What’s the SRC about?
Physical activity can have health benefits for people with cystic fibrosis, we all know that. However, many questions need to be answered to ensure physical activity has the greatest effect it can. The aim of the SRC is to find some answers to a range of questions:
1. What is the optimum level of exercise people with CF should take part in? What intensity (how hard it is) and length of exercise is needed to give the most beneficial effects?
2. What are the physiological limitations of people with CF doing exercise, in comparison to healthy people? For example, what impact do reduced lung function, lung infections and CFTR gene mutations themselves have on their physical activity.
3. How can people with CF, their families, friends and clinical teams work out the best way to fit physical activity into their lives?
The research is being led by Dr Craig Williams and colleagues based in Exeter. Other parts of the study are being conducted in Swansea, Toronto in Canada and Australia respectively (such a geographical spread of collaborators means some very early starts for the Exeter team at their regular teleconferences!).
What are the limitations to measuring the benefits of exercise?
In order to work out what the best level of physical activity is for people with CF, there need to be effective and reliable ways to measure how much exercise people are doing. These can range from ways of literally measuring movement, for example the type of thing that is within a pedometer or accelerometer, to answering questionnaires about the amount of activity someone has completed, through to monitoring physical activity online. For all of these measurements, adjustments need to be made to take into account that someone has cystic fibrosis.
PhD student Mayara Silveira based in Dr Melitta McNarry’s research group in Swansea is currently working on calibrating the ‘accelerometer’ within pedometers. An accelerometer is the part that measures movement. Once an accelerometer has recorded how much someone moves, then maths equations are applied to convert the movement into how much energy has been used to make the movement. These equations were worked out using information from healthy people. People with CF may use energy differently to healthy people so these equations are unlikely to be accurate. Mayara had the unenviable task of reviewing 540,630 descriptions of methods for interpreting accelerometer data, to hone in on the best set of equations for measuring physical activity in people with cystic fibrosis.
What happens in your body when you exercise?
When you take part in exercise the muscles that you are using need a good supply of energy for the muscles to contract. After a contraction, each individual muscle cell needs to be able to recover quickly, in order to get ready to contract again to keep you moving.
There’s a lot going on in the body for this to happen effectively. Firstly, there needs to be a good circulation of oxygenated blood to the muscles. Oxygen is fed into the muscle’s batteries known as the mitochondria to generate the energy supply. In turn the cell’s fuel is used to allow the muscle to contract. The muscle needs to move back to its starting position, and be reloaded with fuel ready for the next time the muscles get the signal to contract.
Does CF cause changes to how muscle cells work?
There are very mixed views among researchers as to whether there are changes to the muscle tissue itself in people with cystic fibrosis. However, the faulty CFTR gene, reduced/poor lung function and the presence of infections could all affect how the muscles work. Researchers are currently looking to find out how all these things affect: how much oxygen is supplied to the muscle and how efficiently it is used, how the mitochondria use energy and how much rest the muscle cell needs before it is ready to contract again.
Studies are underway as part of the SRC to investigate this. Toronto-based PhD student Jessica Caterini is measuring the effect of exercise in people with CF using MRI. She uses a specially-adapted MRI machine which incorporates an exercise bike into the machine, so the MRI can record the muscle as soon as possible post-exercise. The data collected from the MRI can tell researchers how the muscles are using energy. Jessica is future-proofing her studies by investigating the effects of taking CFTR modulators on how muscle reacts to exercise in people with cystic fibrosis.
At September’s CF’s Got Talent! competition we heard from Dr Sarah Denford on her study investigating things that motivate or discourage young people with CF from doing exercise. As Dr Denford explained, rather than asking people about doing physical activity, she asked those taking part in her study to show her photographs of the things they liked doing or things that stopped them doing exercise. The recording of Sarah’s presentation and those of the other CF’s Got Talent! presenters are still available to watch again.
It is important to understand people’s attitudes to doing physical exercise, so that researchers and health care teams can develop a way of promoting physical activity that is going to work for as many people as possible.
How do you feel about exercise?
The next stage of Dr Denford’s research is to conduct a survey about people’s attitudes to doing physical exercise and what their experiences are. She’d like to hear the views of young people with CF, parents and family members of people with CF and from healthcare teams who support people with CF.
Dr Denford said: “The results will increase our understanding of current attitudes and behaviours surrounding physical activity, and some of the barriers that obstruct physical activity. The information we obtain will help us develop educational materials to support adolescents with cystic fibrosis to be active without limitations.”
If you’re interested in taking part, find out more about the survey and complete it here. More information about the survey, how your data will be used and the aims of the study is provided before you start to answer any questions.