cardiac output exercise

The muscle metaboreflex stimulates the elevation of arterial blood pressure, aiming to rectify the oxygen deficit by enhancing oxygen delivery to support muscle activity. Moreover, activating the muscle metaboreflex significantly increases cardiac output (CO) by increasing factors such as heart rate, ventricular contractility, preload, stroke volume and mobilization of central blood volume. Previous studies indicate that ageing and cardiovascular diseases modify the muscle metaboreflex during exercise, limiting the ability to increase CO during physical activity...

OBJECTIVE: To compare the characteristics of "responders" and "non-responders" to 8-weeks of exercise training to determine differences in key cardiovascular disease outcomes in people with coronary artery disease (CAD). DESIGN: Secondary analysis of data from the HIIT or MISS UK trial. SETTING: Six outpatient National Health Service cardiac rehabilitation centers in the UK. In people with CAD attending cardiac rehabilitation, the HIIT or MISS UK trial reported that short-term, low-volume, high intensity interval training (HIIT) was more effective than moderate intensity steady state (MISS) exercise training for improving peak oxygen uptake (VO2 peak)...

To evaluate the morphology of the "athlete's heart", left ventricular (LV) wall thickness (WT) and end-diastolic internal diameter (LVIDd) at rest were addressed in publications on skiers, rowers, swimmers, cyclists, runners, weightlifters (n = 927), and untrained controls (n = 173) and related to the acute and maximal cardiovascular response to their respective disciplines. Dimensions of the heart at rest and functional variables established during the various sport disciplines were scaled to body weight for comparison among athletes independent of body mass...

BACKGROUND: Supervised exercise training decreases total and cardiac mortality and increases quality of life of heart failure with reduced ejection fraction (HFrEF) patients. However, response to training is variable from one patient to another and factors responsible for a positive response to training remain unclear. The aims of the study were to compare cardiac hemodynamic changes after an exercise training program in responders (R) versus non-responders (NR) HFrEF patients, and to compare different discriminators used to assess response to training...

The ability to increase cardiac output during dynamic exercise is paramount for the ability to maintain workload performance. Reflex control of the cardiovascular system during exercise is complex and multifaceted involving multiple feedforward and feedback systems. One major reflex thought to mediate the autonomic adjustments to exercise is termed the muscle metaboreflex and is activated via afferent neurons within active skeletal muscle which respond to the accumulation of interstitial metabolites during exercise when blood flow and O2 delivery are insufficient to meet metabolic demands...

This study aimed to determine the effect of supervised exercise training (SET) on cardiovascular function in patients with intermittent claudication (IC). A systematic search in MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases was conducted. Primary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), rate pressure product (RPP), cardiac output (CO), peak oxygen consumption (VO2peak ), and heart rate variability (HRV). Secondary outcomes were maximum walking distance (MWD) and pain-free walking distance (PFWD)...

Few formulas have been used in exercise physiology as extensively as the Fick formula, which calculates the rate of oxygen consumption ( i.e. , V.O2 ) as the product of cardiac output (Q.) and the difference in oxygen content in arterial and mixed venous blood (Δa<mml:math xmlns:mml="https://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mover><mml:mi>v</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:mrow></mml:math>O2 ). Unfortunately, the physiology of maximum V...

Early in the twentieth century, Walter B. Cannon (1871-1945) introduced his overarching hypothesis of "homeostasis" (Cannon 1932)-the ability to sustain physiological values within a narrow range necessary for life during periods of stress. Physical exercise represents a stress in which motor, respiratory and cardiovascular systems must be integrated across a range of metabolic stress to match oxygen delivery to oxygen need at the cellular level, together with appropriate thermoregulatory control, blood pressure adjustments and energy provision...

Cardiovascular responses to diving are characterized by two opposing responses: tachycardia resulting from exercise and bradycardia resulting from the apnea. The convergence of bradycardia and tachycardia may determine the cardiovascular responses to diving. The purpose of this study was to investigate the interaction of breath holding and muscle mechanoreflex on cardiovascular responses in breath-hold divers (BHDs) and non-BHDs. We compared the cardiovascular responses to combined apnea and the mechanoreflex in BHDs and non-BHDs...

AIM: Exercise intolerance is the central symptom in patients with heart failure with preserved ejection fraction. In the present study, we investigated the adrenergic reserve both in vivo and in cardiomyocytes of a murine cardiometabolic HFpEF model. METHODS: 12-week-old male C57BL/6J mice were fed regular chow (control) or a high-fat diet and L-NAME (HFpEF) for 15 weeks. At 27 weeks, we performed (stress) echocardiography and exercise testing and measured the adrenergic reserve and its modulation by nitric oxide and reactive oxygen species in left ventricular cardiomyocytes...

