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Impaired primary hemostasis and dysregulated angiogenesis, known as a two-hit hypothesis, are associated with gastrointestinal (GI) bleeding in patients with continuous-flow left ventricular assist devices (CF-LVADs). Exercise is known to influence hemostasis and angiogenesis in healthy individuals; however, little is known about the effect in patients with CF-LVADs. The objective of this prospective observational study was to determine whether acute exercise modulates two-hit hypothesis mediators associated with GI bleeding in patients with a CF-LVAD. Twenty-two patients with CF-LVADs performed acute exercise either on a cycle ergometer for approximately 10 minutes or on a treadmill for 30 minutes. Blood samples were taken pre- and post-exercise to analyze hemostatic and angiogenic biomarkers. Acute exercise resulted in an increased platelet count (p < 0.00001) and platelet function (induced by adenosine diphosphate, p = 0.0087; TRAP-6, p = 0.0005; ristocetin, p = 0.0009). Additionally, high-molecular-weight vWF multimers (p < 0.00001), vWF collagen-binding activity (p = 0.0012), factor VIII (p = 0.034), angiopoietin-1 (p = 0.0026), and vascular endothelial growth factor (p = 0.0041) all increased after acute exercise. This pilot work demonstrates that acute exercise modulated two-hit hypothesis mediators associated with GI bleeding in patients with CF-LVADs.
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Impaired endothelial function in people with coronary heart disease (CHD) is associated with increased mortality. Water immersion can increase peripheral artery shear stress which may provide an additional stimulus to the endothelium during exercise. This study compared the effects of water-based circuit exercise training (WEX) and gym-based circuit exercise training (GEX) on vascular function in people with stable CHD. Participants were randomized to 12 wk of WEX (n = 20), GEX (n = 20), or a control group (usual activities; n = 12). Endothelium-dependent flow-mediated dilation (FMD) and glyceryl trinitrate-mediated dilation (GTN) of the brachial artery were assessed pre- and postintervention. FMD increased following WEX [4.0% (3.0%-5.1%) to 5.3% (4.1%-6.5%); P = 0.016], but was unchanged following GEX [4.9% (3.8%-5.9%) to 5.0% (3.8%-6.1%); P = 0.822]. There were no between-group differences in the change in FMD and no significant changes in GTN-mediated dilation percentage. Triglycerides decreased following GEX [1.2 mmol·L-1 (1.0-1.4 mmol·L-1) to 1.0 mmol·L-1 (0.8-1.3 mmol·L-1); P = 0.022], but there were no further differences in lipid profiles. WEX improved endothelial function of the brachial artery in people with stable CHD, suggesting that WEX is an effective alternative to gym-based exercise in people living with CHD, which may specifically address vascular health.NEW & NOTEWORTHY This study found that 12 wk of water-based circuit exercise training was well tolerated and improved vascular endothelial function in people with stable coronary heart disease. However, there was no effect on endothelium-independent function. Water-based exercise appears to be an effective alternative to gym-based exercise for people with coronary heart disease, which has specific benefits to vascular health and function.
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Enfermedad Coronaria , Agua , Humanos , Vasodilatación , Endotelio Vascular , Ejercicio Físico , Arteria BraquialRESUMEN
As men age, serum testosterone (T) concentrations decrease, as do fitness, strength, and lean mass. Whether testosterone treatment confers additive benefit to reverse these changes when combined with exercise training in middle-to-older aged men remains unclear. We assessed the effects of T treatment and exercise, alone and in combination, on aerobic capacity (VÌo2peak), body composition, and muscular strength in men 50-70 yr, waist circumference ≥95 cm and low-normal serum T (6-14 nmol·L-1). Participants (n = 80) were randomized to AndroForte5 (testosterone 5.0% wt/vol, 100 mg/2 mL) cream (T), or matching placebo (P), applied transdermally daily, and supervised center-based exercise (Ex) or no