Keeron Stone

Cardiff Metropolitan University | cardiffmet · Cardiff School of Sport and Health Sciences

Background: Sedentary behaviour is associated with heightened cardiovascular disease (CVD) risk [1], with increased arterial stiffness (AS) being implicated as a principal pathophysiological mechanism. The current systematic review, with meta-analysis, aimed to consolidate and quantify the AS response to (1) prolonged uninterrupted sitting and (2)...

BACKGROUND The aortic-femoral arterial stiffness gradient, calculated as the ratio of lower-limb pulse-wave velocity (PWV) to central (aortic) PWV, is a promising tool for assessing cardiovascular disease (CVD) risk, but whether it predicts incident CVD is unknown. METHODS We examined the association of the aortic-femoral arterial stiffness gradie...

This study assessed the pooled effect of prolonged sitting (with and without interruption) on arterial stiffness (PWV). Uninterrupted sitting appears to significantly increase (worsen) arterial stiffness (cf-PWV), and interrupting sitting with bouts activity may confer some protective effect, but it does not remove it entirely.

Independently, both prolonged uninterrupted sitting and the onset of menopause negatively impact markers of cardiovascular risk. Whether their combination augment these responses additively remains unknown. This study assessed whether prolonged uninterrupted sitting causes greater central and peripheral cardiovascular dysfunction in post-menopausal...

Prolonged uninterrupted sitting of >3-hours has been shown to acutely cause central and peripheral cardiovascular dysfunction. However, individuals rarely sit uninterrupted for >2-hours, and the cardiovascular response to this time is currently unknown. In addition, whilst increased cardiorespiratory fitness (CRF) and habitual physical activity (HP...

Emerging evidence indicates that acute bouts of uninterrupted prolonged sitting decrease cerebral blood flow and impair executive function. Few studies have investigated the use of feasible sedentary behavior interruptions to attenuate these effects. This study aimed to investigate effects of intermittent half-squat exercises during prolonged sitti...

This review critiques the literature supporting clinical assessment and management of cardiovascular disease and cardiovascular disease risk stratification with brachial-ankle pulse wave velocity (baPWV). First, we outline what baPWV actually measures-arterial stiffness of both large central elastic arteries and medium-sized muscular peripheral art...

Overground robotic-assisted gait training (O-RAGT) has been shown to improve clinical functional outcomes in people living with stroke. The purpose of this study was to identify whether a home-based O-RAGT program, in combination with usual care physiotherapy, would demonstrate improvements in vascular health in individuals with chronic stroke, and...

Objective Pulse-wave velocity (PWV), a common measure of arterial stiffness, can be measured continuously and across multiple body sites using photoplethysmography (PPG). The objective was to determine whether a simple photoplethysmography PPG PWV method agrees with a referent device. Approach Photoplethysmography heart-finger PWV (hfPWV) and hear...

Exposure to acute prolonged sitting and consumption of a high fat (HF) meal have been shown to independently and additively impair central and peripheral cardiovascular function. This study sought to determine whether localized activity, namely leg fidgeting, offers a protective effect to these deleterious effects. Using a randomized crossover desi...

Sedentary behavior has been identified as an independent predictor of future cardiovascular disease risk and all-cause mortality. To explain this association, a growing body of literature has sought to investigate the physiological underpinnings of this association with the goal of developing a biologically plausible model. In time, this biological...

Low intensity active recovery such as walking appears to be optimal for the clearance of blood lactate (BLa) concentration following high intensity exercise. However, within a sporting context, competition rules or procedural impracticalities often mean walking is not possible. Leg fidgeting during sitting has been shown to increase leg blood flow,...

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 s...

Prolonged uninterrupted sitting and a typical Western meal, high in fat and refined sugar, can additively impair cognitive and cerebrovascular functions. However, it is unknown whether interrupting these behaviours, with a simple desk-based activity, can attenuate the impairment. The aim of this study was to determine whether regular leg fidgeting...

Background Previous reviews have shown that exposure to acute prolonged sitting can have detrimental effects on several cardiovascular and cardiometabolic health markers. However, to date, there has been no synthesis of peripheral blood pressure data (including systolic blood pressure, diastolic blood pressure and mean arterial pressure), an import...

