Pulmonary gas exchange in relation to exercise pulmonary hypertension in patients with heart failure with preserved ejection fraction.

Background: Exercise pulmonary hypertension (ePH), defined as a mean pulmonary artery pressure (mPAP)/cardiac output (Qc) slope >3 WU during exercise, is common in patients with heart failure with preserved ejection fraction (HFpEF). However, the pulmonary gas exchange-related effects of an exaggerated ePH (EePH) response are not well-defined, especially in relation to dyspnea on exertion (DOE) and exercise intolerance.

Methods: 48 HFpEF patients underwent invasive (pulmonary and radial artery catheters) constant-load (20W) and maximal incremental cycle testing.

Identifying the Mechanisms of a Peripherally Limited Exercise Phenotype in Patients With Heart Failure With Preserved Ejection Fraction.

Background: We identified peripherally limited patients using cardiopulmonary exercise testing and measured skeletal muscle oxygen transport and utilization during invasive single leg exercise testing to identify the mechanisms of the peripheral limitation.

Methods: Forty-five patients with heart failure with preserved ejection fraction (70±7 years, 27 females) completed seated upright cardiopulmonary exercise testing and were defined as having a (1) peripheral limitation to exercise if cardiac output/oxygen consumption (VO) was elevated (≥6) or 5 to 6 with a stroke volume reserve >50% (n=31) or (2) a central limitation to exercise if cardiac output/VO slope was ≤5 or 5 to 6 with stroke volume reserve <50% (n=14). Single leg knee extension exercise was used to quantify peak leg blood flow (Doppler ultrasound), arterial-to-venous oxygen content difference (femoral venous catheter), leg VO, and muscle oxygen diffusive conductance.

Ventilatory Responses to Exercise by Age, Sex, and Health Status.

An understanding of the normal pulmonary responses to incremental exercise is requisite for appropriate interpretation of findings from clinical exercise testing. The purpose of this review is to provide concrete information to aid the interpretation of the exercise ventilatory response in both healthy and diseased populations. We begin with an overview of the normal exercise ventilatory response to incremental exercise in the healthy, normally trained young-to-middle aged adult male.

Pediatric patients diagnosed as overweight and obese have an elevated risk of dyspnea.

We investigated whether pediatric patients with overweight and obesity are more likely to have dyspnea compared with those who are non-overweight. We collected de-identified data from TriNetX, a global federated multicenter research database, using both the UT Southwestern Medical Center and multinational Research Networks. Our analysis focused on patients aged 8-12 years.

Static respiratory mechanics are unaltered in males and females with obesity.

We tested the hypothesis that independent of the obesity-related shift in lung volume subdivisions, obesity would not reduce the interrelationships of expiratory flow, lung volume, and static lung elastic recoil pressure in males and females. Simultaneous measurements of expiratory flow, volume, and transpulmonary pressure were continuously recorded while flow-volume loops of varying expiratory efforts were performed in a pressure-corrected, volume-displacement body plethysmograph in males and females with obesity. Static compliance curves were collected using the occlusion technique.

Ventilatory limitations in patients with HFpEF and obesity.

Heart failure with preserved ejection fraction (HFpEF) patients have an increased ventilatory demand. Whether their ventilatory capacity can meet this increased demand is unknown, especially in those with obesity. Body composition (DXA) and pulmonary function were measured in 20 patients with HFpEF (69 ± 6 yr;9 M/11 W).

Elevated risk of dyspnea in adults with obesity.

We investigated whether older adults (OA) with obesity are more likely to have dyspnea compared with OA without obesity, and whether OA with obesity are at a greater risk of having dyspnea compared with middle-aged (MA) and younger adults (YA) with obesity. We obtained de-identified data from the TriNetX UT Southwestern Medical Center database. We identified obesity and dyspnea using ICD-10-CM codes E66 and R06.