additional exercise (NEx), for 12-wk. Exercise increased VÌo2peak and strength versus nonexercise (VÌo2peak: T + Ex: +2.5 mL·kg-1·min-1, P + Ex: +3.2 mL·kg-1·min-1, P < 0.001; leg press: T + Ex: +31 kg, P + Ex: +24 kg, P = 0.006). T treatment did not affect VÌo2peak or strength. Exercise decreased total (T + Ex: -1.7, P + Ex: -2.3 kg, P < 0.001) and visceral fat (T + Ex: -0.1 kg, P + Ex: -0.3 kg, P = 0.003), and increased total (T + Ex: +1.4 kg, P + Ex: +0.7 kg, P = 0.008) and arm lean mass (T + Ex: +0.5 kg, P + Ex: +0.3 kg, P = 0.024). T treatment did not affect total or visceral fat, but increased total (T + Ex: +1.4 kg, T + NEx: +0.7 kg, P = 0.015), leg (T + Ex: +0.3 kg, T + NEx: +0.2 kg, P = 0.024), and arm lean mass (T + Ex: +0.5 kg, T + NEx: +0.2 kg, P = 0.046). T + Ex increased arm lean mass (T + Ex: +0.5 kg vs. P + NEx: -0.0 kg, P = 0.001) and leg strength (T + Ex: +31 kg vs. P + NEx: +12 kg, P = 0.032) compared with P + NEx, with no other additive effects. Exercise training was more effective than T treatment in increasing aerobic capacity and decreasing total and visceral fat mass. T treatment at therapeutic doses increased lean mass but conferred limited additional benefit when combined with exercise. Exercise should be evaluated as an antiaging intervention in preference to testosterone treatment in men.NEW & NOTEWORTHY We illustrate that exercise training generates superior outcomes to testosterone treatment for improving aerobic fitness, muscular strength, and total and visceral fat mass in men 50-70 yr with low-normal serum testosterone concentrations. Adding testosterone treatment to exercise did not provide any additive benefit for these variables. Testosterone treatment alone and exercise alone had similar impacts on lean mass. Therefore, men unable to exercise may obtain benefit from testosterone treatment alone to improve lean mass.
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Composición Corporal/fisiología , Ejercicio Físico/fisiología , Fuerza Muscular/fisiología , Aptitud Física/fisiología , Testosterona/sangre , Anciano , Humanos , Masculino , Persona de Mediana EdadRESUMEN
CONTEXT: With age, testosterone (T) and physical activity levels often decline in parallel. The effect of combining T treatment and exercise training on ambulatory blood pressure (ABP) is unclear. OBJECTIVE: To assess T and exercise effects, alone and in combination, on ABP in men aged 50-70 years, waist circumference ≥ 95 cm and low-normal serum T (6-14 nmol/L), without organic hypogonadism. DESIGN: A 2 × 2 factorial randomised, placebo-controlled study. INTERVENTION: Randomization to daily transdermal AndroForte5® (Testosterone 5.0%w/v, 100 mg in 2 ml) cream (T), or matching placebo (P) (double-blind), and to supervised exercise (Ex) or no additional exercise (NEx), for 12 weeks. RESULTS: Average 24-h systolic blood pressure (SBP) increased with T treatment (testosterone*time, p = .035). Average 24-h SBP increased in T+Ex (T+Ex:+3.0 vs. P+NEx: -3.0 mmHg, p = .026) driven by day-time changes (T+Ex:+3.5 vs. P+NEx: -3.0 mmHg, p = .026). There was an effect of T for 24-h average diastolic blood pressure (DBP, testosterone*time, p = .044) driven by the decrease in P+Ex (P+Ex: -3.9 vs. T+NEx: -0.5 mmHg, p = .015). Night-time DBP was lower with exercise (P+Ex: -4.0 vs. P+NEx: +0.7 mmHg, p = .032). The effect of exercise to lower night-time DBP was not apparent in the presence of T (T+Ex: -0.4 vs. P+NEx: +0.7 mmHg, p > .05). Ex increased average 24-h pulse pressure (PP, exercise*time, p = .022), largely during daytime hours (exercise*time, p = .013). CONCLUSIONS: There was a main effect of T to increase 24-h SBP, primarily seen when T was combined with Ex. Exercise alone decreased 24-h and night-time DBP; an effect attenuated by T. BP should be carefully assessed and monitored, when prescribing T treatment to middle-aged and older men, especially when combined with exercise training.
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Monitoreo Ambulatorio de la Presión Arterial , Hipertensión , Anciano , Presión Sanguínea , Ejercicio Físico , Humanos , Masculino , Persona de Mediana Edad , TestosteronaRESUMEN
[Figure: see text].