Background & aims Atherosclerosis and arteriosclerosis contribute to vascular aging and cardiovascular disease (CVD) risk. Both processes can be assessed simply in the lower-limbs and reflect systemic pathology. However, only atherosclerosis is routinely assessed, typically via ankle-brachial index (ABI). Arteriosclerosis can be assessed using femo...

The aortic-femoral arterial stiffness gradient, defined as the ratio of femoral-ankle pulse wave velocity to carotid-femoral pulse-wave velocity, demonstrates good between-day reliability in young healthy adults.

Sedentary behavior, particularly sitting, is ubiquitous in many contemporary societies. This is a major societal concern considering the evidence for a strong association between sitting behavior and cardiovascular disease morbidity and mortality. Unsurprisingly, leading public health agencies have begun to advocate “reduction” in sitting behavior....

Independently, prolonged uninterrupted sitting and the consumption of a meal high in saturated fats acutely disrupt normal cardiovascular function. Currently, the acute effects of these behaviors performed in combination on arterial stiffness, a marker of cardiovascular health, are unknown. This study sought to determine the effect of consuming a h...

Background: Aortic arterial stiffness is a strong independent predictor of cardiovascular disease (CVD); however, its dependence on mean arterial pressure (MAP) limits its clinical utility. The aortic-femoral arterial stiffness gradient (af-SG), a novel marker of CVD risk, may be a promising alternative, but its dependence on MAP is not known. The...

Regular exposure to uninterrupted prolonged sitting and the consumption of high glycemic meals (HGI) is independently associated with increased cardiovascular disease risk. Sitting for as little as 1-hour can impair the health of both peripheral and central arteries. However, it is currently unknown whether combined acute exposure to uninterrupted...

Acute prolonged sitting leads to cerebrovascular disruptions. However, it is unclear how prolonged sitting interacts with other common behaviors, including high‐ (HGI) and low‐glycemic index (LGI) meals. Using a double‐blind randomized cross‐over design, this study evaluated the effects of prolonged (3 hr) sitting, with a high‐ (HGI; GI: 100) or lo...

Background: The aortic to femoral arterial stiffness gradient (af-SG) may be a novel measure of arterial health and cardiovascular disease (CVD) risk, but its association with CVD risk factors and CVD status, and whether or not they differ from the referent measure, carotid-femoral pulse-wave velocity (cfPWV), is not known. Method: Accordingly,...

Background: Carotid-femoral pulse-wave velocity (cfPWV) is the reference standard measure of central arterial stiffness. However, it requires assessment of the carotid artery, which is technically challenging, and subject-level factors, including carotid artery plaque, may confound measurements. A promising alternative that overcomes these limitati...

Objectives To assess the effect of a home-based over-ground robotic-assisted gait training program using the AlterG Bionic Leg orthosis on clinical functional outcomes in people with chronic stroke. Design Randomized controlled trial. Setting Home. Participants Thirty-four ambulatory chronic stroke patients who recieve usual physiotherapy. Inte...

Objectives: To assess physical activity (PA), mental health and well-being of adults in the UK, Ireland, New Zealand and Australia during the initial stages of National governments’ Coronavirus disease (COVID-19) containment responses. Design: Observational, cross-sectional Methods: An online survey was disseminated to adults (n = 8,425; 44.5 ± 1...

Background Exposure to acute prolonged sitting can result in vascular dysfunction, particularly within the legs. This vascular dysfunction, assessed using flow-mediated dilation (FMD), is likely the consequence of decreased blood flow-induced shear stress. With mixed success, several sitting interruption strategies have been trialled to preserve va...

Anthocyanin-rich New Zealand blackcurrant (NZBC) may improve forearm muscle oxygenation and enhance performance in high-level rock climbers. As such, using a double-blind, randomised, cross-over design study, twelve participants performed an oxidative capacity assessment, and two successive exhaustive exercise trials (submaximal forearm muscle cont...

Objectives: To assess how the early stages of National governments Coronavirus disease (COVID-19) containment strategies impacted upon the physical activity, mental health and well-being of adults in the UK, Ireland, New Zealand and Australia Design: Observational, cross-sectional Setting: Online survey disseminated in the UK, Ireland, New Zealand...