Reducing Pulmonary Capillary Wedge Pressure During Exercise Exacerbates Exertional Dyspnea in Patients With Heart Failure With Preserved Ejection Fraction: Implications for V˙/Q˙ Mismatch.

Background: The primary cause of dyspnea on exertion in heart failure with preserved ejection fraction (HFpEF) is presumed to be the marked rise in pulmonary capillary wedge pressure during exercise; however, this hypothesis has never been tested directly. Therefore, we evaluated invasive exercise hemodynamics and dyspnea on exertion in patients with HFpEF before and after acute nitroglycerin (NTG) treatment to lower pulmonary capillary wedge pressure.

Research Question: Does reducing pulmonary capillary wedge pressure during exercise with NTG improve dyspnea on exertion in HFpEF?

Study Design And Methods: Thirty patients with HFpEF performed two invasive 6-min constant-load cycling tests (20 W): one with placebo (PLC) and one with NTG.

Inhibiting regional sweat evaporation modifies the ventilatory response to exercise: interactions between core and skin temperature.

In humans, elevated body temperatures can markedly increase the ventilatory response to exercise. However, the impact of changing the effective body surface area (BSA) for sweat evaporation (BSA) on such responses is unclear. Ten healthy adults (9 males, 1 female) performed eight exercise trials cycling at 6 W/kg of metabolic heat production for 60 min.

Six Months of Exercise Training Improves Ventilatory Responses during Exercise in Adults with Well-Healed Burn Injuries.

Introduction: Pulmonary function is lower after a severe burn injury, which could influence ventilatory responses during exercise. It is unclear whether exercise training improves pulmonary function or ventilatory responses during exercise in adults with well-healed burn injuries. Therefore, we tested the hypothesis that exercise training improves pulmonary function and ventilatory responses during exercise in adults with well-healed burn injuries.

Challenging the Hemodynamic Hypothesis in Heart Failure With Preserved Ejection Fraction: Is Exercise Capacity Limited by Elevated Pulmonary Capillary Wedge Pressure?

Background: Exercise intolerance is a defining characteristic of heart failure with preserved ejection fraction (HFpEF). A marked rise in pulmonary capillary wedge pressure (PCWP) during exertion is pathognomonic for HFpEF and is thought to be a key cause of exercise intolerance. If true, acutely lowering PCWP should improve exercise capacity.

Sex differences in the ventilatory responses to exercise in mild to moderate obesity.

New Findings: What is the central question of the study? What are the sex differences in ventilatory responses during exercise in adults with obesity? What is the main finding and its importance? Tidal volume and expiratory flows are lower in females when compared with males at higher levels of ventilation despite small increases in end-expiratory lung volumes. Since dyspnoea on exertion is a frequent complaint, particularly in females with obesity, careful attention should be paid to unpleasant respiratory symptoms and mechanical ventilatory constraints while prescribing exercise.

Abstract: Obesity is associated with altered ventilatory responses, which may be exacerbated in females due to the functional consequences of sex-related morphological differences in the respiratory system.

Alveolar Dead Space Is Augmented During Exercise in Patients With Heart Failure With Preserved Ejection Fraction.

Background: Patients with heart failure with preserved ejection fraction (HFpEF) exhibit many cardiopulmonary abnormalities that could result in V˙/Q˙ mismatch, manifesting as an increase in alveolar dead space (VD) during exercise. Therefore, we tested the hypothesis that VD would increase during exercise to a greater extent in patients with HFpEF compared with control participants.

Research Question: Do patients with HFpEF develop VD during exercise?

Study Design And Methods: Twenty-three patients with HFpEF and 12 control participants were studied.

Adults with well-healed burn injuries have lower pulmonary function values decades after injury.

Sub-acute (e.g., inhalation injury) and/or acute insults sustained during a severe burn injury impairs pulmonary function.

Physiological dead space during exercise in patients with heart failure with preserved ejection fraction.