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Terapia por Ejercicio/métodos , Obesidad Abdominal , Testosterona , Vasodilatación , Administración Cutánea , Anciano , Terapia por Observación Directa , Monitoreo de Drogas/métodos , Hormonas Gonadales/administración & dosificación , Hormonas Gonadales/sangre , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico/métodos , Obesidad Abdominal/diagnóstico , Obesidad Abdominal/metabolismo , Obesidad Abdominal/fisiopatología , Obesidad Abdominal/terapia , Testosterona/administración & dosificación , Testosterona/sangre , Resultado del Tratamiento , Vasodilatación/efectos de los fármacos , Vasodilatación/fisiologíaRESUMEN
Background: Despite developments in surgical techniques and medical care, people with a Fontan circulation still experience long-term complications; non-invasive therapies to optimize the circulation have not been established. Exercise intolerance affects the majority of the population and is associated with worse prognosis. Historically, people living with a Fontan circulation were advised to avoid physical activity, but a small number of heterogenous, predominantly uncontrolled studies have shown that exercise training is safe-and for unique reasons, may even be of heightened importance in the setting of Fontan physiology. The mechanisms underlying improvements in aerobic exercise capacity and the effects of exercise training on circulatory and end-organ function remain incompletely understood. Furthermore, the optimal methods of exercise prescription are poorly characterized. This highlights the need for large, well-designed, multi-center, randomized, controlled trials. Aims and Methods: The Fontan Fitness Intervention Trial (F-FIT)-a phase III clinical trial-aims to optimize exercise prescription and delivery in people with a Fontan circulation. In this multi-center, randomized, controlled study, eligible Fontan participants will be randomized to either a 4-month supervised aerobic and resistance exercise training program of moderate-to-vigorous intensity followed by an 8-month maintenance phase; or usual care (control group). Adolescent and adult (≥16 years) Fontan participants will be randomized to either traditional face-to-face exercise training, telehealth exercise training, or usual care in a three-arm trial with an allocation of 2:2:1 (traditional:telehealth:control). Children (<16 years) will be randomized to either a physical activity and exercise program of moderate-to-vigorous intensity or usual care in a two-arm trial with a 1:1 allocation. The primary outcome is a change in aerobic exercise capacity (peak oxygen uptake) at 4-months. Secondary outcomes include safety, and changes in cardiopulmonary exercise testing measures, peripheral venous pressure, respiratory muscle and lung function, body composition, liver stiffness, neuropsychological and neurocognitive function, physical activity levels, dietary and nutritional status, vascular function, neurohormonal activation, metabolites, cardiac function, quality of life, musculoskeletal fitness, and health care utilization. Outcome measures will be assessed at baseline, 4-months, and 12-months. This manuscript will describe the pathophysiology of exercise intolerance in the Fontan circulation and the rationale and protocol for the F-FIT.
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PURPOSE: To investigate the effects of 8 wk of upright water-based exercise training in people with type 2 diabetes. METHODS: Thirteen participants with type 2 diabetes (54% male; 60.9 ± 9.6 yr, mean ± standard deviation) completed 8 wk of upright water-based exercise training at a moderate intensity (60%-80% of exercise test-derived maximum HR), for 1 h, three times a week (TG). Fourteen participants (64% male; 63.9 ± 9.8 yr) acted as a control group (CG) who maintained their usual activities. Preintervention and postintervention, participants performed cardiopulmonary exercise testing to determine VËO2peak and one-repetition maximum testing to assess muscular strength. Blood profiles were assessed with standard assays. Body mass index and waist/hip ratio were employed as measures of anthropometry. Endothelium-dependent (brachial artery flow-mediated dilation) and independent (glyceryl trinitrate-mediated) function were assessed using vascular ultrasound. RESULTS: Water-based training increased VËO2peak (18.5 ± 4.3 mL·kg·min to 21.5 ± 5.4 mL·kg·min) (P = 0.002), overall muscle strength (123 ± 44 kg to 139 ± 43 kg) and leg strength (92 ± 28 kg to 104 ± 29 kg), compared with the CG (P = 0.001). The effect on pectoral strength (31 ± 17 kg to 35 ± 16 kg) was not significantly different to the CG (24 ± 12 kg to 26 ± 14 kg) (P = 0.08). No change was observed in anthropometry, blood profiles, or glyceryl trinitrate-mediated vascular function. Flow-mediated dilation was increased after training (6.1% ± 2.4% to 6.5% ± 3.0%), compared with controls who demonstrated a slight decrease (6.2% ± 1.6% to 5.4% ± 1.6%) (P = 0.002). CONCLUSIONS: Water-based circuit training was well tolerated and appears to be an effective exercise modality for improving aerobic fitness, strength, and vascular function in people with type 2 diabetes.
