Publications by authors named "Christopher D Askew"

Exercise-induced release of irisin may contribute to the beneficial effects of exercise on brain health. Previous studies in healthy adults have shown ~15 % increase in short-term post-exercise irisin concentrations. However, previous research investigating the exercise-induced release of irisin in older populations is scarce and findings are highly variable.

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Background: Markers of arterial stiffness including high Augmentation Index (AIx) are associated with cardiovascular events and all-cause mortality and are reduced with exercise training. In trained individuals, the AIx response to peak exercise (exercise delta AIx75 [Ex-AIx75]) may better help identify the effect of age and sex on arterial stiffening compared with conventional resting measures. This study aimed to determine the effect, and contribution of age, sex, peak oxygen (O2) uptake (V̇O2peak), mean weekly training load and lifetime training on resting AIx75, and Ex-AIx75 of healthy aerobic trained adults.

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Introduction: Development of clinical skills in areas, such as exercise risk stratification, testing, prescription, monitoring and outcome assessment, is vital for patient safety and clinical effectiveness in clinical exercise physiology (CEP). This study explored how current CEP courses are being taught and assessed and to identify potential best practice recommendations from a variety of stakeholders METHODS: Qualitative methods were employed to explore the thoughts of CEPs, academics and current students regarding the teaching and assessment of CEPs in the UK. Research design involved (1) semistructured interviews with students (n=16) and (2) focus groups with academics (n=8) and CEP (n=5) stakeholders.

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Peripheral arterial disease (PAD) is characterised by atherosclerotic stenosis or occlusion of arteries that leads to reduced blood flow to the limbs. PAD is associated with a very high rate of cardiovascular morbidity and mortality making the health and economic burden of PAD substantial. Despite high-quality evidence and international guidelines recommending conservative medical management of risk factors, and exercise and lifestyle interventions, surgical revascularisation (open or endovascular) remains the main treatment for PAD.

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Introduction: Patients with peripheral artery disease (PAD) can experience intermittent claudication, which limits walking capacity and the ability to undertake daily activities. While exercise therapy is an established way to improve walking capacity in people with PAD, it is not feasible in all patients. Neuromuscular electrical stimulation (NMES) provides a way to passively induce repeated muscle contractions and has been widely used as a therapy for chronic conditions that limit functional capacity.

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Article Synopsis
  • Peripheral artery disease (PAD) causes narrowed arteries in the legs, leading to leg pain during walking, which hampers daily activities; supervised exercise can help improve walking ability.
  • This study will compare a cardiovascular rehabilitation (CR) program involving supervised exercise and education with usual care in 66 patients who have recently undergone lower limb revascularisation for PAD.
  • The effectiveness of the CR program will be evaluated based on improvements in walking capacity and quality of life over a 6-week period.
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Background: Exercise rehabilitation programmes are important for long-term health and wellbeing among people with cardiac and pulmonary diseases. Despite this, many people struggle to maintain their physical activity once rehabilitation ends. This repeated measures study tracked changes in physical activity behaviour and motivation during and after completing a community-based exercise rehabilitation programme.

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Article Synopsis
  • * The manuscript details CEP-UK's four-year journey toward gaining formal recognition and implementing regulation for clinical exercise physiologists, including consultation for registration and accreditation procedures.
  • * It outlines major milestones, the creation of a university curriculum framework, and future goals for the profession, providing clarity on the training and registration processes for aspiring clinical exercise physiologists in the UK.
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Vascular diseases of the lower limb contribute substantially to the global burden of cardiovascular disease and comorbidities such as diabetes. Importantly, microvascular dysfunction can occur prior to, or alongside, macrovascular pathology, and both potentially contribute to patient symptoms and disease burden. Here, we describe a non-invasive approach using near-infrared spectroscopy (NIRS) during reactive hyperemia, which provides a standardized assessment of lower limb vascular (dys)function and a potential method to evaluate the efficacy of therapeutic interventions.

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A low carbohydrate, high fat (LCHF) diet in athletes increases fat oxidation but impairs sports performance, potentially due to impaired exercise economy. Dietary nitrate supplementation can improve exercise economy via an increase in nitric oxide production, which is initiated by the reduction of nitrate to nitrite within the oral cavity. This reaction is dependent on the presence of nitrate-reducing oral bacteria, which can potentially be altered by dietary changes, including a LCHF diet.

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Background: The COVID-19 pandemic led to changes in the delivery of exercise physiology services. The lived experience of those who continued to provide or receive exercise physiology services during the heightened public health restrictions of the inaugural year of the COVID-19 pandemic has received little attention to date. Acquiring this knowledge will be fundamental in addressing whether telehealth is a viable option for service delivery in exercise care, research, and policy.

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Introduction: Regular aerobic exercise is associated with improved cognitive function, implicating it as a strategy to reduce dementia risk. This is reinforced by the association between greater cardiorespiratory fitness and larger brain volume, superior cognitive performance and lower dementia risk. However, the optimal aerobic exercise dose, namely the intensity and mode of delivery, to improve brain health and lower dementia risk has received less attention.

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New Findings: What is the central question of this study? We sought to investigate whether peripheral and cerebrovascular function are impaired in early and late postmenopausal females compared with premenopausal females, while also accounting for nitric oxide and estradiol levels. What is the main finding and its importance? We observed no differences in peripheral vascular and cerebrovascular function between healthy and physically active premenopausal females and early and late postmenopausal females. Our findings contradict previous cross-sectional observations of vascular and cerebrovascular dysfunction across menopause.