Heart failure with preserved ejection fraction (HFpEF) is associated with cardiopulmonary abnormalities that may increase physiological dead space to tidal volume (VD/VT) during exercise. However, studies have not corrected VD/VT for apparatus mechanical dead space (VDM), which may confound the accurate calculation of VD/VT. We evaluated whether calculating physiological dead space with (VD/VT) and without (VD/VT) correcting for VDM impacts the interpretation of gas exchange efficiency during exercise in HFpEF.

Repeatability of dyspnea measurements during exercise in women with obesity.

While the 0-10 Borg scale to rate perceived breathlessness (RPB) is widely used to assess dyspnea on exertion, the repeatability of RPB in women with obesity is unknown. We examined the repeatability of RPB in women with obesity during submaximal constant-load cycling following at least 10 weeks of normal daily life. Seventeen women (37 ± 7 yr; 34.

Estimating exercise Pa in patients with heart failure with preserved ejection fraction.

Patients with heart failure with preserved ejection fraction (HFpEF) exhibit cardiopulmonary abnormalities that could affect the predictability of exercise [Formula: see text] from the Jones corrected partial pressure of end-tidal CO (PJ) equation (PJ = 5.5 + 0.9 × [Formula: see text] - 2.

Dysanapsis in men and women with obesity.

Obesity alters chest wall mechanics, reduces lung volumes, and increases airway resistance. In addition, the luminal area of the larger conducting airways is smaller in women than in men when matched for lung size. We examined whether differences in pulmonary mechanics with obesity and sex were associated with the dysanapsis ratio (DR), an estimate of airway size when the expiratory flow is maximal, in men and women with and without obesity.

Dyspnea during exercise and voluntary hyperpnea in women with obesity.

Temporal responses of ratings of perceived breathlessness (RBP) during constant-load and incremental exercise, and during voluntary hyperpnea (EVH) were examined in women with obesity. Following 6 min of constant-load (60W) cycling, 34 women rated RPB≥4 (+DOE) and 22 women rated RPB≤2 (-DOE). Both groups completed an incremental cycling test and an EVH test at 40 and 60L/min; RPB was assessed each minute of incremental cycling and at the end of each EVH trial.

Obesity Blunts the Ventilatory Response to Exercise in Men and Women.

Obesity presents a mechanical load to the thorax, which could perturb the generation of minute ventilation (V̇e) during exercise. Because the respiratory effects of obesity are not homogenous among all individuals with obesity and obesity-related effects could vary depending on the magnitude of obesity, we hypothesized that the exercise ventilatory response (slope of the V̇e and carbon dioxide elimination [V̇co] relationship) would manifest itself differently as the magnitude of obesity increases. To investigate the V̇e/V̇co slope in an obese population that spanned across a wide body mass index (BMI) range.

Inhaled albuterol increases estimated ventilatory capacity in nonasthmatic children without and with obesity.

Forced mid-expiratory flow (i.e., isoFEF) may increase with a short-acting β-agonist in nonasthmatic children without bronchodilator responsiveness.

Cardiac perturbations after high-intensity exercise are attenuated in middle-aged compared with young endurance athletes: diminished stress or depleted stimuli?

Strenuous exercise elicits transient functional and biochemical cardiac imbalances. Yet, the extent to which these responses are altered owing to aging is unclear. Accordingly, echocardiograph-derived left ventricular (LV) and right ventricular (RV) global longitudinal strain (GLS) and high-sensitivity cardiac troponin I (hs-cTnI) were assessed before (pre) and after (post) a 60-min high-intensity cycling race intervention (CRIT) in 11 young (18-30 yr) and 11 middle-aged (40-65 yr) highly trained male cyclists, matched for cardiorespiratory fitness.

External dead space explains sex-differences in the ventilatory response to submaximal exercise in children with and without obesity.

We compared the exercise ventilatory response (slope of the ventilation, V̇ and carbon dioxide production, V̇CO relationship) in boys and girls with and without obesity. 46 children with obesity (BMI percentile: 97.7 ± 1.