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Ejercicio en Circuitos/métodos , Diabetes Mellitus Tipo 2/terapia , Terapia por Ejercicio/métodos , Anciano , Antropometría , Glucemia/metabolismo , Arteria Braquial/fisiología , Capacidad Cardiovascular/fisiología , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Humanos , Lípidos/sangre , Masculino , Persona de Mediana Edad , Fuerza Muscular/fisiología , Vasodilatación , AguaRESUMEN
Cerebral blood flow during exercise is impaired in patients with heart failure implanted with left ventricular assist devices (LVADs). Our aim was to determine whether a 3-mo exercise training program could mitigate cerebrovascular dysfunction. Internal carotid artery (ICA) blood flow and intracranial middle (MCAv) and posterior cerebral (PCAv) artery velocities were measured continuously using Doppler ultrasound, alongside cardiorespiratory measures at rest and in response to an incremental cycle ergometer exercise protocol in 12 LVAD participants (5 female, 53.6 ± 11.8 yr; 84.2 ± 15.7 kg; 1.73 ± 0.08) pre- (PreTR) and post- (PostTR) completion of a 3-mo supervised exercise rehabilitation program. At rest, only PCAv was different PostTR (38.1 ± 10.4 cm/s) compared with PreTR (43.0 ± 10.8 cm/s; P < 0.05). PreTR, the reduction in PCAv observed from rest to exercise (5.2 ± 1.8%) was mitigated PostTR (P < 0.001). Similarly, exercise training enhanced ICA flow during submaximal exercise (~8.6 ± 13.7%), resulting in increased ICA flow PostTR compared with a reduced flow PreTR (P < 0.001). Although both end-tidal partial pressure of carbon dioxide and mean arterial pressure responses during incremental exercise were greater PostTR than PreTR, only the improved PETCO2 was related to the improved ICA flow (R2 = 0.14; P < 0.05). Our findings suggest that short-term exercise training improves cerebrovascular function during exercise in patients with LVADs. This finding should encourage future studies investigating long-term exercise training and cerebral and peripheral vascular adaptation.NEW & NOTEWORTHY Left ventricular assist devices, now used as destination therapy in end-stage heart failure, enable patients to undertake rehabilitative exercise training. We show, for the first time in humans, that training improves cerebrovascular function during exercise in patients with left ventricular assist devices. This finding may have implications for cerebrovascular health in patients with heart failure.
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Circulación Cerebrovascular/fisiología , Terapia por Ejercicio/métodos , Insuficiencia Cardíaca/terapia , Corazón Auxiliar/estadística & datos numéricos , Adaptación Fisiológica , Velocidad del Flujo Sanguíneo , Femenino , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/rehabilitación , Hemodinámica , Humanos , Masculino , Persona de Mediana Edad , Función Ventricular Izquierda/fisiologíaRESUMEN
BACKGROUND: Exercise training is an important component of multidisciplinary heart failure management. However, the effects of aerobic training (AT) versus resistance training (RT) on cardiac function in patients with heart failure with reduced ejection fraction are not well defined. The aim of this study was to evaluate the impact of these exercise modalities on echocardiographic parameters. METHODS: Participants with stable heart failure with reduced ejection fraction (ejection fraction < 50%) were randomized to 12 weeks of AT, RT, or untrained control. Exercise was performed at matched relative intensities of each training modality (50%-70% of maximum). Echocardiography and cardiopulmonary exercise testing were performed at baseline and after 12 weeks of training. RESULTS: Thirty-eight participants were randomized, and 12 in each group completed the intervention (mean age, 61.5 ± 1.7 years; 89% men). Peak oxygen consumption increased from 14.5 ± 1.3 to 17.2 ± 1.6 ml · min-1 · kg-1 after AT and from 13.7 ± 1.2 to 16.4 ± 1.1 ml · min-1 · kg-1 after RT (P < .001 for both). In the AT group, there was a decrease in septal e' (from 0.052 ± 0.004 to 0.041 ± 0.004 m/sec) and increases in E/e' ratio (from 18.2 ± 3.1 to 23.8 ± 3.5), left atrial volume (from 86 ± 9 to 99 ± 10 mL), and right ventricular end-diastolic area (from 18 ± 1 to 20 ± 1 cm2; P < .05 for all), but these were unchanged in the control and RT groups. There were no significant changes in left ventricular diameters or volumes or right ventricular fractional area change after exercise. CONCLUSIONS: There is a differential effect of AT versus RT on some echocardiographic parameters in patients with heart failure with reduced ejection fraction. AT was associated with evidence of worsening myocardial diastolic function, whereas this was not apparent after RT. Further studies are indicated to investigate the long-term clinical significance of these adaptations.
