A Tailored Prescription in Exercise
As a PhD student, Daniel Green had a keen interest in finding new ways to help sporting people get better at what they do. However, it wasn’t long before he realised that many of the techniques he used to measure human fitness and function could be applied to people at the other end of the health spectrum; patients with heart disease and end-stage heart failure. In subsequent years, Prof Green developed a team at UWA that has had profound impacts on establishing exercise science a recognised allied health profession, leading worldwide agendas to optimise the way that patients are clinically managed using exercise and establishing a better understanding of how exercise exerts its benefits on the heart and arteries.
In 1991, as a fresh graduate from UWA’s Exercise and Sport Science School, Daniel Green had a keen interest in finding new ways to help sporting people get better at what they do. However, it wasn’t long before he realised that many of the techniques he used to measure human fitness and function could also be applied to people at the other end of the health spectrum; patients with heart disease and end-stage heart failure. Thus began a 25 year journey which has seen Clinical Exercise Science established as an allied health profession, with Prof Green’s team leading international agendas in this field.
The research aimed to:
- understand how the heart and arteries work, particularly during exercise and after training;
- develop new methods for early detection of cardiovascular disease, before heart attack and stroke occur, so that prevention is possible; and
- develop personalised, targeted and evidence-based exercise interventions for patient benefit.
Cardiovascular disease and exercise
One in six Australians is affected by cardiovascular issues such as heart attacks, stroke, obesity and type 2 diabetes.
While decades of research has focused on the effects of exercise on risk factors such as blood pressure and lipids, studies conducted by Prof. Green and his team considered the direct impact of exercise on the arteries and heart. They found that artery function improved, even in people in whom “traditional” risk factors didn’t change, demonstrating the importance of exercise in maintaining good cardiovascular health.
In 1997, Dr Green set up the first research intensive Clinical Exercise Physiology service in an Australian hospital, while working with Professors Roger Taylor and Gerry O’Driscoll in the Cardiology and Heart Transplant Units at Royal Perth Hospital (RPH). By 2008, he established the CardioVascular Exercise Science group at UWA. This now includes a team of 18 researchers and graduate students. Adopting a hub-and-spoke approach, the group contributes to clinical exercise and research collaborations in all of the major teaching hospitals, including Fiona Stanley, RPH, Sir Charles Gairdner Hospital (SCGH), Princess Margaret Hospital (PMH) and the Perkins Institutes, with patients participating in the research.
A novel early detection tool
Prof. Green’s team has developed novel approaches to the non-invasive assessment of artery function and health in humans, using sophisticated imaging and software. These techniques assess high resolution images of the arteries inside the human body, providing early indications of the health and wellbeing of the cardiovascular system. The early detection systems that have been developed can indicate whether cells are functioning in a healthy way, which is often the first sign that future plaque will develop or that heart attacks may happen. Early detection allows for early prevention, and ultimately less heart attacks and stroke.
We developed one of the industry standard systems which has been adopted for use world-wide.
Prof Daniel Green
The technique and exercise interventions developed by this Western Australian research team have been incorporated into patient management guidelines and been adopted worldwide. Prof V Baltzopoulos from the UK Research Institute for Sport and Exercise Sciences has had the opportunity to work alongside Prof D Green and notes that “for the first time in humans, [Prof Green] has provided real time high resolution assessment of the size of, and blood flow through, human conduit arteries in vivo. The edge-detection and wall tracking software that he developed is now used worldwide by scientists who study human cardiovascular physiology and medicine”.
Improving outcomes for obese children with type 2 diabetes
By 2002, the team expanded their focus to include early prevention and children’s health.
We were seeing a lot of adults whose issues started when they were kids. We thought, wouldn’t it be good to prevent people turning up, rather than trying to fix someone late in the process?
Prof Daniel Green
Working with PMH, PhD students (including now Dr Louise Naylor who continues this work as a Senior Lecturer at UWA) conducted exercise studies, applying their techniques to obese children and those with type 2 diabetes; conditions highly related to inactivity. The team found that increased exercise and cardiovascular fitness improved artery function and insulin sensitivity; adaptations needed to keep blood glucose levels in the normal range and, ultimately, to prevent heart disease.Novel imaging techniques show the impact of exercise, of distinct types, on the way the heart is structured and how it functions
A succession of UWA PhD students embedded at PMH built research capacity around exercise science at the hospital, providing evidence to change the behaviour of children that will impact them into the future. The Endocrinology and Diabetes Department at PCH (former PMH) now offers the Healthy Weight Service for children and adolescents on referral.
