽��ֱ��findings suggest that providing ‘Active Landscape’ routes in urban areas could help tackle an 'inactivity pandemic' and improve health outcomes.

Pedestrians can be nudged into a wider range of physical activities through minor changes to the urban landscape

Anna Boldina

Collage imagining a challenging 'Active Urbanism' route applied to Sermon Lane in London

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Mums’ activity levels may depend on number and ages of children

cjb250 — Wed, 16 Nov 2022 19:00:29 +0000

Physical activity – particularly when it is moderate to vigorous – has many health benefits, decreasing the risk of a wide range of diseases from cancer to type 2 diabetes and cardiovascular disease, as well as helping maintain a healthy weight and better mental health.

Evidence suggests physical activity can help parents cope with the daily challenges of being a parent and strengthen relationships with children if they are active together. However, parents tend to be less active than non-parents.

To examine how family composition affected the amount of physical activity mothers engaged in, researchers at the ̽��ֱ�� of Cambridge and ̽��ֱ�� of Southampton analysed data from 848 women who participated in the UK Southampton Women’s Survey. ̽��ֱ��women, aged 20-34 years, were recruited between 1998 and 2002 and followed up over subsequent years. They were given accelerometers to assess their levels of activity. ̽��ֱ��results are published today in PLOS ONE.

Women with school-aged children did on average around 26 mins* of moderate-to-vigorous physical activity per day, whereas mothers with only younger children (aged four years or under) managed around 18 mins* per day.

Having more than one child meant mothers managed only around 21 mins* of moderate-to-vigorous physical activity per day, but interestingly, mums with multiple children all under five years old did more light intensity activity than those with children of school-age.

Less than 50% of mothers met the recommended levels of moderate-to-vigorous physical activity (150 minutes per week), regardless of the ages of their children.

Dr Kathryn Hesketh from the Medical Research Council (MRC) Epidemiology Unit at the ̽��ֱ�� of Cambridge said: “When you have small children, your parental responsibilities can be all-consuming, and it’s often hard to find the time to be active outside of time spent caring for your children. Exercise is often therefore one of the first things to fall by the wayside, and so most of the physical activity mums manage to do seems to be of a lower intensity.

“However, when children go to school, mums manage to do more physical activity. There are a number of possible reasons why this might be the case, including more opportunities to take part in higher intensity activities with their children; you may return to active commuting; or feel more comfortable using time to be active alone.”

Rachel Simpson, a PhD student in the MRC Epidemiology Unit, added: “There are clear benefits, both short term and long term, from doing more physical activity, particularly if it increases your heart rate. But the demands of being a mother can make it hard to find the time. We need to consider ways not only to encourage mums, but to make it as easy as possible for busy mums, especially those with younger children, to increase the amount of higher intensity physical activity they do.”

Professor Keith Godfrey from the MRC Lifecourse Epidemiology Centre and the NIHR Southampton Biomedical Research Centre said: “It is perhaps not unexpected that mothers who have young children or several children engage in less intense physical activity, but this is the first study that has quantified the significance of this reduction. More needs to be done by local government planners and leisure facility providers to support mothers in engaging in physical activity.”

*Note: these are mean averages

Reference
Simpson, RF et al. ̽��ֱ��association between number and ages of children and the physical activity of mothers: cross-sectional analyses from the Southampton Women’s Survey. PLOS ONE; 16 Nov 2022; DOI: 10.1371/journal.pone.0276964

Less than half of mums meet the recommended levels of moderate-to-vigorous physical activity – and mothers of younger children manage to do the least, Cambridge and Southampton researchers have found.

When you have small children, your parental responsibilities can be all-consuming, and it’s often hard to find the time to be active outside of time spent caring for your children

Kathryn Hesketh

triloks (Getty Images)

Family playing frisbee

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Just over half of six-year-olds in Britain meet physical activity guidelines

cjb250 — Thu, 11 Aug 2022 16:00:54 +0000

Physical activity is beneficial for our physical and mental health, but activity levels tend to decrease across childhood and adolescence. Current UK physical activity guidelines recommend that children and young people from ages 5 to 18 years do an average of 60 minutes of moderate-to-vigorous physical activity (such as playing in the park or physical education) per day across the week. For all children, it is also recommended that they keep to a minimum extended periods of sedentary behaviour (such as sitting watching TV).