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Ecocardiografía/métodos , Terapia por Ejercicio/métodos , Ejercicio Físico/fisiología , Insuficiencia Cardíaca/diagnóstico , Ventrículos Cardíacos/fisiopatología , Volumen Sistólico/fisiología , Femenino , Estudios de Seguimiento , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/rehabilitación , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
This study examined the acute performance, cardiovascular and local muscular responses to perceived exertion-based high-intensity interval exercise using either double- or single-leg cycling. Fifteen healthy middle-aged adults completed, on separate occasions, ten 30-s double-leg intervals interspersed with 60â s passive recovery and twenty (ten with each leg) 30-s single-leg intervals interspersed with 60â s passive recovery. Impedance cardiography, blood pressure, muscle oxygenation and total haemoglobin content (near-infrared spectroscopy), oxygen consumption and power output were measured throughout each session. Normalised to the lean mass used during each trial, single-leg cycling resulted in lower power output (single-leg: 8.92 ± 1.74â Wâ kg-1 and double-leg: 10.41 ± 3.22â Wâ kg-1; p < 0.05) but greater oxygen consumption (single-leg: 103 ± 11â mLâ kg-1â min-1 and double-leg: 84 ± 21â mLâ kg-1â min-1; p < 0.01) and cardiac output (single-leg: 1407 ± 334â mLâ kg-1â min-1 and double-leg: 850 ± 222â mLâ kg-1â min-1; p < 0.01), compared with double-leg cycling. Mean arterial pressure (double-leg: 108 ± 11â mmHg and single-leg: 102 ± 10â mmHg), change in total haemoglobin content (double-leg: 8.76 ± 10.65â µMâ cmâ s-1 and single-leg: 13.42 ± 4.10â µMâ cmâ s-1) and change in tissue oxygenation index (double-leg: -4.51 ± 3.56% and single-leg: -3.97 ± 3.91%) were not different between double-leg and single-leg cycling. When compared to double-leg cycling, single-leg cycling elicited a higher cardiac output relative to the lean mass, but this did not result in greater power output. The dissociation between blood availability and power output is consistent with an ageing model characterised by a decrease in local oxygen delivery and distribution capability.
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Ciclismo/fisiología , Gasto Cardíaco , Prueba de Esfuerzo/métodos , Entrenamiento de Intervalos de Alta Intensidad/métodos , Extremidad Inferior/irrigación sanguínea , Músculo Esquelético/irrigación sanguínea , Presión Sanguínea , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Consumo de Oxígeno , Espectroscopía Infrarroja CortaRESUMEN
INTRODUCTION: Regular exercise can reduce the risk of developing cardiovascular disease through risk factor modification, with high-intensity exercise and more recently small muscle mass training providing alternatives to moderate-intensity exercise. METHODS: This study randomly assigned 53 healthy middle-age adults (age, 62 ± 6 yr) to complete 24 sessions (8 wk; 3 d·wk) of exercise training, using either high-intensity double-leg cycling (n = 17; HITDL), high-intensity single-leg cycling (n = 18; HITSL), or moderate-intensity double-leg cycling (n = 18; MCTDL). Biomarkers of cardiovascular risk (total cholesterol, triglycerides, HDL-c, LDL-c, apo-B48, and glucose), anthropometry measures (body mass, body mass index, waist circumference, and waist-to-hip ratio), resting blood pressure, and aerobic capacity were assessed pre- and postintervention. RESULTS: Total work completed was greater (P < 0.01) in MCTDL (5938 ± 1462 kJ) compared with the HITDL (3462 ± 1063 kJ) and HITSL (4423 ± 1875 kJ). Pre- to posttraining differences were observed for waist-to-hip ratio (0.84 ± 0.09 vs 0.83 ± 0.09; P < 0.01), resting systolic blood pressure (129 ± 11 vs 124 ± 12 mm Hg; P < 0.01), total cholesterol (5.87 ± 1.17 vs 5.55 ± 0.98 mmol·L; P < 0.01), and LDL-c (3.70 ± 1.04 vs 3.44 ± 0.84 mmol·L; P < 0.01), with no differences between conditions. In addition, aerobic capacity increased after training (22.3 ± 6.4 vs 24.9 ± 7.6 mL·kg·min; P < 0.01), with no differences between conditions. CONCLUSION: These findings suggest that all three modes of exercise can be prescribed to achieve cardiovascular risk reduction in an aging population.
