Qualitative dimensions of exertional dyspnea in fibrotic interstitial lung disease.

Unsatisfied inspiration is commonly reported during exercise by patients with interstitial lung disease (ILD). However, the physiological basis of perceived dyspnea quality in this population has not been evaluated. We examined the relationship between dyspnea quality and indices of ventilatory-mechanical limitations during exercise in patients with fibrotic ILD.

Neurophysiological mechanisms of exertional dyspnoea in fibrotic interstitial lung disease.

Our understanding of the mechanisms of dyspnoea in fibrotic interstitial lung disease (ILD) is incomplete. The aims of this study were two-fold: 1) to determine whether dyspnoea intensity is better predicted by neural respiratory drive (NRD) or neuromechanical uncoupling (NMU) of the respiratory system in fibrotic ILD, and 2) to examine the effect of breathing 60% oxygen on NRD, NMU and dyspnoea ratings.Fourteen patients with fibrotic ILD were included.

Sex differences in respiratory muscle activation patterns during high-intensity exercise in healthy humans.

Although women experience greater ventilatory constraints and have a higher work of breathing during exercise, they are less susceptible to diaphragm fatigue compared to men. The mechanisms for diaphragmatic fatigue resistance in women is unknown but may be related to sex differences in respiratory muscle recruitment. Accordingly, the purpose of this study was to determine if electromyography (EMG) of the diaphragm (EMGdi) and extra-diaphragmatic inspiratory muscles differ between sexes during exercise.

Effects of inspiratory muscle training on respiratory muscle electromyography and dyspnea during exercise in healthy men.

Inspiratory muscle training (IMT) has consistently been shown to reduce exertional dyspnea in health and disease; however, the physiological mechanisms remain poorly understood. A growing body of literature suggests that dyspnea intensity can be explained largely by an awareness of increased neural respiratory drive, as measured indirectly using diaphragmatic electromyography (EMGdi). Accordingly, we sought to determine whether improvements in dyspnea following IMT can be explained by decreases in inspiratory muscle electromyography (EMG) activity.

Qualitative dimensions of exertional dyspnea in adults with cystic fibrosis.

No studies of cystic fibrosis (CF) have systematically characterized the evolution of the qualitative dimensions of exertional dyspnea. Adults with CF (n = 25) and control individuals matched for sex, age, and body mass index (n = 25) underwent cardiopulmonary cycle exercise testing with a detailed evaluation of ventilatory and dyspnea responses. The qualitative dimensions of dyspnea were examined during each exercise stage by having subjects select phrases that best described their breathing (i.

Cardiorespiratory and sensory responses to exercise in adults with mild cystic fibrosis.

The purpose of this study was to evaluate cardiorespiratory fitness and reasons for exercise curtailment in a contemporary adult cystic fibrosis (CF) cohort with mild lung disease. Adults with mild CF (n = 19, forced expiratory volume in 1 s = 95 ± 17% predicted) were age-, sex-, ethnicity-, and body mass index-matched to healthy controls (n = 19) and underwent a detailed cardiopulmonary cycle exercise test. While CF subjects had a reduced peak oxygen uptake compared with controls, the values were normal when expressed as %predicted in 14/19 (74%) of subjects.

Sex differences in the intensity and qualitative dimensions of exertional dyspnea in physically active young adults.

Understanding sex differences in the qualitative dimensions of exertional dyspnea may provide insight into why women are more affected by this symptom than men. This study explored the evolution of the qualitative dimensions of dyspnea in 70 healthy, young, physically active adults (35 M and 35 F). Participants rated the intensity of their breathing discomfort (Borg 0-10 scale) and selected phrases that best described their breathing from a standardized list (work/effort, unsatisfied inspiration, and unsatisfied expiration) throughout each stage of a symptom-limited incremental-cycle exercise test.

Physiological mechanisms of dyspnea relief following ivacaftor in cystic fibrosis: a case report.

Ivacaftor is a novel oral pharmacologic agent that specifically targets the genetic defect of cystic fibrosis (CF) by augmenting chloride conductance through the CF transmembrane regulator (CFTR) protein. For individuals with CF and at least one copy of the G551D gating mutation, improvements in sweat chloride, nutritional parameters, lung function, respiratory symptoms, and exercise tolerance (i.e.

Heliox breathing equally influences respiratory mechanics and cycling performance in trained males and females.

In this study we tested the hypothesis that inspiring a low-density gas mixture (helium-oxygen; HeO2) would minimize mechanical ventilatory constraints and preferentially increase exercise performance in females relative to males. Trained male (n = 11, 31 yr) and female (n = 10, 26 yr) cyclists performed an incremental cycle test to exhaustion to determine maximal aerobic capacity (V̇o2max; male = 61, female = 56 ml·kg(-1)·min(-1)). A randomized, single-blinded crossover design was used for two experimental days where subjects completed a 5-km cycling time trial breathing humidified compressed room air or HeO2 (21% O2:balance He).

Cardiorespiratory and sensory responses to exercise in well-controlled asthmatics.

Objectives: The purpose of this study was to evaluate detailed ventilatory, cardiovascular and sensory responses to cycle exercise in sedentary patients with well-controlled asthma and healthy controls.

Methods: Subjects included sedentary patients meeting criteria for well-controlled asthma (n = 14), and healthy age- and activity-matched controls (n = 14). Visit 1 included screening for eligibility, medical history, anthropometrics, physical activity assessment, and pre- and post-bronchodilator spirometry.

Effects of an aging pulmonary system on expiratory flow limitation and dyspnoea during exercise in healthy women.

Aging related changes in pulmonary function may make older women (OW) more susceptible to expiratory flow limitation (EFL) and lead to higher dyspnoea ratings during exercise relative to young women (YW). Accordingly, the purpose of this study was to compare sensory responses and EFL susceptibility and magnitude in 8 YW (29 ± 7 years) and 8 healthy OW (64 ± 3 years) matched for percentage-predicted forced vital capacity (% predicted FVC) and % predicted forced expiratory volume in 1 s. EFL was calculated as the percent overlap between tidal flow-volume loops during maximal exercise and the maximal expiratory flow-volume (MEFV) curve.

Determinants of expiratory flow limitation in healthy women during exercise.

Purpose: Expiratory flow limitation (EFL) can occur in healthy young women during exercise. We questioned whether the occurrence and severity of EFL were related to aerobic fitness or anatomical factors.

Methods: Twenty-two healthy young (<40 yr) women performed a progressive cycle test to exhaustion.