Exercise Science as an allied health profession
Exercise was traditionally prescribed to induce changes in blood pressure and blood tests, like cholesterol levels. Prof. Green’s research found that whilst this was important, it was not the complete story. Instead, exercise has benefits that exceed those related to traditional risk factors, with direct mechanical effects of exercise on the inside of arteries that prevent heart attack and stroke. Physiologists could now fill the ‘risk factor gap’ by providing a full picture of the benefits of exercise on the heart and arteries of individuals.
The success of the Clinical Exercise Physiology service originally established by Prof Green at RPH led to a cardiac rehabilitation service for the RPH Cardiology Department and then across the Metropolitan Health Services of Western Australia. These services evolved into programs at major hospitals in Western Australia, employing numerous clinical exercise scientists and providing a scientific basis of the best way to rehabilitate people.
Exercise physiologists became heart transplant team unit members worldwide, in part because of what we’d done at RPH
Prof Daniel Green
Now a recognised allied health profession in Australia, Advanced Exercise Physiologists are accredited by a National governing association: Exercise and Sports Science Australia (ESSA). Prof Green helped to develop the ESSA standards in cardiovascular disease when the organisation was established and as it has evolved.
Prevention is better than cure
How individuals respond to exercise depends on a number of factors including genetics, environmental influences and the type of exercise prescribed.
- In developing a tailored exercise method, Prof Green’s team considered the merits of existing types of training:
- Aerobic exercises such as running, walking and swimming increase blood flow through the heart as well as the size of the heart and arteries.
- Resistance exercise includes weight training and increases muscle size, but the heart and their arteries don’t improve in the same way.
Dealing with each individual to work out what type of exercise is best for them makes the biggest impact on their health.
Prof Daniel Green
In the early 2000s, Prof Green and his PhD students, including Dr Andrew Maiorana, developed a novel circuit weight training program, which has now been adopted internationally for use in cardiovascular disease patients.
Circuit weight training limits exercise to small muscle groups, in a circuit format, making the training more tolerable, and with less initial demand placed on the heart. Their studies suggested that moderate intensity circuit training improved artery health, functional capacity, body composition, and strength in subjects with cardiovascular diseases and in healthy subjects.
The team’s research has established that exercise induces large benefits in the health of the heart and arteries that people are not always aware of, and that cardiovascular disease can be prevented with the right types of exercise. This new understanding has had a profound impact on the future health of individuals and communities world-wide.
Impact in Action
Our research has a really direct impact on people’s lives, even in people who are very unwell and have had a heart attack or had a problem with their heart and that prevents them from enjoying life.
The first patient, a 59-year-old man
One early patient sent to Dr Green’s rehab service at RPH had end-stage heart failure and was unable to exercise. Waiting on the transplant list and running out of options, the decision was made to give him a growth hormone and an exercise program in the hope of making him fitter so that when a transplant came along, it might help him recover quicker. One month later, the patient was tested, his results doubled! It was the first time this was seen and the report was published in 1997 in The Lancet, one of the world’s best known medical journals.
A trip to Italy
There was one man in his 60’s that had end-stage heart failure with a prognosis of months. All he wanted to do was visit his parents in Italy but his disease was severe and he couldn’t fly. We exercised him in the gym for many months and his status improved so much that he got listed for a transplant, visited his parents and survived for many years, with a really good quality of life.
- Testimonial – A/Prof Gerry O’Driscoll, Cardiologist and Medical Head of Advanced Heart Failure and Cardiac Transplant Services, RPH, 2003.
- Testimonial – Mr Robert Larbalestier FRACS – Head, Cardiopulmonary Transplant Unit, Royal Perth Hospital (RPH), 2000.
- 2013 Canadian Cardiovascular Society Heart Failure Management Guidelines; PMID 24480445.
- Exercise and Sports Science Australia (ESSA) Position Statement on exercise training and chronic heart failure, 2010; PMID 20227917.
- American College of Sports Medicine (ACSM) and American Diabetes Association (ADA) Joint Position Statement on exercise and type 2 diabetes, 2010; PMID 21084931.
- American Heart Association 2009 Scientific Statement: Exercise Training for Type 2 Diabetes Mellitus: Impact on Cardiovascular Risk; PMID 19506108.
- American Diabetes Association consensus statement, 2006: Physical Activity/Exercise and Type 2 Diabetes; PMID 16732040.
- American Heart Association Scientific Statement: Exercise and Heart Failure, 2003; PMID 12615804.
- Testimonial – Prof Vasilious (Bill) Baltzopoulos – RISES (Research Institute for Sport and Exercise Sciences) Letter Oct 2019.