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Background: The COVID-19 pandemic markedly changed how healthcare services are delivered and telehealth delivery has increased worldwide. Whether changes in healthcare delivery borne from the COVID-19 pandemic impact effectiveness is unknown. Therefore, we examined the effectiveness of exercise physiology services provided during the COVID-19 pandemic.

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Purpose: Leg muscle microvascular blood flow (perfusion) is impaired in response to maximal exercise in patients with peripheral artery disease (PAD); however, during submaximal exercise, microvascular perfusion is maintained due to a greater increase in microvascular blood volume compared with that seen in healthy adults. It is unclear whether this submaximal exercise response reflects a microvascular impairment, or whether it is a compensatory response for the limited conduit artery flow in PAD. Therefore, to clarify the role of conduit artery blood flow, we compared whole-limb blood flow and skeletal muscle microvascular perfusion responses with exercise in patients with PAD (n=9; 60±7 years) prior to, and following, lower-limb endovascular revascularization.

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Introduction: The COVID-19 pandemic has led to a shift in healthcare towards telehealth delivery, which presents challenges for exercise physiology services. We aimed to examine the impact of the COVID-19 pandemic on the reach, efficacy, adoption and implementation of telehealth delivery for exercise physiology services by comparing Australian practises before (prior to 25 January 2020) and during the COVID-19 pandemic (after 25 January 2020).

Methods: This retrospective audit included 80 accredited exercise physiology clinicians.

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Article Synopsis
  • The study compared vascular function in older adults with mild cognitive impairment (MCI) versus those without.
  • Results showed higher cerebrovascular pulsatility and lower blood pressure responsiveness in MCI participants, while systemic vascular stiffness was greater and flow-mediated dilation was lower compared to controls.
  • The findings suggest that changes in systemic vascular health could influence brain blood flow and cognitive function, highlighting potential targets for intervention in MCI.
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New Findings: What is the topic of this review? This review focuses on the physiological impact of abdominal aortic aneurysm (AAA) on cardiorespiratory fitness and the negative consequences of low fitness on clinical outcomes in AAA. We also discuss the efficacy of exercise training for improving cardiorespiratory fitness in AAA. What advances does it highlight? We demonstrate the negative impact of low fitness on disease progression and clinical outcomes in AAA.

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Physical activity (PA) participation was substantially reduced at the start of the COVID-19 pandemic. The purpose of this study was to assess the association between PA, mental health, and wellbeing during and following the easing of COVID-19 restrictions in the United Kingdom (UK) and New Zealand (NZ). In this study, 3363 adults completed online surveys within 2-6 weeks of initial COVID-19 restrictions (April/May 2020) and once restrictions to human movement had been eased.

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Community-based exercise programs for older adults play a potentially important role in mitigating the decline in functional outcomes, body composition, psychosocial outcomes, and cardiovascular health outcomes that commonly occurs with advancing age. There is a limited understanding of the characteristics and effectiveness of community-based exercise programs, particularly when those programs are offered outside metropolitan areas. Rural/regional settings face unique challenges, such as limited access to equipment/resources, transportation, and services, as well as significant costs to run programs.

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Article Synopsis
  • The UK is experiencing population growth and an increase in inactivity and health issues, highlighting the need for better exercise interventions to enhance health and reduce healthcare costs.
  • Current exercise strategies often rely on a 'one-size-fits-all' approach that doesn't provide significant health benefits, especially for those with chronic conditions.
  • The proposal recommends establishing a clinical exercise physiology profession in the UK, similar to successful models in Australia, with accredited professionals trained to offer personalized exercise prescriptions and support behavioral changes in physical activity.
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Background And Aim: Contrast-enhanced ultrasound (CEUS) measures of post-occlusion skeletal muscle microvascular responsiveness demonstrate the microvascular dysfunction associated with ageing and age-related disease. However, the accessibility of CEUS is limited by the need for intravenous administration of ultrasound contrast agents and sophisticated imaging analysis. Alternative methods are required for the broader assessment of microvascular dysfunction in research and clinical settings.

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The endothelium is the single-cell monolayer that lines the entire vasculature. The endothelium has a barrier function to separate blood from organs and tissues but also has an increasingly appreciated role in anti-coagulation, vascular senescence, endocrine secretion, suppression of inflammation and beyond. In modern times, endothelial cells have been identified as the source of major endocrine and vaso-regulatory factors principally the dissolved lipophilic vosodilating gas, nitric oxide and the potent vascular constricting G protein receptor agonists, the peptide endothelin.

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Article Synopsis
  • The study compares high cardiorespiratory fitness (CRF) levels in endurance athletes to lower levels in sedentary adults, highlighting significant benefits on cerebrovascular outcomes like cerebrovascular resistance and reactivity as measured by various imaging techniques.
  • The systematic review included 20 studies, showing that higher CRF was associated with decreased cerebrovascular resistance and enhanced reactivity, with stronger effects observed in male-only studies compared to mixed or female studies.
  • Exercise training had little effect on middle cerebral artery velocity and only slight, nonsignificant improvement in cerebrovascular reactivity, suggesting that while high CRF is beneficial for cerebrovascular function, exercise interventions alone may not strongly influence global cerebral blood flow or MCAv.
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New Findings: What is the topic of this review? We have conducted a systematic review and meta-analysis on the current evidence for the effect of heat therapy on blood pressure and vascular function. What advances does it highlight? We found that heat therapy reduced mean arterial, systolic and diastolic blood pressure. We also observed that heat therapy improved vascular function, as assessed via brachial artery flow-mediated dilatation.

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