Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common form of HF in older adults, and is increasing in prevalence as the population ages. Furthermore, HFpEF is increasing out of proportion to HF with reduced EF... more
Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common form of HF in older adults, and is increasing in prevalence as the population ages. Furthermore, HFpEF is increasing out of proportion to HF with reduced EF (HFrEF), and its prognosis is worsening while that of HFrEF is improving. Despite the importance of HFpEF, our understanding of its pathophysiology is incomplete, and optimal treatment remains largely undefined. A cardinal feature of HFpEF is reduced exercise tolerance, which correlates with symptoms as well as reduced quality of life. The traditional concepts of exercise limitations have focused on central dysfunction related to poor cardiac pump function. However, the mechanisms are not exclusive to the heart and lungs, and the understanding of the pathophysiology of this disease has evolved. Substantial attention has focused on defining the central versus peripheral mechanisms underlying the reduced functional capacity and exercise tolerance among ...
Research Interests: Computed Tomography, Adolescent, Electrocardiography, Echocardiography, Congenital Heart Defects, and 23 morePregnancy, Case Report, Humans, Child, Female, Male, Clinical Sciences, Newborn Infant, Aged, Cardiac Catheterization, Middle Aged, Autopsy, Adult, Case reports, Myocardium, Public health systems and services research, Fetus, X ray Computed Tomography, Exercise Test, Heart Ventricles, Chest Pain, Angiology, and Patent Foramen Ovale
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The effect that supervised or unsupervised exercise training has on aerobic capacity (peak oxygen consumption [VO2peak]), muscle strength and quality of life in older women with heart failure remains unknown. To examine the effect of six... more
The effect that supervised or unsupervised exercise training has on aerobic capacity (peak oxygen consumption [VO2peak]), muscle strength and quality of life in older women with heart failure remains unknown. To examine the effect of six months (three months supervised followed by three months unsupervised) of aerobic training (AT) or combined aerobic and strength training (CAST) on VO2peak, muscle strength and quality of life in older women with heart failure. Twenty older women (mean age +/- SD, 72+/-8 years) with clinically stable heart failure were randomly assigned to AT (n=10) or CAST (n=10). Supervised AT was performed two days per week at 60% to 70% heart rate reserve, whereas unsupervised training was performed two days per week at a rate of perceived exertion of 12 to 14 on the Borg scale. The CAST group also performed one to two sets of low-to-moderate intensity strength training two days per week. Supervised AT or CAST resulted in an increase in VO2peak (12%; P<0.05) ...
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Short or long-term athletic training has been associated with left ventricular (LV) morphological adaptations, including increases in wall thickness, cavity dimension and estimated LV mass. A limitation of previous studies assessing the... more
Short or long-term athletic training has been associated with left ventricular (LV) morphological adaptations, including increases in wall thickness, cavity dimension and estimated LV mass. A limitation of previous studies assessing the 'athlete heart' was that exercise training was performed at sea level. Since the 1968 Olympic summer games a popular method of maximizing athletic performance has been to use altitude training (AT) as a means of improving sea level performance. However, the effects of short term AT and taper training on LV morphology have not been well studied. Based on this limitation, the effects of three weeks of intense AT (1848 m) or low level control training (CT) (1050 m) followed by two weeks of taper training were investigated in 15 elite swimmers between 16 and 21 years of age. Short term AT or CT training followed by two weeks of taper training was not associated with alterations in LV diastolic cavity dimension (AT pre 53.3 +/- 2.8 mm versus post ...
Research Interests: Adolescent, Swimming, Echocardiography, Humans, Female, and 7 moreMale, Heart rate, Exercise, Follow-up studies, Adult, Altitude, and Heart Ventricles
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ABSTRACT The leading cause of death in developed countries is cancer, influenced by negative lifestyle factors including obesity, unhealthy diet, physical inactivity and addictive habits such as smoking and alcohol. These established... more
ABSTRACT The leading cause of death in developed countries is cancer, influenced by negative lifestyle factors including obesity, unhealthy diet, physical inactivity and addictive habits such as smoking and alcohol. These established cancer-promoting behaviors are also well-known causative factors of cardiac disease and cardiometabolic syndrome. While improved treatments have led to improved cancer-specific outcomes, many cancer survivors are now at increased risk of death from cardiovascular disease, as a result of pre-existing cardiometabolic syndrome and cardiometabolic toxicities of anti-cancer therapies. In the cardiology discipline, exercise therapy has a proven role in disease rehabilitation and risk reduction. The purpose of this review is to discuss the potential role of exercise interventions in risk reduction of cardiometabolic disease in adult cancer survivors.