AIMS: To perform a network meta-analysis to determine the effectiveness of lifestyle interventions on exercise tolerance and quality of life (QoL) in people with HFpEF. METHODS: Ten databases were searched for randomised controlled trials that evaluated a diet and/or exercise intervention in people with HFpEF up until May 2022. The co-primary outcomes were peak oxygen uptake (V̇O2peak ) and QoL as assessed by the Minnesota Living with Heart Failure Questionnaire (MLHFQ)...

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The left atrium (LA) mediates cardiopulmonary interactions. During ventricular systole, the LA functions as a compliant reservoir that is coupled to the left ventricle (LV) and offloads volume from the pulmonary vasculature. We aimed to describe LA reservoir function using phasic relationships between pulmonary artery wedge pressure (PAWP) and LA volume events. We included healthy adults (7M/6F, 56±8 years) who were studied at rest and during semi-recumbent cycle ergometry at a target 100 b/min. heart rate...

BACKGROUND: Recent guidelines redefined exercise pulmonary hypertension as a mean pulmonary artery pressure/cardiac output (mPAP/CO) slope >3 mm Hg·L-1 ·min-1 . A peak systolic pulmonary artery pressure >60 mm Hg during exercise has been associated with an increased risk of cardiovascular death, heart failure rehospitalization, and aortic valve replacement in aortic valve stenosis. The prognostic value of the mPAP/CO slope in aortic valve stenosis remains unknown...

Acute hypoxia increases pulmonary arterial (PA) pressures, though its effect on right ventricular (RV) function is controversial. The objective of this study was to characterize exertional RV performance during acute hypoxia. Ten healthy participants (34 ± 10 years, 7 males) completed three visits: visits 1 and 2 included non-invasive normoxic (fraction of inspired oxygen ( <mml:math xmlns:mml="https://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msub><mml:mi>F</mml:mi> <mml:mrow><mml:mi>i</mml:mi> <mml:msub><mml:mi>O</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:mrow> </mml:msub> <mml:annotation>${F_{{\mathrm{i}}{{\mathrm{O}}_{\mathrm{2}}}}}$</mml:annotation></mml:semantics> </mml:math> ) = 0...

BACKGROUND: Cardiotoxicity is one of the most common adverse events of the chemotherapy. Physical exercise was shown to be cardioprotective. We aim to estimate the efficacy and safety of exercise in cancer patients receiving cardiotoxic chemotherapy. METHODS: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), which were retrieved by systematically searching PubMed, Web of Science, SCOPUS, Cochrane, Clinical Trials.gov, and MedRxiv through July 17th, 2023...

BACKGROUND: A comprehensive analysis was conducted on the relevant literature pertaining to the application of traditional Chinese exercises in stroke rehabilitation over the past 20 years. Additionally, a scientific knowledge map was created to elucidate the current research status, investigate its development process and research trends, and offer novel research perspectives for future studies. METHODS: The data is sourced from the WOS Core Collection, and CiteSpace software is used to analyze the relevant literature on traditional Chinese exercises in stroke rehabilitation...

BACKGROUND: Post-acute sequelae of COVID-19 (PASC) affect a significant proportion of patients who have previously contracted SARS-CoV-2, with exertional intolerance being a prominent symptom. This study aimed to characterise the invasive haemodynamic abnormalities of PASC-related exertional intolerance using invasive cardiopulmonary exercise testing (iCPET). STUDY DESIGN AND INTERVENTION: 55 patients were recruited from the Yale Post-COVID-19 Recovery Program, with most experiencing mild acute illness...

It is known that electrical muscle stimulation (EMS) can enhance physical function, but its impact on cognition and cerebral hemodynamics is not well-understood. Thus, the purpose of this study was to investigate the effects of one EMS session on cerebrovascular function and cognitive performance. The 17 recruited young healthy participants randomly undertook either a 25-min session of EMS or a resting control session (CTRL group). Cerebral blood flow velocity (CBFv) in the middle and posterior cerebral arteries (right MCAv and left PCAv, respectively), cerebral oxygenation, cardiac output and heart rate were measured throughout the sessions, while cognitive function was assessed before and after each experimental condition...

This study presents a closed-loop computational model to investigate the interplay between heart function, coronary flow, and systemic circulation during exercise, with a specific focus on the impact of coronary artery stenosis. The model incorporates a lumped representation of the heart, main arteries, and coronary arteries, establishing a closed circulatory system. The simulation investigates the autoregulation of coronary flow in response to myocardial oxygen demands during physical exercise by incorporating sympathetic and parasympathetic functions...