ABSTRACT
The analysis of ventilatory efficiency in cardiopulmonary exercise testing has proven useful for assessing the presence and severity of cardiorespiratory diseases. During exercise, efficient pulmonary gas exchange is characterized by uniform matching of lung ventilation with perfusion. By contrast, mismatching is marked by inefficient pulmonary gas exchange, requiring increased ventilation for a given CO2 production. The etiology of increased and inefficient ventilatory response to exercise in heart disease is multifactorial, involving both peripheral and central mechanisms. Exercise training has been recommended as non-pharmacological treatment for patients with different chronic cardiopulmonary diseases. In this respect, previous studies have reported improvements in ventilatory efficiency after aerobic exercise training in patients with heart disease. Against this background, the primary objective of the present review was to discuss the pathophysiological mechanisms involved in abnormal ventilatory response to exercise, with an emphasis on both patients with heart failure syndrome and coronary artery disease. Secondly, special focus was dedicated to the role of aerobic exercise training in improving indices of ventilatory efficiency among these patients, as well as to the underlying mechanisms involved.
Subject(s)
Coronary Artery Disease/physiopathology , Exercise/physiology , Heart Failure/physiopathology , Pulmonary Ventilation/physiology , Coronary Artery Disease/rehabilitation , Exercise Test , Exercise Therapy/methods , Female , Heart Failure/rehabilitation , Humans , Male , Oxygen Consumption/physiology , Pulmonary Gas Exchange/physiology , Time FactorsABSTRACT
The oxygen uptake efficiency slope (OUES) is a submaximal index incorporating cardiovascular, peripheral, and pulmonary factors that determine the ventilatory response to exercise. The purpose of this study was to evaluate the effects of continuous exercise training and interval exercise training on the OUES in patients with coronary artery disease. Thirty-five patients (59.3±1.8 years old; 28 men, 7 women) with coronary artery disease were randomly divided into two groups: continuous exercise training (n=18) and interval exercise training (n=17). All patients performed graded exercise tests with respiratory gas analysis before and 3 months after the exercise-training program to determine ventilatory anaerobic threshold (VAT), respiratory compensation point, and peak oxygen consumption (peak VO2). The OUES was assessed based on data from the second minute of exercise until exhaustion by calculating the slope of the linear relation between oxygen uptake and the logarithm of total ventilation. After the interventions, both groups showed increased aerobic fitness (P<0.05). In addition, both the continuous exercise and interval exercise training groups demonstrated an increase in OUES (P<0.05). Significant associations were observed in both groups: 1) continuous exercise training (OUES and peak VO2 r=0.57; OUES and VO2 VAT r=0.57); 2) interval exercise training (OUES and peak VO2 r=0.80; OUES and VO2 VAT r=0.67). Continuous and interval exercise training resulted in a similar increase in OUES among patients with coronary artery disease. These findings suggest that improvements in OUES among CAD patients after aerobic exercise training may be dependent on peripheral and central mechanisms.
Subject(s)
Coronary Artery Disease/metabolism , Exercise Therapy/methods , Exercise/physiology , Oxygen Consumption/physiology , Anaerobic Threshold/physiology , Analysis of Variance , Body Mass Index , Coronary Artery Disease/physiopathology , Coronary Artery Disease/rehabilitation , Exercise Test/methods , Female , Humans , Hypertension/physiopathology , Male , Middle Aged , Physical Conditioning, Human/methods , Physical Exertion/physiology , Program Evaluation/statistics & numerical data , Ventricular Function, LeftABSTRACT
The analysis of ventilatory efficiency in cardiopulmonary exercise testing has proven useful for assessing the presence and severity of cardiorespiratory diseases. During exercise, efficient pulmonary gas exchange is characterized by uniform matching of lung ventilation with perfusion. By contrast, mismatching is marked by inefficient pulmonary gas exchange, requiring increased ventilation for a given CO2 production. The etiology of increased and inefficient ventilatory response to exercise in heart disease is multifactorial, involving both peripheral and central mechanisms. Exercise training has been recommended as non-pharmacological treatment for patients with different chronic cardiopulmonary diseases. In this respect, previous studies have reported improvements in ventilatory efficiency after aerobic exercise training in patients with heart disease. Against this background, the primary objective of the present review was to discuss the pathophysiological mechanisms involved in abnormal ventilatory response to exercise, with an emphasis on both patients with heart failure syndrome and coronary artery disease. Secondly, special focus was dedicated to the role of aerobic exercise training in improving indices of ventilatory efficiency among these patients, as well as to the underlying mechanisms involved.