This mini-review summarizes the literature regarding the mechanisms of exercise intolerance in patients with heart failure and reduced or preserved ejection fraction (HFREF and HFPEF, respectively). Evidence to date suggests that the... more
This mini-review summarizes the literature regarding the mechanisms of exercise intolerance in patients with heart failure and reduced or preserved ejection fraction (HFREF and HFPEF, respectively). Evidence to date suggests that the reduced peak pulmonary oxygen uptake (pulm VO2) in patients with HFREF compared to healthy controls is due both to central (reduced convective O2 transport) and peripheral factors (impaired skeletal muscle blood flow, decreased diffusive O2 transport coupled with abnormal skeletal morphology and metabolism). Although central and peripheral impairments also limit peak pulm VO2 in HFPEF patients compared to healthy controls, emerging data suggests that the latter may play a relatively greater role in limiting exercise performance in these patients. Unlike HFREF, currently there is limited evidence based therapies that improve exercise capacity in HFPEF patients, therefore future studies are required to determine whether interventions targeted to improve p...
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Research Interests: Running, Humans, Male, Heart rate, Boston, and 3 moreMiddle Aged, Time Factors, and Heart Transplantation
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Heart failure with preserved ejection fraction (HFpEF) is the most common form of heart failure (HF) in older adults. The primary chronic symptom in patients with HFpEF, even when well compensated, is severe exercise intolerance. Cardiac... more
Heart failure with preserved ejection fraction (HFpEF) is the most common form of heart failure (HF) in older adults. The primary chronic symptom in patients with HFpEF, even when well compensated, is severe exercise intolerance. Cardiac and peripheral functions contribute equally to exercise intolerance in HFpEF, though the latter has been the focus of fewer studies. Of note, multiple studies with exercise training have shown that exercise intolerance can improve significantly in the absence of improvements in exercise cardiac output, indicating a role of peripheral, noncardiac adaptations. In addition, clinical drug trials performed to date in HFpEF, all of which have focused on influencing cardiovascular function, have not been positive on primary clinical outcomes and most have not improved exercise capacity. Mounting evidence indicates that sarcopenic obesity, characterized by the coexistence of excess fat mass and decreased muscle mass, could contribute to the pathophysiology of exercise intolerance in older HFpEF patients and may provide avenues for novel treatments.
To assess the effects of long term (mean +/- SD 10+/-5 years, range three to 25 years) resistance training on left ventricular (LV) dimensions and mass. The study participants were 21 elite male power-lifters (age 33.4+/-5.9 years) and 10... more
To assess the effects of long term (mean +/- SD 10+/-5 years, range three to 25 years) resistance training on left ventricular (LV) dimensions and mass. The study participants were 21 elite male power-lifters (age 33.4+/-5.9 years) and 10 sedentary male control subjects (age 30.9+/-4.2 years). Two-dimensionally guided transthoracic M-mode echocardiograms were obtained at rest to quantify LV diastolic cavity dimension, posterior wall thickness, ventricular septal wall thickness and LV mass. Long term resistance training was not associated with an alteration in LV diastolic cavity dimension (resistance trained 54. 4+/-4.3 mm versus control 51.8+/-5.6 mm), ventricular septal wall thickness (resistance trained 9.7+/-1.0 mm versus control 10.1+/-0.7 mm), posterior wall thickness (resistance trained 9.6+/-1.5 mm versus control 9.3+/-1.4 mm) or LV mass (resistance trained 200. 3+/-32.5 g versus control 186.5+/-39.6 g). In addition, no resistance-trained athlete was found to have an LV mean...