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Ciclismo/fisiología , Enfermedades Cardiovasculares/prevención & control , Acondicionamiento Físico Humano/métodos , Acondicionamiento Físico Humano/fisiología , Antropometría , Biomarcadores/sangre , Glucemia/metabolismo , Presión Sanguínea/fisiología , Colesterol/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Receptores de Lipoproteína/sangre , Factores de Riesgo , Triglicéridos/sangreRESUMEN
INTRODUCTION: In healthy individuals, cerebral blood flow (CBF) increases during exercise, but few studies have compared changes in CBF during exercise in patients with heart failure (HF) to healthy controls (CTRL) or assessed the effects of left ventricular assist devices (LVAD). We hypothesized that subjects implanted with LVAD would exhibit impaired cerebrovascular responses to cycle exercise when compared with age- and sex-matched healthy CTRL subjects but would have enhanced responses relative to subjects with HF. METHODS: Internal carotid artery (ICA) blood flow and intracranial middle (MCAv) and posterior cerebral (PCAv) artery velocities were measured continuously using Doppler ultrasound, alongside cardiorespiratory measures at rest and in response to an incremental submaximal cycle ergometer exercise protocol in nine LVAD participants (58 ± 15 yr, 87 ± 16 kg, 172 ± 8 cm, six females), nine age- and sex-matched subjects with HF (58 ± 8 yr, 84 ± 11 kg, 177 ± 6 cm), and nine CTRL (55 ± 14 yr, 74 ± 16 kg, 168 ± 10 cm). RESULTS: At rest, ICA hemodynamics (velocity, shear rate, and flow) were greater in CTRL and LVAD than that in HF (P < 0.05). Higher MCAv (+5.52 ± 1.59 cm·s, P = 0.003) and PCAv (+5.82 ± 1.41 cm·s, P = 0.001) were also observed in LVAD subjects than healthy CTRL. During exercise, ICA flow increased at all workloads in CTRL, but not in HF or LVAD groups. MCAv increased from baseline in both HF and CTRL participants (P = 0.0001), but not in LVAD subjects. Nonetheless, CTRL and LVAD showed higher MCAv (P = 0.006) and PCAv (P < 0.0001) values throughout exercise than HF. CONCLUSION: Our findings indicate that LVAD subjects exhibit higher CBF at rest and during exercise than matched HF participants but attenuated brain blood flows during exercise when compared with healthy subjects. CBF should be considered when designing exercise training interventions in patients with HF and LVAD.
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Circulación Cerebrovascular/fisiología , Ejercicio Físico/fisiología , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/rehabilitación , Corazón Auxiliar , Adulto , Anciano , Velocidad del Flujo Sanguíneo/fisiología , Arteria Carótida Interna/diagnóstico por imagen , Arteria Carótida Interna/fisiología , Femenino , Insuficiencia Cardíaca/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Arteria Cerebral Media/diagnóstico por imagen , Arteria Cerebral Media/fisiología , Arteria Cerebral Posterior/diagnóstico por imagen , Arteria Cerebral Posterior/fisiología , Pruebas de Función Respiratoria , Ultrasonografía Doppler DúplexRESUMEN
Regular exercise improves health but can also induce adverse responses. Although such episodes are rare, many guidelines for pre-participation exercise screening have historically had a low threshold for recommending medical clearance prior to the commencement of exercise, placing the responsibility for decision making about exercise participation on physicians. The 'clearance to exercise' model still occurs widely in practice, but creates cost burdens and barriers to the uptake of exercise. Moreover, many physicians are not provided the training, nor time in a standard consultation, to be able to effectively perform this role. We present a model for pre-participation exercise screening and the initial assessment of clients wishing to commence an exercise programme. It is designed to guide professional practice for the referral, assessment and prescription of exercise for people across the health spectrum, from individuals who are apparently healthy, through to clients with pre-existing or occult chronic conditions. The model removes the request that physicians provide a 'clearance' for patients to engage in exercise programmes. Instead the role of physicians is identified as providing relevant clinical guidance to suitably qualified exercise professionals to allow them to use their knowledge, skills and expertise in exercise prescription to assess and manage any risks related to the prescription and delivery of appropriate exercise programmes. It is anticipated that removing unjustified barriers to exercise participation, such as mandated medical review, will improve the uptake of exercise by the unacceptably high proportion of the population who do not undertake sufficient physical activity for health benefit.
