Sex differences in exercise-induced arterial hypoxemia and pulmonary edema following high-intensity exercise in highly trained endurance athletes.

This study investigated sex differences in the development of pulmonary edema and exercise-induced arterial hypoxemia (EIAH) in well-trained endurance athletes during near-maximal exercise in a real-world setting. Twenty participants (10M vs. 10F; V̇Opeak: 69.

Multidimensional assessment of exertional dyspnea in young healthy males and females who select unsatisfied inspiration at peak exercise.

Historically, it was thought that healthy humans predominantly described their breathing as a sense of increased work or effort (W/E) during maximal exercise. However, emerging data show that many healthy adults select unpleasant dyspnea descriptors such as "unsatisfied inspiration" (UI), with relatively more females selecting UI than males. We hypothesized that males and females who select UI would report higher dyspnea intensity ratings during exercise, select more distressing dyspnea qualities post exercise, and have greater inspiratory constraints than those who do not.

Voluntary activation of the diaphragm after inspiratory pressure threshold loading.

After a bout of isolated inspiratory work, such as inspiratory pressure threshold loading (IPTL), the human diaphragm can exhibit a reversible loss in contractile function, as evidenced by a decrease in transdiaphragmatic twitch pressure (P ). Whether or not diaphragm fatigability after IPTL is affected by neural mechanisms, measured through voluntary activation of the diaphragm (D-VA) in addition to contractile mechanisms, is unknown. It is also unknown if changes in D-VA are similar between sexes given observed differences in diaphragm fatigability between males and females.

Effects of Face Masks on the Multiple Dimensions and Neurophysiological Mechanisms of Exertional Dyspnea.

Introduction: During the coronavirus disease 2019 pandemic, public health officials widely adopted the use of face masks (FM) to minimize infections. Despite consistent evidence that FMs increase dyspnea, no studies have examined the multidimensional components of dyspnea or their underlying physiological mechanisms.

Methods: In a randomized crossover design, 16 healthy individuals ( n = 9 women, 25 ± 3 yr) completed incremental cycling tests over three visits, where visits 2 and 3 were randomized to either surgical FM or no mask control.

Sex Differences in Diaphragm Voluntary Activation after Exercise.

Introduction: The female diaphragm develops less fatigue after high-intensity exercise compared with males. Diaphragm fatigability is typically defined as a decrease in transdiaphragmatic twitch pressure (Pdi,TW) and represents the contractile function of the muscle. However, it is unclear whether this sex difference persists when examining changes in voluntary activation, which represents a neural mechanism contributing to fatigability.

Case Studies in Physiology: Cardiopulmonary exercise testing and inspiratory muscle training in a 59-year-old, 4 years after an extrapleural pneumonectomy.

This case report characterizes the physiological responses to incremental cycling and determines the effects of 12 wk of inspiratory muscle training (IMT) on respiratory muscle strength, exercise capacity, and dyspnea in a physically active 59-yr-old female, 4 years after a left-sided extrapleural pneumonectomy (EPP). On separate days, a symptom-limited incremental exercise test and a constant work rate (CWR) test at 75% of peak work rate (WR) were completed, followed by 12 wk of IMT and another CWR test. IMT consisted of two sessions of 30 repetitions twice daily for 5 days per week.

Effects of the Elevation Training Mask® 2.0 on dyspnea and respiratory muscle mechanics, electromyography, and fatigue during exhaustive cycling in healthy humans.

Objectives: Examine the effects of the Elevation Training Mask® 2.0 (ETM) on dyspnea, and respiratory muscle function and fatigue during exercise.

Design: Randomized crossover.

Reliability of diaphragm voluntary activation measurements in healthy adults.

Voluntary activation can be used to assess central fatigue of the diaphragm after tasks such as exercise or inspiratory muscle loading. Cervical magnetic stimulation (CMS) of the phrenic nerves elicits an involuntary contraction, or twitch, of the diaphragm. This twitch is quantified based on a measure of transdiaphragmatic pressure and can be used to evaluate diaphragm contractile function and diaphragm voluntary activation (diaphragm-VA).