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The assessment of cardiac function, particularly cardiac output (Q) during heavy exercise is essential for the evaluation of cardiovascular factors that might limit oxygen transport. A series of invasive and noninvasive techniques has... more
The assessment of cardiac function, particularly cardiac output (Q) during heavy exercise is essential for the evaluation of cardiovascular factors that might limit oxygen transport. A series of invasive and noninvasive techniques has been developed for the assessment and monitoring of Q during resting and submaximal exercise conditions. However, very few techniques have been found to give accurate and reliable determinations of Q during vigorous to maximum exercise. For exercise physiologists and sport cardiologists, maximal exercise data are of primary importance. The &#39;gold standard&#39; measures of cardiac function are considered to be the direct Fick and dye-dilution methods. These have been widely shown to give accurate and reliable determinations of Q during resting and submaximal exercise conditions; however, their use during maximal exercise conditions is debatable due to the inherent risks involved with each and their increasing inaccuracy during the later stages of vigorous exercise. Thermodilution has also been considered to be a relatively good method for the determination of Q during rest and exercise conditions, but recent authors have questioned its use due to the nature of the measure and its inaccuracy during strenuous exercise. Various noninvasive measures of cardiac function have been developed to overcome the problems associated with the &#39;gold standard&#39; measures. The first part of this article discusses conventional techniques used in exercise physiology settings. The majority of these provide accurate and reliable determinations of Q during rest and submaximal exercise. However, very few techniques are suitable for maximal exercise conditions. Perhaps only the foreign gas rebreathe using acetylene (C2H2) meets all the criteria of being noninvasive, simple to use, reliable over repeated measurements, accurate and useful during maximal exercise.
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Objective: Heart failure with preserved ejection fraction (HFpEF) is a major cause of morbidity and mortality. Exercise training is an established adjuvant therapy in heart failure; however the effects of high-intensity interval training... more
Objective: Heart failure with preserved ejection fraction (HFpEF) is a major cause of morbidity and mortality. Exercise training is an established adjuvant therapy in heart failure; however the effects of high-intensity interval training (HIIT) in HFpEF are unknown. We compared the effects of HIIT versus moderate-intensity aerobic continuous training (MI-ACT) on peak oxygen uptake (VO2peak), left ventricular diastolic dysfunction, and endothelial function in patients with HFpEF. Materials and Methods: Nineteen patients with HFpEF (Age=70±8.3 years) were randomized to either HIIT (4 x 4 min at 85-90% peak heart rate, with 3 min active recovery) or MI-ACT (30 min at 70% peak heart rate). Fifteen patients completed exercise training (HIIT: n=9; MI-ACT: n=6). Patients trained 3 days/week for 4 weeks. Before and after training patients underwent a treadmill test for VO2peak determination, 2D-echocardiography for assessment of left ventricular diastolic dysfunction, and brachial artery fl...
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Develop an MRI method to estimate skeletal muscle oxygen consumption (VO2 ) with dynamic exercise using simultaneous measurement of venous blood flow (VBF) and venous oxygen saturation (SvO2 ). Real-time imaging of femoral VBF using a... more
Develop an MRI method to estimate skeletal muscle oxygen consumption (VO2 ) with dynamic exercise using simultaneous measurement of venous blood flow (VBF) and venous oxygen saturation (SvO2 ). Real-time imaging of femoral VBF using a complex-difference method was interleaved with imaging of venous hemoglobin oxygen saturation (SvO2 ) using magnetic susceptometry to estimate muscle VO2 (Fick principle). Nine healthy subjects performed repeated 5-watt knee-extension (quadriceps) exercise within the bore of a 1.5 Tesla MRI scanner, for test/re-test comparison. VBF, SvO2 , and derived VO2 were estimated at baseline and immediately (<1 s) postexercise and every 2.4 s for 4 min. Quadriceps muscle mass was 2.43 ± 0.31 kg. Mean baseline values were VBF = 0.13 ± 0.06 L/min/kg, SvO2 = 69.4 ± 10.1%, and VO2 = 6.8 ± 4.1 mL/min/kg. VBF, SvO2 , and VO2 values from peak exercise had good agreement between trials (VBF = 0.9 ± 0.1 versus 1.0 ± 0.1 L/min/kg, R(2) = 0.83, CV = 7.6%; SvO2 = 43.2 ± ...
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Heart transplant recipients are at an increased risk for cerebral hemorrhage and ischemic stroke; yet, the exact mechanism for this derangement remains unclear. We hypothesized that alterations in cerebrovascular regulation is principally... more
Heart transplant recipients are at an increased risk for cerebral hemorrhage and ischemic stroke; yet, the exact mechanism for this derangement remains unclear. We hypothesized that alterations in cerebrovascular regulation is principally involved. To test this hypothesis, we studied cerebral pressure-flow dynamics in 8 clinically stable male heart transplant recipients (62±8 years of age and 9±7 years post transplant, mean±SD), 9 male age-matched controls (63±8 years), and 10 male donor controls (27±5 years). To increase blood pressure variability and improve assessment of the pressure-flow dynamics, subjects performed squat-stand maneuvers at 0.05 and 0.10 Hz. Beat-to-beat blood pressure, middle cerebral artery velocity, and end-tidal carbon dioxide were continuously measured during 5 minutes of seated rest and throughout the squat-stand maneuvers. Cardiac baroreceptor sensitivity gain and cerebral pressure-flow responses were assessed with linear transfer function analysis. Heart...
