Dr Karl Gruber (PhD) reports on home-ground research kicking goals for heart health.
A love song can help with a broken heart, but major lifestyle changes are needed to fix an ailing one.
As we age, our body starts to do things we rather it didn’t – our hair turns grey (or falls out altogether), our joints ache, our skin wrinkles and our eyes and ears don’t work as well as they did.
It is all part of growing old, some say. But there is one affliction of ageing that should never be dismissed as normal: an ailing heart.
Heart-related problems are the number one cause of death worldwide, killing nearly nine million people in 2019. In Australia, heart-related problems caused 41,800 deaths in 2018, mostly due to coronary heart disease and stroke, the two most common forms of heart disease.
The good news is that, for most people, heart-related conditions are preventable. Changes in lifestyle such as improved diet and more exercise can have a positive impact on the functioning of the heart.
With these issues in mind, two Perth-based research teams are looking for the best way to improve heart health.
Researchers, led by Professor Daniel Green, Professor of Exercise and Sport Science at the University of Western Australia, were recently awarded a major grant from the National Health and Medical Research Council (NHMRC) to examine whether exercising at a young age could have lasting benefits in heart health.
A 2017 study in rats showed that juvenile rats exercising five times a day for four weeks had a 36% increase in the number of heart cells.
“This study showed that exercise resulted in a substantially larger number of heart cells (20 million more) and 15% larger heart size in later life,” Prof Green said.
Finding that exercise can lead to such large increase in heart cells is a big deal as the current dogma is that we have, from birth, a fixed number of heart cells.
“Although we knew that heart cells could increase in size with exercise training, the heart was previously considered incapable of growing new cells after birth,” Prof Green said. “If true in humans, it would have profound implications for lifelong heart function and health.”
If these results hold for humans, there are significant implications for public health policy.
According to Prof Green, this research raises important questions. For example, when is the best time to apply early health interventions for CV prevention? Or how is the health of your heart influenced by environmental factors during childhood or even in utero.
In this new project, Prof Green is taking advantage of the Raine Study’s significant dataset.
“The Raine Study possesses in utero and longitudinal developmental data of the gen1 offspring, with a high ongoing participation rate based on the incredible commitment and generosity of the participants,” Prof Green said. “It is richly characterised, including adiposity, fitness, nutrition, sedentary behaviour and other risk factors across the lifespan of the children, who are now approaching 30 years of age.”
Today, the Raine Study has amassed data from gen1, as well as from their children and grandchildren. Even the parents of gen1 have been studied. This massive and unique dataset is now fuelling Prof Green’s project over the next three years as well as other projects.
“Our project uses retrospective data and newly acquired data,” he said. “The retrospective cohort data will be used to determine what risk factor profiles in young people are related to (predict) the echo measures of adult heart structure and function that we will collect.”
More specifically, this new project will address questions such as how accurately foetal growth can predict the health of an adult’s heart and arteries; whether engaging in physical activity during childhood and/or adolescence results in improved heart and artery health; and at what stage of life is it best to intervene with exercise to optimise adult health outcomes.
While this project gets off the ground, Prof Green and his team have identified a simple way to improve the health of arteries without the need of drugs: exercise. In a study published last month, in the journal Hypertension, he reports that exercise can directly boost artery health.
In this study, the team addressed whether exercise alone was sufficient to improve artery health in middle-aged men. The study also evaluated whether low-dose testosterone supplementation provided significant benefits to artery health and function. Previous studies have suggested that testosterone supplementation may help improve health outcomes in middle-aged men, but not everyone is on board with this observation.
“Earlier studies showed that men who had higher testosterone levels and who were more physically active had better health outcomes. However, that could have been because those men were generally healthier at the outset,” said Professor Bu Beng Yeap, from the UWA Medical School, who co-authored the study.
“We needed to do a randomised controlled trial to find out whether giving men a combination of testosterone treatment and exercise training would improve artery health more than either alone, or neither,” he said.