To investigate how much activity children do in their early primary school years, researchers from the Medical Research Council (MRC) Epidemiology Unit at the ̽��ֱ�� of Cambridge and the MRC Lifecourse Epidemiology Centre at the ̽��ֱ�� of Southampton provided 712 six-year-olds with Actiheart accelerometers, which measured their heart rate and movement. ̽��ֱ��children, who had been recruited as part of the ongoing Southampton Women’s Survey, wore these continually for an average of six days.

̽��ֱ��results of the study are published today in the Journal of Physical Activity & Health.

At age six, children were sedentary for a daily average of more than five hours (316 minutes) and engaged in over 7.5 hours (457 minutes) of low-level physical activity and just over an hour (65 minutes) of moderate-to-vigorous physical activity.

Just over half of the children (53%) met the current UK recommended guidelines, with boys being more likely to reach the target than girls (63% of boys vs 42% of girls).

Dr Esther van Sluijs from the MRC Epidemiology Unit at Cambridge said: “Using accelerometers, we were able to get a much better idea of how active children were and we found that just over a half of six-year-olds were getting the recommended amount of physical activity. But this means that almost half of British children in this age group are not regularly active, which we know is important for their wellbeing and their performance at school.”

When the researchers analysed activity levels by time of day, they found that girls engaged in less moderate-to-vigorous physical activity during the school day at age six. Possible explanations are that girls wear skirts, which may make physical activity more challenging, or that they choose less active options during break times.

̽��ֱ��researchers were able to look at longitudinal data from some children – that is, data recorded over a period of time rather than just a snapshot – and found that compared to at age four, at age six children became more sedentary (on average, around 30 minutes per day more compared to when they were four), but also engaged in an additional seven minutes per day of moderate-to-vigorous physical activity.

Dr Kathryn Hesketh from the MRC Epidemiology Unit at Cambridge added: “This is something of a double-edged sword: children appear to do more moderate-to-vigorous physical activity when they start formal schooling, which is really positive, but they also spend more time sedentary. This may in part be because of the structure of the school day, so we may want to look at ways to reduce sedentary time when children are younger, to prevent that behaviour becoming habitual.”

Professor Keith Godfrey from the ̽��ֱ�� of Southampton commented: “These analyses indicate that new initiatives to promote physical activity must consider the lower activity levels in girls and at weekends. ̽��ֱ��time when children transition into formal schooling is an important opportunity to ensure a much higher proportion achieve recommended levels of activity.”

While based on detailed data collected up to 2012, evidence from national questionnaire based surveys is that children's patterns of activity levels changed little in the years leading up to the COVID-19 pandemic, with widely recognised even lower rates of meeting the Chief Medical Officer guidelines during the pandemic.

̽��ֱ��work was largely supported by Wellcome and the Medical Research Council.

Reference
Hesketh, KR et al. Activity behaviours in British 6-year-olds: cross-sectional associations and longitudinal change during the school transition. Journal of Physical Activity & Health; 11 Aug 2022; DOI: 10.1123/jpah.2021-0718

All averages quoted are mean.

Fifty-three percent of six-year-olds met the recommended daily guidelines for moderate-to-vigorous physical activity in a study carried out pre-pandemic by researchers at the universities of Cambridge and Southampton.

This is something of a double-edged sword: children appear to do more moderate-to-vigorous physical activity when they start formal schooling, which is really positive, but they also spend more time sedentary

Kathryn Hesketh

JW LTD (Getty Images)

Group of children playing tug of war

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Mathematical model predicts best way to build muscle

sc604 — Mon, 23 Aug 2021 04:28:37 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, used methods of theoretical biophysics to construct the model, which can tell how much a specific amount of exertion will cause a muscle to grow and how long it will take. ̽��ֱ��model could form the basis of a software product, where users could optimise their exercise regimes by entering a few details of their individual physiology.

̽��ֱ��model is based on earlier work by the same team, which found that a component of muscle called titin is responsible for generating the chemical signals which affect muscle growth.

̽��ֱ��results, reported in the Biophysical Journal, suggest that there is an optimal weight at which to do resistance training for each person and each muscle growth target. Muscles can only be near their maximal load for a very short time, and it is the load integrated over time which activates the cell signalling pathway that leads to synthesis of new muscle proteins. But below a certain value, the load is insufficient to cause much signalling, and exercise time would have to increase exponentially to compensate. ̽��ֱ��value of this critical load is likely to depend on the particular physiology of the individual.