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BACKGROUND: Currently, there are a lack of investigations that have examined the effect of participating in a comprehensive cardiac rehabilitation program on quality of life and physiological measures in women of different ages. The... more
BACKGROUND: Currently, there are a lack of investigations that have examined the effect of participating in a comprehensive cardiac rehabilitation program on quality of life and physiological measures in women of different ages. The purpose of this investigation was to examine the effect of participating in a comprehensive cardiac rehabilitation program on quality of life, exercise tolerance, blood pressure and lipids in women between 33 and 82 years of age. METHODS: The 126 women participated in a 14-week cardiac rehabilitation program that consisted of 7 weeks of formal supervised exercise training and 7 weeks of unsupervised exercise and lifestyle modification. Physiologic and quality of life outcome measures obtained at the outset and after 14 weeks included: 1) exercise treadmill time; 2) resting and peak systolic and diastolic blood pressure; 3) total cholesterol, low-density lipoprotein cholesterol, high density lipoprotein cholesterol and Triglycerides; 4) Cardiac Quality of...
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Recent advances in the pathophysiology of exercise intolerance in patients with heart failure with preserved ejection fraction (HFPEF) suggest that noncardiac peripheral factors contribute to the reduced peak V(o2) (peak exercise oxygen... more
Recent advances in the pathophysiology of exercise intolerance in patients with heart failure with preserved ejection fraction (HFPEF) suggest that noncardiac peripheral factors contribute to the reduced peak V(o2) (peak exercise oxygen uptake) and to its improvement after endurance exercise training. A greater understanding of the peripheral skeletal muscle vascular adaptations that occur with physical conditioning may allow for tailored exercise rehabilitation programs. The identification of specific mechanisms that improve whole body and peripheral skeletal muscle oxygen uptake could establish potential therapeutic targets for medical therapies and a means to follow therapeutic response.
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Female cardiac transplant recipients' aerobic capacity is 60% lower than sex and age-predicted values. The effect of exercise training on restoring the impaired aerobic endurance and muscle strength in female cardiac transplant... more
Female cardiac transplant recipients' aerobic capacity is 60% lower than sex and age-predicted values. The effect of exercise training on restoring the impaired aerobic endurance and muscle strength in female cardiac transplant recipients is not known. This study examined the effect that aerobic and strength training have on improving aerobic endurance and muscle strength in female cardiac transplant recipients. 20 female cardiac transplant recipients (51 +/- 11 years) participated in this investigation. The subjects performed a baseline six-minute walk test and a leg-press strength test when they were discharged following cardiac transplantation. The subjects then participated in a 12-week exercise program consisting of aerobic and lower extremity strength training. Baseline assessments were repeated following completion of the exercise intervention. At baseline, the cardiac transplant recipients' aerobic endurance was 50% lower than age-matched predicted values. The traini...
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Near infrared spectroscopy (NIRS) is used to assess muscle oxygenation (MO) within skeletal muscle at rest and during aerobic exercise. Previous investigations have used a single probe placement to measure MO during various forms of... more
Near infrared spectroscopy (NIRS) is used to assess muscle oxygenation (MO) within skeletal muscle at rest and during aerobic exercise. Previous investigations have used a single probe placement to measure MO during various forms of exercise. However, regional MO differences have been shown to exist within the same muscle which suggests that different areas of the same muscle may have divergent MO. Thus, the aim of this study was to examine whether regional differences in MO exist within the same muscle during different types of incremental (rest, 25, 50, 75, 100 % of maximum) exercise (1 leg knee extension (KE), 2 leg KE, or cycling). Nineteen healthy active males (Mean +/- SD: Age 27 +/- 4 yrs; VO2max: 55 +/- 11 mL/kg/min) performed incremental exercise to fatigue using each mode of exercise. NIRS probes were placed on the distal and proximal portion of right leg vastus lateralis (VL). Results were analyzed with a 3-way mixed model ANOVA (probe x intensity x mode). Differences in ...