A multidimensional assessment of dyspnoea in healthy adults during exercise.

Purpose: (1) To determine whether healthy humans can distinguish between the intensity and unpleasantness of exertional dyspnoea; (2) to evaluate the reliability of qualitative dyspnoea descriptors during exercise; and (3) to assess the reliability of the Multidimensional Dyspnoea Profile (MDP) METHODS: Forty-four healthy participants (24M:20F, 25 ± 5 years) completed maximal incremental cycling tests on three visits. During visit 1, participants rated the intensity and unpleasantness of dyspnoea simultaneously throughout exercise using the modified 0-10 category-ratio Borg scale. On visits 2 and 3, participants rated either the intensity or unpleasantness of dyspnoea alone at the same measurement times as visit 1.

Effects of the Turbine™ on Ventilatory and Sensory Responses to Incremental Cycling.

Introduction: The Turbine™ is a nasal dilator marketed to athletes to increase airflow, which may serve to reduce dyspnea and improve exercise performance, presumably via reductions in the work of breathing (WOB). However, the unpublished data supporting these claims were collected in individuals at rest that were exclusively nasal breathing. These data are not indicative of how the device influences breathing during exercise at higher ventilations when a larger proportion of breathing is through the mouth.

Short-term effects of Lumacaftor/Ivacaftor (Orkambi™) on exertional symptoms, exercise performance, and ventilatory responses in adults with cystic fibrosis.

Rationale: Lumacaftor/ivacaftor (LUM/IVA) modestly improves lung function following 1 month of treatment but it is unknown if this translates into improvements in exercise endurance and exertional symptoms.

Methods: Adult CF participants completed a symptom-limited constant load cycling test with simultaneous assessments of dyspnea and leg discomfort ratings pre- and 1 month post-initiation of LUM/IVA.

Results: Endurance time, exertional dyspnea and leg discomfort ratings at submaximal exercise did not change significantly.

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.

The Impact of Cycling Cadence on Respiratory and Hemodynamic Responses to Exercise.

Purpose: The physiological consequences of freely chosen cadence during cycling remains poorly understood. We sought to determine the effect of cadence on the respiratory and hemodynamic response to cycling exercise.

Methods: Eleven cyclists (10 males, 1 female; age, 27 ± 6 yr; V˙O2max = 60.

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 respiratory muscle work on respiratory and locomotor blood flow during exercise.

What is the central question of this study? Does manipulation of the work of breathing during high-intensity exercise alter respiratory and locomotor muscle blood flow? What is the main finding and its importance? We found that when the work of breathing was reduced during exercise, respiratory muscle blood flow decreased, while locomotor muscle blood flow increased. Conversely, when the work of breathing was increased, respiratory muscle blood flow increased, while locomotor muscle blood flow decreased. Our findings support the theory of a competitive relationship between locomotor and respiratory muscles during intense exercise.

Respiratory Mechanical and Cardiorespiratory Consequences of Cycling with Aerobars.

Purpose: Aerobars place a cyclist in a position where the trunk is flexed forward and the elbows are close to the midline of the body. This position is known to improve cycling aerodynamics and time trial race performance compared with upright cycling positions. However, the aggressive nature of this position may have important cardiorespiratory and metabolic consequences.

Is parasternal intercostal EMG an accurate surrogate of respiratory neural drive and biomarker of dyspnea during cycle exercise testing?

Recent evidence suggests that surface electromyography of the parasternal intercostals (EMGpara) can be a non-invasive alternative to diaphragmatic EMG (EMGdi) for estimating neural respiratory drive (NRD) during cardiopulmonary exercise testing (CPET). The purpose of this study was to determine if non-respiratory muscles influence EMGpara by having subjects place their hands on (H) and off (H) the handlebars during cycling-based CPET. Ten healthy adults performed an incremental cycling test until volitional exhaustion.