We all know that exercise builds muscle. Or do we? “Surprisingly, not very much is known about why or how exercise builds muscles: there’s a lot of anecdotal knowledge and acquired wisdom, but very little in the way of hard or proven data,” said Professor Eugene Terentjev from Cambridge’s Cavendish Laboratory, one of the paper’s authors.

When exercising, the higher the load, the more repetitions or the greater the frequency, then the greater the increase in muscle size. However, even when looking at the whole muscle, why or how much this happens isn’t known. ̽��ֱ��answers to both questions get even trickier as the focus goes down to a single muscle or its individual fibres.

Muscles are made up of individual filaments, which are only 2 micrometres long and less than a micrometre across, smaller than the size of the muscle cell. “Because of this, part of the explanation for muscle growth must be at the molecular scale,” said co-author Neil Ibata. “ ̽��ֱ��interactions between the main structural molecules in muscle were only pieced together around 50 years ago. How the smaller, accessory proteins fit into the picture is still not fully clear.”

This is because the data is very difficult to obtain: people differ greatly in their physiology and behaviour, making it almost impossible to conduct a controlled experiment on muscle size changes in a real person. “You can extract muscle cells and look at those individually, but that then ignores other problems like oxygen and glucose levels during exercise,” said Terentjev. “It’s very hard to look at it all together.”

Terentjev and his colleagues started looking at the mechanisms of mechanosensing – the ability of cells to sense mechanical cues in their environment – several years ago. ̽��ֱ��research was noticed by the English Institute of Sport, who were interested in whether it might relate to their observations in muscle rehabilitation. Together, they found that muscle hyper/atrophy was directly linked to the Cambridge work.

In 2018, the Cambridge researchers started a project on how the proteins in muscle filaments change under force. They found that main muscle constituents, actin and myosin, lack binding sites for signalling molecules, so it had to be the third-most abundant muscle component – titin – that was responsible for signalling the changes in applied force.

Whenever part of a molecule is under tension for a sufficiently long time, it toggles into a different state, exposing a previously hidden region. If this region can then bind to a small molecule involved in cell signalling, it activates that molecule, generating a chemical signal chain. Titin is a giant protein, a large part of which is extended when a muscle is stretched, but a small part of the molecule is also under tension during muscle contraction. This part of titin contains the so-called titin kinase domain, which is the one that generates the chemical signal that affects muscle growth.

̽��ֱ��molecule will be more likely to open if it is under more force, or when kept under the same force for longer. Both conditions will increase the number of activated signalling molecules. These molecules then induce the synthesis of more messenger RNA, leading to production of new muscle proteins, and the cross-section of the muscle cell increases.

This realisation led to the current work, started by Ibata, himself a keen athlete. “I was excited to gain a better understanding of both the why and how of muscle growth,” he said. “So much time and resources could be saved in avoiding low-productivity exercise regimes, and maximising athletes’ potential with regular higher value sessions, given a specific volume that the athlete is capable of achieving.”

Terentjev and Ibata set out to constrict a mathematical model that could give quantitative predictions on muscle growth. They started with a simple model that kept track of titin molecules opening under force and starting the signalling cascade. They used microscopy data to determine the force-dependent probability that a titin kinase unit would open or close under force and activate a signalling molecule.

They then made the model more complex by including additional information, such as metabolic energy exchange, as well as repetition length and recovery. ̽��ֱ��model was validated using past long-term studies on muscle hypertrophy.

“While there is experimental data showing similar muscle growth with loads as little as 30% of maximum load, our model suggests that loads of 70% are a more efficient method of stimulating growth,” said Terentjev, who is a Fellow of Queens' College. “Below that, the opening rate of titin kinase drops precipitously and precludes mechanosensitive signalling from taking place. Above that, rapid exhaustion prevents a good outcome, which our model has quantitatively predicted.”

“One of the challenges in preparing elite athletes is the common requirement for maximising adaptations while balancing associated trade-offs like energy costs,” said Fionn MacPartlin, Senior Strength & Conditioning Coach at the English Institute of Sport. “This work gives us more insight into the potential mechanisms of how muscles sense and respond to load, which can help us more specifically design interventions to meet these goals.”