Flow-mediated slowing (FMS), defined as the minimum pulse wave velocity (PWV min ) during reactive hyperemia, is potentially a simple, user-objective test for examining endothelial function. The purpose of the current study was to determine the effects of a known endothelial dysfunction protocol on arm PWV and PWV min . Complete data were successfu...

Background: Carotid-femoral pulse wave velocity (cfPWV) is widely used in epidemiological studies to assess central arterial stiffness. However, despite being superior to traditional risk factors in predicting cardiovascular outcomes, cfPWV is not routinely used in clinical practice. cfPWV assessments require applanation of the carotid artery, whi...

Introduction: Carotid-femoral pulse wave velocity (cfPWV) is widely used in clinical and epidemiological studies to assess central arterial stiffness and predict cardiovascular outcomes. However, cfPWV assessments require applanation of the carotid artery, which may be challenging in some patients, and assessments may be confounded in the presence...

There has been a great deal of interest into the effects of prolonged sitting on lower limb vascular function. However, most studies use flow mediated dilation which is technically challenging. A simpler technique is pulse wave velocity (PWV) which can be estimated at any single arterial site of interest using a number of different calculations [Br...

Objectives: Idiopathic intracranial hypertension (IIH) is strongly related to obesity. The relationship between intracranial pressure, body mass index (BMI), percentage body fat and distribution of body fat in non-IIH patients remains less clear. The aim of this study was to examine the relationship between intracranial pressure and body type in n...

Pulse wave analysis (PWA) utilizes arm blood pressure (BP) waveforms to estimate aortic waveforms. The accuracy of central BP waveform estimation may be influenced by assessment site local haemodynamics. This study investigated whether local haemodynamic changes, induced via arm tilting ±30° relative to heart level, affect estimated central systoli...

New findings: What is the central question of this study? There is growing interest on the effects of sedentarism on central and peripheral cardiovascular health. To permit further investigation, including in larger epidemiological studies, there is a need to identify arterial health assessment tools that are valid (accurate) and reliable (precise...

Assessment of the SphygmoCor XCEL device's between-day reliability for measures of pulse wave velocity (PWV).

Intermittent exposure to hypoxia can lead to improved endurance performance. Currently, it is unclear whether peripheral adaptions play a role in improving oxygen delivery and utilization following both training and detraining. This study aimed to characterize skeletal muscle blood flow (mBF), oxygen consumption (mV̇O2), and perfusion adaptations t...

Objective: To determine which ultrasound-based, single-point arterial stiffness estimate is least dependent on blood pressure (BP) to improve assessment of local vascular function. Methods: Ultrasound was used to assess blood flow and diameters at the left brachial artery of 20 healthy adults [55% female, 27.9 years (5.2), 24.2 (2.8) kg/m]. BP o...

Prolonged, uninterrupted sitting negatively impacts markers of peripheral vascular health, particularly, vasodilatory function of leg arteries. Whether sitting can similarly impact measures of central vascular health, as well as overall leg vasoreactivity (i.e., vasodilatory and vasoconstrictor function) remains unknown. To address this, measuremen...

New findings: What is the central question of this study? Common carotid artery (CCA) two-dimensional strain imaging detects intrinsic arterial wall properties beyond conventional measures of arterial stiffness, but the effect of cardiorespiratory fitness on two-dimensional strain-derived indices of CCA stiffness is unknown. What is the main findi...

Central hemodynamic parameters, such as aortic systolic pressure (cSBP), augmentation index (AIx), and pressure wave forms (Pb) may offer clinicians superior prognostic information to peripheral systolic pressure (SBP). It is unknown whether changes in peripheral hemodynamics affect central hemodynamic measurements. The purpose of this study was to...

Stroke is a major global health problem whereby many survivors have unmet needs concerning mobility during recovery. As such, the use of robotic assisted devices (i.e., a bionic leg) within a community-setting may be an important adjunct to normal physiotherapy in chronic stroke survivors. This study will be a dual-centre, randomized, parallel grou...

Cardiovascular autonomic nervous system function can be assessed using an orthostatic challenge to induce arterial wave reflection. While arterial reflection is typically estimated using a central augmentation index, a superior estimation can be obtained using pulse wave separation analysis to estimate the aortic backward pressure wave (Pb). Howeve...