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Contemporary pharmacologic therapies have greatly improved outcomes in patients with heart failure (HF). Exercise therapy also has become increasingly recognized and utilized over the last decade. Patients with HF undergo significant... more
Contemporary pharmacologic therapies have greatly improved outcomes in patients with heart failure (HF). Exercise therapy also has become increasingly recognized and utilized over the last decade. Patients with HF undergo significant central and peripheral deconditioning. Aerobic and resistance training in this patient population may improve quality of life, muscular strength, aerobic capacity, and potentially longevity. Those HF patients who are able to remain adherent to exercise training programs may improve their self-monitoring skills with respect to progressive volume overload, as well as their capacity for independent living, thereby reducing the likelihood of rehospitalization.
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Peripheral chemoreceptor activity/sensitivity is enhanced in chronic heart failure (HF) and sensitivity is linked to greater mortality. This study aimed to determine the role of the peripheral chemoreceptor in cardiovascular control at... more
Peripheral chemoreceptor activity/sensitivity is enhanced in chronic heart failure (HF) and sensitivity is linked to greater mortality. This study aimed to determine the role of the peripheral chemoreceptor in cardiovascular control at rest and during exercise in HF patients and controls. Clinically stable HF patients (n=11; EF: 39±5%) and risk-matched controls (n=10; EF: 65±2%) performed randomized trials with or without dopamine infusion (2µg/min/kg) at rest and during 40% maximal voluntary contraction handgrip (HG) exercise, and a resting trial of 2 minutes of inspired 100% oxygen. Both dopamine and hyperoxia were used to inhibit the peripheral chemoreceptor. At rest in HF patients, dopamine decreased ventilation (p=0.02), decreased total peripheral resistance index (TPRi; p=0.003), and increased cardiac and stroke indices (p≤0.01), yet there was no effect of dopamine on these variables in controls (p≥0.7). Hyperoxia lowered ventilation in HF (p=0.01), but not in controls (p=0.9)...
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Cardiac rehabilitation (CR) reduces mortality in women and men with coronary artery disease (CAD). The objective of this study was to examine sex differences in long-term mortality, based on CR referral rates and attendance patterns in a... more
Cardiac rehabilitation (CR) reduces mortality in women and men with coronary artery disease (CAD). The objective of this study was to examine sex differences in long-term mortality, based on CR referral rates and attendance patterns in a large CAD population. This is a retrospective cohort study. The Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) and Cardiac Wellness Institute of Calgary (CWIC) databases were used to obtain information on all patients. Rates of referral to and attendance at CR were compared by sex. Logistic regression models were constructed to assess whether sex predicted CR referral or completion. The association between referral, completion, and survival was assessed by sex using Cox proportional hazard models. 25,958 subjects (6374-24.6%-were women) with at least one vessel CAD were included. Females experienced reduced rates of CR referral (31.1% vs 42.2%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) and completion (50.1 vs 60.4%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). Adjusting for demographic and clinical characteristics, relative to men, CR referral was significantly lower in women (adjusted odds ratio (OR) 0.74, 95% CI 0.69, 0.79) as was CR completion (adjusted OR 0.73, 95% CI 0.66, 0.81). Women completing CR experienced the greatest reduction in mortality (HR 0.36, 95% CI 0.28, 0.45) with a relative benefit greater than men (HR 0.51, 95% CI 0.46, 0.56). This is the first large cohort study to demonstrate that referral to and attendance at CR is associated with a significant mortality reduction in women, comparatively better than that in men.
Patients with heart failure (HF) were once discouraged from participating in exercise programs because of concerns regarding safety and the potential for harm to an already damaged myocardium. However, studies over the last 3 decades have... more
Patients with heart failure (HF) were once discouraged from participating in exercise programs because of concerns regarding safety and the potential for harm to an already damaged myocardium. However, studies over the last 3 decades have provided extensive insights into both the health outcome benefits of exercise and the mechanisms underlying these benefits. Studies on the outcome benefits of exercise training, including mortality and hospitalization, have been convincing. This article reviews the physiologic benefits of exercise training in HF, studies on exercise training in women, results and implications of the HF-ACTION trial, and recent meta-analyses using the Cochrane data base.