̽��ֱ��model also addresses the problem of muscle atrophy, which occurs during long periods of bed rest or for astronauts in microgravity, showing both how long can a muscle afford to remain inactive before starting to deteriorate, and what the optimal recovery regime could be.

Eventually, the researchers hope to produce a user-friendly software-based application that could give individualised exercise regimes for specific goals. ̽��ֱ��researchers also hope to improve their model by extending their analysis with detailed data for both men and women, as many exercise studies are heavily biased towards male athletes.

Reference:
Neil Ibata and Eugene M. Terentjev. ‘Why exercise builds muscles: Titin mechanosensing controls skeletal muscle growth under load.’ Biophysical Journal (2021). DOI: 10.1016/j.bpj.2021.07.023

Researchers have developed a mathematical model that can predict the optimum exercise regime for building muscle.

Surprisingly, not very much is known about why or how exercise builds muscles: there’s a lot of anecdotal knowledge and acquired wisdom, but very little in the way of hard or proven data

Eugene Terentjev

John Arano on Unsplash

Woman lifting weights

Yes

Unhealthy patterns of diet, exercise, and sleep linked to high risk of cardiovascular disease in autistic people

cjb250 — Mon, 10 May 2021 15:34:45 +0000

̽��ֱ��results are published today in the journal Molecular Autism.

Earlier research suggests that autistic people die 16-35 years younger than expected, and that greater health problems may contribute to this risk. ̽��ֱ��present study is the first to consider the diet, exercise, and sleep patterns of autistic adults and how these patterns may relate to health outcomes.

̽��ֱ��team at the Autism Research Centre in Cambridge developed an anonymous, online survey about lifestyle choices and daily habits, personal medical history, and family medical history. ̽��ֱ��final study included 1,183 autistic adults and 1,203 non-autistic adults aged 16-90 years.

̽��ֱ��results showed that autistic adults were far less likely than non-autistic adults to meet very minimal health recommendations for diet, exercise, and sleep. Autistic adults were also far more likely to have atypical eating patterns (including limited diet) and sleep disturbance. They were more likely to be underweight or obese than non-autistic individuals.

These poor lifestyle habits were associated with greater risk of cardiovascular conditions such as high blood pressure, heart disease, and stroke among autistic males, and this was a stronger association even than a family history of a cardiovascular condition. Though it is not possible to say conclusively that a poorer lifestyle led to cardiovascular problems, the findings provide the first indication that promoting healthy choices regarding diet, exercise, and sleep may help to reduce the excess risks of health conditions in autistic adults.

While the results indicate that there may be other biological or environmental factors that leave autistic individuals at greater risk of health conditions, they also provide a clear target for intervention. Difficulties with maintaining a healthy lifestyle may also have knock-on effects beyond physical health, including limiting opportunities for social interaction (which may centre around mealtimes or exercise), and could contribute to worsening mental health, and affect employment or education.

̽��ֱ��lead researcher of the study, Elizabeth Weir, a PhD student at the Autism Research Centre in Cambridge, said: “These findings help us to better understand the experiences of autistic adults, and have wider implications for quality of life. We need to understand the reasons for restricted diet, limited exercise, and lack of sleep, to provide better support. This may include programmes for health education, and additional mental health support or supported living and working schemes.”

Dr Carrie Allison, Director of Research Strategy at the Autism Research Centre and a member of the research team, said: “ ̽��ֱ��challenges we see among autistic children regarding lifestyle behaviours extend into adulthood. Given the implications for risk of chronic disease and length of life, it is critical that we work to identify effective strategies for supporting health choices by autistic people of all ages.”

Professor Simon Baron-Cohen, Director of the Autism Research Centre and a member of the team, said: “ ̽��ֱ��wider picture suggests that autistic adults experience vulnerability in a variety of contexts, and this is just one new area that we should consider. Seeing that autistic adults are having such a hard time comparatively with healthy lifestyle habits has clear healthcare and policy implications: we need to create new and better support systems tailored to the specific needs of autistic people.”

Reference
Weir, E., et al. An investigation of the diet, exercise, sleep, BMI, and health outcomes of autistic adults. Molecular Autism 12, 31 (2021). DOI: 10.1186/s13229-021-00441-x

Funding
Funding for this project was generously provided by the Autism Research Trust, the Rosetrees Trust, and the Cambridge and Peterborough NHS Foundation Trust, the Corbin Charitable Trust, the MRC, the Wellcome Trust and the Innovative Medicines Initiative.