Background and aims: Although it is well known that resistance training (RT) is beneficial for patients suffering from a variety of cardiovascular diseases, it remains underutilized as a rehabilitation tool as there is no reliable way to monitor the additional stress placed on the central organs. The current study aimed to determine between-day re...

This study examined differences in the oxygenation kinetics and strength and endurance characteristics of boulderers and lead sport climbers. Using near infrared spectroscopy, 13-boulderers, 10-lead climbers, and 10-controls completed assessments of oxidative capacity index and muscle oxygen consumption (mV˙O2) in the flexor digitorum profundus (FD...

Following institutional ethical approval, 9 healthy males who were not forearm trained (mean age: 20.7 ± 1.1 years; stature: 1.77 ± 0.08 m; body mass: 84.0 ± 14.2 kg) volunteered to take part in the study. In a randomized, crossover design participants completed four weeks of progressive HGD endurance training (0.3Hz in week one increasing to 1.2Hz...

Purpose: To improve the current understanding of the impact of resistance exercise on the heart, by examining the acute responses of left ventricular (LV) strain, twist and untwisting rate ('LV mechanics'). Methods: LV echocardiographic images were recorded in systole and diastole before, during and immediately after (7-12 s) double leg press ex...

In patients with stroke or transient ischemic attacks (TIA), a decline in executive function may limit an individual's ability to process motor tasks and relearn motor skills. The purpose of this study was to assess the acute effect of exercise posture (seated vs. supine cycle ergometry) on executive function and prefrontal cortex perfusion in pati...

Presented at the BASES 2016 conference.

Altitude camps are popular amongst elite endurance athletes seeking performance enhancement. Such protocols are not feasible for many competitors due to financial, geographical and time-based limitations. Subsequently, live-low-train-high protocols are sometimes undertaken haphazardly in attempts to reap similar adaptations. The effects of such hyp...

Arterial wall mechanics likely play an integral role in arterial responses to acute physiological stress. Therefore, this study aimed to determine the impact of low and moderate intensity double-leg press exercise on common carotid artery (CCA) wall mechanics using 2D vascular strain imaging. Short-axis CCA ultrasound images were collected in 15 he...

Summary – Twenty-eight participants were divided into three groups: control (n=10), sport climbers (n=9) and boulderers (n=9) to investigate the determinants of grip strength between climbing disciplines. Forearm volume (FAV) was measured using water displacement method. Maximal volitional contraction (MVC) was assessed using an open crimp grip on...

Rock-climbing performance is largely dependent on the endurance of the forearm flexors. Recently, it was reported that forearm flexor endurance in elite climbers is independent of the ability to regulate conduit artery (brachial) blood flow, suggesting that endurance is not primarily dependent on the ability of the brachial artery to deliver oxygen...

Purpose: To induce lower limb blood volume shifts using a 10 min 70° head-up tilt, and: (1) in the soleus, determine the validity of an inexpensive continuous wave (cw)-NIRS device by comparing to a criterion frequency-domain (fd-) NIRS device, (2) determine the between-day reliability of soleus assessments obtained from cw-NIRS and fd-NIRS; and,...

Purpose: This study examined differences in oxygenation kinetics in the non-dominant and dominant flexor digitorum profundus (FDP) of rock climbers. Methods: Participants consisted of 28 sport climbers with a range of on-sight abilities (6a+ to 8a French Sport). Using near infrared spectroscopy, oxygenation kinetics of the FDP was assessed by ca...

Competitive rock climbing places a large physiological stress on the forearm flexors for prolonged periods of time. It has been suggested that higher-level rock climbers have a greater skeletal muscle oxidative capacity in their dominant forearm (flexor digitorum profundus [FDP]) when compared to their lower-level counterparts (Fryer et al., 2015,...

During an orthostatic challenge blood pooling in the small vessels of the legs reduces central venous return. This phenomenon can be assessed by measuring total haemoglobin (tHb) using near infra-red spectroscopy (NIRS). If valid and reliable, assessments of blood volume accumulation during an orthostatic challenge would be a useful test of integra...