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Renal transplant recipients (RTR) have reduced peak aerobic capacity, muscle strength, arterial function and an unfavorable cardiovascular disease risk (CVD) profile. This study compared the effects of 12 weeks of supervised endurance and... more
Renal transplant recipients (RTR) have reduced peak aerobic capacity, muscle strength, arterial function and an unfavorable cardiovascular disease risk (CVD) profile. This study compared the effects of 12 weeks of supervised endurance and strength training (EST, n = 16) versus usual care (UC, n = 15) on peak aerobic capicity, cardiovascular and skeletal muscle function, CVD risk profile, and quality of life (QOL) in RTR (55 ± 13 years). Peak aerobic capacity and exercise hemodynamics, arterial compliance, 24-h blood pressure, muscle strength, lean body mass, CVD risk score, and QOL were assessed before and after 12 weeks. The change in peak aerobic capacity (EST: 2.6 ± 3.1 vs. UC: -0.5 ± 2.5 mL/(kg·min)), cardiac output (EST: 1.7 ± 2.6 vs. UC: -0.01 ± 0.8 L/min), leg press (EST: 48.7 ± 34.1 vs. UC: -10.5 ± 37.7 kg) and leg extension strength (EST: 9.5 ± 10.3 vs. UC: 0.65 ± 5.5 kg) improved significantly after EST compared with UC. The overall change in QOL improved significantly after 12 weeks of EST compared with UC. No significant difference was found between groups for lean body mass, arterial compliance, 24-h blood pressure or CVD risk score. Supervised EST is an effective intervention to improve peak exercise aerobic capacity and cardiac output, muscle strength and QOL in clinically stable RTR.
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Combined strength and endurance training may result in alterations in left ventricular (LV) systolic function and morphology, however, the acute effect of high-intensity rowing exercise and concurrent training-induced adaptations on LV... more
Combined strength and endurance training may result in alterations in left ventricular (LV) systolic function and morphology, however, the acute effect of high-intensity rowing exercise and concurrent training-induced adaptations on LV systolic function are not well known. The purpose of this investigation was to assess LV systolic function before and after a simulated 2000-m rowing race on a Concept II rowing ergometer and evaluate these adaptations following 10 weeks of concurrent strength and endurance training. Furthermore, resting LV morphology was assessed prior to and following the 10-week training program. Ten male subjects underwent two-dimensional echocardiograms at rest, immediately following (95 +/- 27 s), as well as 5 and 45 minutes after, a simulated 2000-m rowing race. These measurements were also made before and after 10 weeks of training. Irrespective of testing time, performance of a 2000-m rowing race resulted in an increase in fractional area change (0.51 +/- 0.0...
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BACKGROUND: The effect of prolonged strenuous exercise (PSE) on left ventricular (LV) systolic function has not been well studied in younger female triathletes. This study examined LV systolic function prior to, during and immediately... more
BACKGROUND: The effect of prolonged strenuous exercise (PSE) on left ventricular (LV) systolic function has not been well studied in younger female triathletes. This study examined LV systolic function prior to, during and immediately following PSE (i.e., 40 km bicycle time trial followed by a 10 km run) in 13 younger (29 PlusMinus; 6 years) female triathletes. METHODS: Two-dimensional echocardiographic images were obtained prior to, at 30-minute intervals during and immediately following PSE. Heart rate, systolic blood pressure, end-diastolic and end-systolic cavity areas were measured at each time point. Echocardiographic and hemodynamic measures were also combined to obtain LV end-systolic wall stress and myocardial contractility (i.e., systolic blood pressure - end-systolic cavity area relation). RESULTS: Subjects exercised at an intensity equivalent to 90 PlusMinus; 3% of maximal heart rate. Heart rate, systolic blood pressure, systolic blood pressure - end-systolic cavity area...
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Cardiovascular disease is the leading cause of morbidity and mortality in kidney transplant recipients (KTR). Two risk factors for cardiovascular disease that have not been examined in this population are arterial compliance and aerobic... more
Cardiovascular disease is the leading cause of morbidity and mortality in kidney transplant recipients (KTR). Two risk factors for cardiovascular disease that have not been examined in this population are arterial compliance and aerobic capacity. The primary objective was to determine small and large artery compliance and aerobic endurance in KTR. A secondary objective was to explore the relationship between aging and arterial compliance and aerobic endurance in KTR. Sixty-two clinically stable KTR were recruited from the University of Alberta Renal Transplant Clinic. Small and large artery compliance was assessed using computerized arterial pulse waveform analysis. Aerobic endurance was determined using the six-minute walk test. Age-matched normative data from healthy individuals was used for comparison. Small arterial compliance was lower in KTR (5.5+/-3 ml/mm Hg x 100) compared to age-matched healthy individuals&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; predicted values (7.9+/-0.9 ml/mm Hg x 100, P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). No difference was found for large artery compliance between KTR (16.0+/-6.6 ml/mm Hg x 10) and age-matched healthy predicted values (15.2+/-1.3 ml/mm Hg x 10, P=0.5). Small and large artery compliance were 35% (P=0.026) and 36% (P=0.005) higher in younger (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;51 years) versus older (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;51 years) KTR, respectively. The six-minute walk distance was 28% lower in KTR (495+/-92 m) compared to healthy age-predicted values (692+/-56 m P&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001). Compromised arterial compliance and poor aerobic endurance may partially explain the high incidence of cardiovascular disease in KTR. Interventions demonstrated to improve these parameters may afford substantial clinical benefit in this population.