The study recruited 80 men, aged between 50 and 70 years, with no history of heart disease and with low-to-medium levels of testosterone. The men were assigned to four groups, either i) receiving a testosterone supplement and exercising for 12 weeks, ii) doing exercise without the testosterone supplementation, iii) receiving only testosterone or iv) neither receiving testosterone nor exercising.
After analysing their data, the team found that only the participants who exercised had artery health benefits, with participants exercising without testosterone supplementation having the highest improvement: artery function improved by 28% in this group.
“Our key findings were that exercise training improved artery health, but testosterone treatment did not. We were surprised, as we had expected that men receiving both testosterone treatment and exercise training might have the largest improvement in artery health, but testosterone didn’t add anything to the benefit of exercise,” Prof Yeap said.
The findings of this study send a strong message to men aged 50-70 with a waist circumference of 95cm or more: they can improve the health of their arteries by doing regular exercise. The recommendations are in line with official guidelines from the Australian Department of Health (DoH), which warn that “for men, waist circumference of 94cm or more indicates an increased risk
of chronic disease.”
Beyond exercise, following a healthy diet is another key aspect affecting heart health, especially in people with early signs of heart disease.
Jonathan Hodgson, Professor of Nutrition and Epidemiology at the School of Medical and Health Sciences at Edith Cowan University, is a director of the WA Cardiovascular Research Alliance, which was set up in 2019 to unify heart, stroke and vascular disease researchers.
He is leading a study that aims to improve the diet and lifestyle of older Australians.
High intake of fruits and vegetables as well as regular exercise are well established ways to prevent cardiovascular disease. For adults, the DoH recommends a bit over five servings of vegetables a day (alongside other healthy foods). For exercise, official guidelines recommend 2.5 to five hours of moderate intensity physical activity a week or 1.5 to 2.5 hours of vigorous intensity physical activity. But the reality is that only a small number of Australians follow these guidelines.
“Increased fruit and vegetable intake and physical activity are regarded as cornerstones of lifestyle approaches for cardiovascular disease (CVD) primary prevention. However, only one in 20 Australian adults meet current fruit and veg recommendations, and over two-thirds are sedentary or have low levels of physical activity,” Prof Hodgson said.
In his new study, Prof Hodgson will test a new strategy to encourage people to improve their diet and lifestyle. The plan is to provide patients and their GPs with information about the health of their arteries, measured as levels of abdominal aortic calcification or AAC.
His goal is to provide people with a visual representation of their own level of AAC which is a marker of damage on their arteries and risk of future CVD events. With this knowledge, Prof Hodgson hopes people will make long-lasting positive changes in their diet and lifestyle.
“AAC is a safe, low cost and specific marker of structural CVD that can be identified routinely in almost any individual using widely available bone density machines. AAC strongly predicts CVD deaths and all-cause mortality, independent of CVD risk factors,” Prof Hodgson said.
“Our primary aim is to determine if providing an individual with knowledge of their AAC can lead to improved diet quality and levels of physical activity.”
Prof Hodgson’s study is underway and expected to be completed by mid-2022. Participants of this 12-week randomised controlled trial are randomly assigned to either receive information about their AAC levels at the start of the trial or at the end. Both groups receive standardised diet and lifestyle counselling via videos and after the 12 weeks participants will be evaluated to determine how well they followed exercise and dietary guidelines.
“This is the first study in a primary prevention setting designed to evaluate the impact of knowledge of a measure of advanced vascular disease on diet and lifestyle change,” Prof Hodgson said.
While the AAC test is not routinely available at this time, it is possible to capture a lateral spine image using bone density machines at the time of bone density testing, Prof Hodgson explains, and in the future, accessibility to this test might improve.
“If the value of providing the AAC test results to patients and their GPs is demonstrated, then it would be easy for GPs to order this test either at the time of the bone density test or independent of a bone density test,” Prof Hodgson said.
Currently, the research team is developing an automated software to help doctors with the identification and assessment of AAC, which currently must be done by experts, said AAC study co-lead Associate Professor Josh Lewis.
The take-home message here is that we need to increase our intake of fruits and vegetables, as well as increase our weekly exercise levels. That is, if we want to dodge the bullet of an early death from heart disease.