Autistic people have far greater risks of long term physical health conditions than others, but the reasons for this remain unclear. New research from the ̽��ֱ�� of Cambridge suggests that unhealthy lifestyle habits may be an important contributing factor.

These findings help us to better understand the experiences of autistic adults, and have wider implications for quality of life. We need to understand the reasons for restricted diet, limited exercise, and lack of sleep, to provide better support

Elizabeth Weir

Peter Burdon

Tiles spelling "autism"

Yes

Licence type:

Public Domain

Moderate exercise in middle and older age cuts time spent in hospital

ta385 — Thu, 07 May 2020 13:00:00 +0000

Inactive participants in the study spent just over four days more in hospital over the next ten years than those who did at least some physical activity, whether for work or leisure. And similar results were observed ten years later when the same participants were 50–90 years old.

̽��ֱ��study, by researchers at the ̽��ֱ�� of Cambridge’s Department of Public Health and Primary Care and MRC Epidemiology Unit, calculates that for every inactive person who started to take at least some exercise, the NHS could save around £247 per year. This would equate to around 7% of the UK’s per capita health expenditure.

̽��ֱ��findings, published in BMC Geriatrics, are based on a general British population cohort study of 25,639 men and women aged 40–79 living in Norfolk and recruited from general practices between 1993 and 1997 ( ̽��ֱ��European Prospective Investigation into Cancer in Norfolk).

̽��ֱ��researchers found that in the first ten years active participants were 25–27% less likely than inactive participants to have more than twenty hospital days or more than seven admissions per year with similar results over the subsequent ten years. They also reported that in 9,827 study participants with repeated measurements, those who remained physically active or increased their activity were 34% less likely to spend twenty days in hospital.

Lead author Robert Luben from the Institute of Public Health says:

“Our study provides some of the clearest evidence yet that small, feasible increases in usual physical activity substantially reduce the future hospital usage of middle-aged and older people, and would significantly ease pressure on the NHS.”

̽��ֱ��study is one of relatively few to examine the physical activity (both occupational and leisure-time) of middle-aged and older men and women – validated against heart rate monitoring with individual calibration – and their subsequent healthcare use. As well as studying a large cohort over a long follow-up period, the researchers used record linkage to hospital data and took a range of demographic and lifestyle factors into account.

When recruited, participants completed a lifestyle questionnaire where they were asked about their physical activity. Occupational activity was assessed using a four category question (“sedentary”, “standing”, “moderate physical work” and “heavy manual work”) with examples such as office worker, shop assistant, plumber and construction worker respectively.

Leisure activity in both summer and winter was assessed from the number of hours per week spent cycling, attending keep fit classes or aerobics and swimming or jogging. Estimated average hours of leisure activity was calculated as the mean of summer and winter activities. Based on a score (validated using heart rate monitoring with individual calibration) combining leisure and occupational elements, individuals were categorised as “inactive”, “moderately inactive”, “moderately active” and “active”.

̽��ֱ��study found that those with a physical activity score of at least “moderately inactive” had fewer hospital admissions and fewer days in hospital, than those who were “inactive”.

While previous studies have suggested that pre-admission physical activity programmes may lower duration of hospital stay, these are short term, require funding and are targeted at a limited number of individuals. But these new findings indicate that usual physical activity patterns in the general population predict hospital usage over the next two decades.

̽��ֱ��researchers acknowledge that participants may be physically inactive because of known or preclinical illness which may also predispose them to increased later hospitalisation. But sensitivity analyses excluding those with a self-reported chronic disease at baseline (heart attack, stroke or cancer), and excluding hospital admissions occurring in the first five years of follow-up, did not differ materially from the main findings.

Reference

R. Luben, S. Hayat, N. Wareham, P. Pharoah, K-T. Khaw, ‘Usual physical activity and subsequent hospital usage over 20 years in a general population: the EPIC-Norfolk cohort’. BMC Geriatrics, 6 May 2020). DOI: 10.1186/s12877-020-01573-0.10.1186/s12877-020-01573-0.

Men and women aged 40–79 are at significantly lower (25–27%) risk of long or frequent hospital admissions if they do some form of physical activity, a new study suggests.

Small, feasible increases in usual physical activity substantially reduce the future hospital usage of middle-aged and older people

Robert Luben

MabelAmber

A couple cycling

Yes