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Research Interests: Evidence Based Medicine, Treatment Outcome, Sensitivity Analysis, Exercise therapy, Humans, and 16 moreEffect size, Left Ventricular Assist Device, Meta Analysis, Subject headings, Systematic review, Clinical Sciences, Myocardial Infarction, Time Factors, Randomized Controlled Trial, Trials, Ventricular Remodeling, Ejection Fraction, Left Ventricular Function, Human Subjects, Web of Science, and Control Group
We developed a multivariate prediction equation for estimating the highest obtainable pulmonary oxygen uptake (VO2p) during the 6-minute walk test (6-MWT) in 54 organ transplant recipients: heart/heart-double-lung (n=14),... more
We developed a multivariate prediction equation for estimating the highest obtainable pulmonary oxygen uptake (VO2p) during the 6-minute walk test (6-MWT) in 54 organ transplant recipients: heart/heart-double-lung (n=14), kidney/kidney-pancreas (n=16), liver (n=14), double lung (n=8), bone marrow (n=2). They were of age, 48+/-12 years. Participants performed a 6-MWT during which expired gases were collected and analyzed with a portable metabolic system interfaced with a wireless heart rate monitor. The following variables significantly contributed to the model for predicting the highest obtainable 6-MWT VO2p: 6-MWT distance (m), age (years), gender (male=0, female=1), resting heart rate, peak heart rate, weight (kg), and transplant type (kidney/kidney-pancreas=1, other=0), where: VO2p=1.253+0.022 (6-MWT distance)+0.112 (age) -3.192 (gender) -0.104 (resting heart rate)+0.127 (peak 6-MWT heart rate)-0.084 (weight)+2.116 (transplant type). The explanatory variables in our final model accounted for 78% of the variance in 6-MWT VO2p. In conclusion, the addition of an easily estimated 6-MWT VO2p will provide added clinical information of functional capacity following an exercise rehabilitation intervention or during routine follow-up for organ transplant recipients.
Research Interests: Kidney transplantation, Probability, Transplantation, Humans, Walking, and 15 moreFunctional Capacity, Female, Organ Transplantation, Male, Heart rate, Oxygen Uptake, Liver Transplantation, Bone marrow, Prediction Model, Middle Aged, Bone Marrow Transplantation, Adult, Heart and Lung Transplantation, Oxygen Consumption, and Predictive value of tests
The effect of organ transplantation on arterial compliance, pulmonary oxygen uptake (VO2p) and heart rate kinetics during the 6-minute walk test (6-MWT) remains unknown. Twenty-two thoracic (heart and/or lung) organ transplant recipients... more
The effect of organ transplantation on arterial compliance, pulmonary oxygen uptake (VO2p) and heart rate kinetics during the 6-minute walk test (6-MWT) remains unknown. Twenty-two thoracic (heart and/or lung) organ transplant recipients (TOTR, 51+/-12 years) and 30 abdominal (kidney, kidney-pancreas, or liver) organ transplant recipients (AOTR, 46+/-11 years) from the 2006 Canadian Transplant Games, and 37 healthy controls (HC) completed a 6-MWT. VO2p, heart rate kinetics, and arterial compliance were determined. The 6-MWT distance and highest VO2p were significantly lower in TOTR and AOTR versus HC. The highest 6-MWT heart rate was lower in TOTR (11%) and AOTR (13%) versus HC. VO2p kinetics were slower in TOTR (52+/-11 sec, P&amp;amp;amp;amp;lt;or=0.001) and AOTR (45+/-24 sec, P&amp;amp;amp;amp;lt;or=0.001) versus HC (28+/-9 sec). Heart rate kinetics were slower in TOTR (100+/-49 sec) versus AOTR (41+/-21 sec, P&amp;amp;amp;amp;lt;or=0.001) and HC (34+/-21 sec, P&amp;amp;amp;amp;lt;or=0.001), but not between AOTR and HC. Small and large artery compliance were 26% (P=0.007) and 19% (P=0.004) lower, respectively, in TOTR versus HC. Large artery compliance was 14% lower in TOTR versus AOTR (P=0.017). 6-MWT distance was significantly related to VO2p kinetics (r=-0.35) and the highest 6-MWT VO2p (r=0.72). TOTR and AOTR have abnormal VO2p kinetics, which is secondary to prolonged heart rate kinetics and impaired vascular function in TOTR, but not AOTR.