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Ejercicio Físico , Relaciones Interprofesionales , Tamizaje Masivo/métodos , Aptitud Física , Médicos , Australia , Enfermedad Crónica , Consenso , Terapia por Ejercicio , Humanos , Tamizaje Masivo/normas , Nueva Zelanda , Encuestas y Cuestionarios/normasRESUMEN
The purpose of this study was to assess whether changes in physical fitness relate to changes in cardiovascular risk factors following standardized, center-based and supervised exercise training programs in subjects with increased cardiovascular risk. We pooled data from exercise training studies of subjects with increased cardiovascular risk (n = 166) who underwent 8-52 weeks endurance training. We determined fitness (i.e., peak oxygen uptake) and traditional cardiovascular risk factors (body mass index, blood pressure, total cholesterol, high-density lipoprotein cholesterol), before and after training. We divided subjects into quartiles based on improvement in fitness, and examined whether these groups differed in terms of risk factors. Associations between changes in fitness and in cardiovascular risk factors were further tested using Pearson correlations. Significant heterogeneity was apparent in the improvement of fitness and individual risk factors, with nonresponder rates of 17% for fitness, 44% for body mass index, 33% for mean arterial pressure, 49% for total cholesterol, and 49% for high-density lipoprotein cholesterol. Neither the number, nor the magnitude, of change in cardiovascular risk factors differed significantly between quartiles of fitness change. Changes in fitness were not correlated with changes in cardiovascular risk factors (all P > 0.05). Our data suggest that significant heterogeneity exists in changes in peak oxygen uptake after training, while improvement in fitness did not relate to improvement in cardiovascular risk factors. In subjects with increased cardiovascular risk, improvements in fitness are not obligatory for training-induced improvements in cardiovascular risk factors.
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Capacidad Cardiovascular , Enfermedades Cardiovasculares/prevención & control , Acondicionamiento Físico Humano/métodos , Adulto , Anciano , Presión Sanguínea , Índice de Masa Corporal , Enfermedades Cardiovasculares/fisiopatología , HDL-Colesterol/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Consumo de OxígenoRESUMEN
INTRODUCTION: Leg order during sequential single-leg cycling (i.e., exercising both legs independently within a single session) may affect local muscular responses potentially influencing adaptations. This study examined the cardiovascular and skeletal muscle hemodynamic responses during double-leg and sequential single-leg cycling. METHODS: Ten young healthy adults (28 ± 6 yr) completed six 1-min double-leg intervals interspersed with 1 min of passive recovery and, on a separate occasion, 12 (six with one leg followed by six with the other leg) 1-min single-leg intervals interspersed with 1 min of passive recovery. Oxygen consumption, heart rate, blood pressure, muscle oxygenation, muscle blood volume, and power output were measured throughout each session. RESULTS: Oxygen consumption, heart rate, and power output were not different between sets of single-leg intervals, but the average of both sets was lower than the double-leg intervals. Mean arterial pressure was higher during double-leg compared with sequential single-leg intervals (115 ± 9 vs 104 ± 9 mm Hg, P < 0.05) and higher during the initial compared with second set of single-leg intervals (108 ± 10 vs 101 ± 10 mm Hg, P < 0.05). The increase in muscle blood volume from baseline was similar between the active single leg and the double leg (267 ± 150 vs 214 ± 169 µM·cm, P = 0.26). The pattern of change in muscle blood volume from the initial to second set of intervals was significantly different (P < 0.05) when the leg was active in the initial (-52.3% ± 111.6%) compared with second set (65.1% ± 152.9%). CONCLUSIONS: These data indicate that the order in which each leg performs sequential single-leg cycling influences the local hemodynamic responses, with the inactive muscle influencing the stimulus experienced by the contralateral leg.
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Prueba de Esfuerzo/métodos , Hemodinámica , Pierna/irrigación sanguínea , Músculo Esquelético/irrigación sanguínea , Adulto , Presión Sanguínea , Estudios Cruzados , Femenino , Frecuencia Cardíaca , Humanos , Pierna/fisiología , Masculino , Músculo Esquelético/fisiología , Consumo de Oxígeno , Adulto JovenRESUMEN
PURPOSE: Chronic heart failure (CHF) is characterized by dyspnea and poor exercise tolerance, which decreases aerobic capacity (VËO2peak), a measure strongly correlated with quality of life and mortality. In healthy populations, eccentric (ECC) cycling can be performed at a lower oxygen demand for matched workload, compared with concentric (CON) cycling, but few studies have previously investigated ECC cycling in CHF. We hypothesized that, when matched for external workload (W), an ECC cycling bout would be performed at a lower cardiorespiratory load (VËO2) than CON in patients with CHF. METHODS: Eleven CHF patients (10 males) with impaired left ventricular systolic function (ejection fraction 31% ± 12%) completed a CON VËO2peak test, with the subsequent ECC and CON protocols set at 70% of individual maximal CON power (W). Oxygen consumption (VËO2), RER, minute ventilation (VËE), HR, and rate pressure product were compared between conditions. RESULTS: ECC was performed at a lower VËO2 (12.3 ± 1.3 vs 14.1 ± 0.8 mL·kg·min, P = 0.01), RER (0.92 ± 0.02 vs 0.96 ± 0.01, P = 0.01), and VËE (36.5 ± 4.4 vs 40.2 ± 2.0 L·min, P = 0.04) in comparison with CON, despite both conditions being performed at matched workloads. HR (101 ± 5 vs 96 ± 1 bpm, P = 0.06) and rate pressure product (13,539 ± 788 vs 11,911 ± 227 bpm·mm Hg, P = 0.15) were not significantly different between conditions. CONCLUSION: When matched for external workload, ECC cycling can be performed with a lower oxygen demand than CON in patients with CHF. Eccentric cycling is a promising modality for cardiac rehabilitation in severely deconditioned patients with CHF.