Subject(s)
Humans , Male , Female , Coronary Artery Disease/physiopathology , Exercise/physiology , Heart Failure/physiopathology , Pulmonary Ventilation/physiology , Coronary Artery Disease/rehabilitation , Exercise Test , Exercise Therapy/methods , Heart Failure/rehabilitation , Oxygen Consumption/physiology , Pulmonary Gas Exchange/physiology , Time FactorsABSTRACT
The oxygen uptake efficiency slope (OUES) is a submaximal index incorporating cardiovascular, peripheral, and pulmonary factors that determine the ventilatory response to exercise. The purpose of this study was to evaluate the effects of continuous exercise training and interval exercise training on the OUES in patients with coronary artery disease. Thirty-five patients (59.3±1.8 years old; 28 men, 7 women) with coronary artery disease were randomly divided into two groups: continuous exercise training (n=18) and interval exercise training (n=17). All patients performed graded exercise tests with respiratory gas analysis before and 3 months after the exercise-training program to determine ventilatory anaerobic threshold (VAT), respiratory compensation point, and peak oxygen consumption (peak VO2). The OUES was assessed based on data from the second minute of exercise until exhaustion by calculating the slope of the linear relation between oxygen uptake and the logarithm of total ventilation. After the interventions, both groups showed increased aerobic fitness (P<0.05). In addition, both the continuous exercise and interval exercise training groups demonstrated an increase in OUES (P<0.05). Significant associations were observed in both groups: 1) continuous exercise training (OUES and peak VO2 r=0.57; OUES and VO2 VAT r=0.57); 2) interval exercise training (OUES and peak VO2 r=0.80; OUES and VO2 VAT r=0.67). Continuous and interval exercise training resulted in a similar increase in OUES among patients with coronary artery disease. These findings suggest that improvements in OUES among CAD patients after aerobic exercise training may be dependent on peripheral and central mechanisms.
Subject(s)
Humans , Male , Female , Middle Aged , Oxygen Consumption/physiology , Coronary Artery Disease/metabolism , Exercise/physiology , Exercise Therapy/methods , Coronary Artery Disease/physiopathology , Coronary Artery Disease/rehabilitation , Anaerobic Threshold/physiology , Program Evaluation/statistics & numerical data , Body Mass Index , Analysis of Variance , Ventricular Function, Left , Exercise Test/methods , Physical Exertion/physiology , Physical Conditioning, Human/methods , Hypertension/physiopathologyABSTRACT
PURPOSE: The aim of this study was to provide a comprehensive evaluation of the pattern and timing of breathing during incremental exercise in a sample of women living with systemic lupus erythematosus (SLE). METHODS: In this cross-sectional study, 20 women with SLE without pulmonary involvement were compared with 20 gender-, body mass index- (BMI), and age-matched healthy individuals. By using a cardiopulmonary incremental exercise test, the following parameters were assessed: tidal volume (VT); breathing frequency (BF); total respiratory time (TOT); inspiratory time (TI); expiratory time (TE); inspiratory time to total time (TI/TOT); mean inspiratory flow (VT/TI); ventilatory equivalent for carbon dioxide (VE/VCO2) and end-tidal carbon dioxide pressure (PETCO2). RESULTS: BF and BF/VT were significantly higher in patients with SLE versus controls, whereas VT, TE, TI and TOT were significantly lower in the former group ( p<0.05). Additionally, patients with SLE presented higher VE/VCO2 and lower PETCO2 than controls ( p<0.05), suggesting a ventilatory inefficiency. CONCLUSION: We reported compelling evidence of abnormal pattern and timing of breathing during incremental exercise in SLE. Considering that an erratic control of breathing may play an important role in exercise intolerance and fatigue, respiratory exercises emerge as a potential treatment for these symptoms in patients with SLE.