Research Interests: Kinetics, Kidney transplantation, Transplantation, Humans, Walking, and 15 moreFemale, Organ Transplantation, Male, Heart rate, Oxygen Uptake, Liver Transplantation, Aged, Middle Aged, Adult, Heart Transplantation, Heart and Lung Transplantation, Pancreas Transplantation, Oxygen Consumption, Case Control Studies, and Physical Endurance
Research Interests: Breast Cancer, Risk assessment, Cardiovascular Risk, Postmenopausal Women, Humans, and 22 moreFemale, Heart, Body Mass Index, Impedance cardiography, Tamoxifen, Aged, Middle Aged, C reactive protein, Body Mass, Cardiac Output Monitoring, Risk Assessment, Lipid Profile, Pilot Projects, Cross Sectional Studies, Exercise Test, Oxygen Consumption, Exercise Tolerance, Cardiopulmonary Exercise Testing, Fasting Insulin, Oncologist, Case Control Studies, and Power Output
Molecularly targeted therapeutics (MTT) are the future of cancer systemic therapy. They have already moved from palliative therapy for advanced solid malignancies into the setting of curative-intent treatment for early-stage disease.... more
Molecularly targeted therapeutics (MTT) are the future of cancer systemic therapy. They have already moved from palliative therapy for advanced solid malignancies into the setting of curative-intent treatment for early-stage disease. Cardiotoxicity is a frequent and potentially serious adverse complication of some targeted therapies, leading to a broad range of potentially life-threatening complications, therapy discontinuation, and poor quality of life. Low-cost pleiotropic interventions are therefore urgently required to effectively prevent and/or treat MTT-induced cardiotoxicity. Aerobic exercise therapy has the unique capacity to modulate, without toxicity, multiple gene expression pathways in several organ systems, including a plethora of cardiac-specific molecular and cell-signaling pathways implicated in MTT-induced cardiac toxicity. In this review, we examine the molecular signaling of antiangiogenic and HER2-directed therapies that may underpin cardiac toxicity and the hypothesized molecular mechanisms underlying the cardioprotective properties of aerobic exercise. It is hoped that this knowledge can be used to maximize the benefits of small molecule inhibitors, while minimizing cardiac damage in patients with solid malignancies.
Research Interests:
Exercise training (ET) improves endurance capacity by increasing both skeletal muscle mitochondrial number and function, as well as contributing to favourable cardiac remodelling.Interestingly, some of the benefits of regular exercise can... more
Exercise training (ET) improves endurance capacity by increasing both skeletal muscle mitochondrial number and function, as well as contributing to favourable cardiac remodelling.Interestingly, some of the benefits of regular exercise can also be mimicked by the naturally occurring polyphenol, resveratrol (RESV). However, it is not known whether RESV enhances physiological adaptations to ET. To investigate this, male Wistar rats were randomly assigned to a control chow diet or a chow diet that contained RESV (4 g kg⁻¹ of diet) and subsequently subjected to a programme of progressive treadmill running for 12 weeks. ET-induced improvements in exercise performance were enhanced by 21% (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) by the addition of RESV to the diet. In soleus muscle, ET+RESV increased both the twitch (1.8-fold; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) and tetanic(1.2-fold; P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) forces generated during isometric contraction, compared to ET alone. In vivo echocardiography demonstrated that ET+RESV also increased the resting left ventricular ejection fraction by 10% (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05), and reduced left ventricular wall stress compared to ET alone.These functional changes were accompanied by increased cardiac fatty acid oxidation (1.2-fold;P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) and favourable changes in cardiac gene expression and signal transduction pathways that optimized the utilization of fatty acids in ET+RESV compared to ET alone. Overall, our findings provide evidence that the capacity for fatty acid oxidation is augmented by the addition of RESV to the diet during ET, and that this may contribute to the improved physical performance of rats following ET.