Asunto(s)
Ciclismo/fisiología , Tolerancia al Ejercicio/fisiología , Insuficiencia Cardíaca/fisiopatología , Consumo de Oxígeno , Presión Sanguínea , Enfermedad Crónica , Prueba de Esfuerzo/métodos , Femenino , Insuficiencia Cardíaca/rehabilitación , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana Edad , Mialgia/etiologíaRESUMEN
BACKGROUND: Alterations in skeletal muscle function and architecture have been linked to the compromised exercise capacity characterizing chronic heart failure (CHF). However, how passive skeletal muscle force is affected in CHF is not clear. Understanding passive force characteristics in CHF can help further elucidate the extent to which altered contractile properties and/or architecture might affect muscle and locomotor function. Therefore, the aim of this study was to investigate passive force in a single muscle for which non-invasive measures of muscle size and estimates of fiber force are possible, the soleus (SOL), both in CHF patients and age- and physical activity-matched control participants. METHODS: Passive SOL muscle force and size were obtained by means of a novel approach combining experimental data (dynamometry, electromyography, ultrasound imaging) with a musculoskeletal model. RESULTS: We found reduced passive SOL forces (â¼30%) (at the same relative levels of muscle stretch) in CHF vs. healthy individuals. This difference was eliminated when force was normalized by physiological cross sectional area, indicating that reduced force output may be most strongly associated with muscle size. Nevertheless, passive force was significantly higher in CHF at a given absolute muscle length (non length-normalized) and likely explained by the shorter muscle slack lengths and optimal muscle lengths measured in CHF compared to the control participants. This later factor may lead to altered performance of the SOL in functional tasks such gait. DISCUSSION: These findings suggest introducing exercise rehabilitation targeting muscle hypertrophy and, specifically for the calf muscles, exercise that promotes muscle lengthening.
RESUMEN
We propose the hypothesis that soleus muscle function may provide a surrogate measure of functional capacity in patients with heart failure. We summarize literature pertaining to skeletal muscle as a locus of fatigue and present our recent findings, using in vivo imaging in combination with biomechanical experimentation and modeling, to reveal novel structure-function relationships in chronic heart failure skeletal muscle and gait.
Asunto(s)
Insuficiencia Cardíaca/fisiopatología , Músculo Esquelético/fisiopatología , Fenómenos Biomecánicos , Ejercicio Físico/fisiología , Fatiga/fisiopatología , Marcha/fisiología , Indicadores de Salud , Humanos , Músculo Esquelético/anatomía & histologíaRESUMEN
High-intensity interval exercise (HIIE) has gained popularity in recent years for patients with cardiovascular and metabolic diseases. Despite potential benefits, concerns remain about the safety of the acute response (during and/or within 24 hours postexercise) to a single session of HIIE for these cohorts. Therefore, the aim of this study was to perform a systematic review to evaluate the safety of acute HIIE for people with cardiometabolic diseases. Electronic databases were searched for studies published prior to January 2015, which reported the acute responses of patients with cardiometabolic diseases to HIIE (≥80% peak power output or ≥85% peak aerobic power, VO2peak). Eleven studies met the inclusion criteria (n = 156; clinically stable, aged 27-66 years), with 13 adverse responses reported (~8% of individuals). The rate of adverse responses is somewhat higher compared to the previously reported risk during moderate-intensity exercise. Caution must be taken when prescribing HIIE to patients with cardiometabolic disease. Patients who wish to perform HIIE should be clinically stable, have had recent exposure to at least regular moderate-intensity exercise, and have appropriate supervision and monitoring during and after the exercise session.