End-expiratory lung volume during arm and leg exercise in normal subjects and patients with cystic fibrosis

The effect of age and sex on peak oxygen uptake during upper and lower body exercise: A systematic review

BACKGROUND

Large scale population norms for peak oxygen uptake (VO2peak) during cycle ergometry (CE) have been published for men and women across a wide range of ages. Although upper body functional capacity has an important role in activities of daily living far less is known regarding the effect of age and sex on upper body functional capacity (i.e. arm crank ergometry; ACE). The aim of this review was to determine the effect of age and sex on VO2peak obtained during ACE and CE in the same participants.

METHOD

The review was pre-registered with PROSEPERO (Ref: CRD42022349566). A database search using Academic Search Complete including CINAHL complete, CINHAL Ultimate, Medline, PubMed, SPORTDiscus was undertaken.

RESULTS

The initial search yielded 460 articles which was reduced to 243 articles following removal of duplicates. Twenty-five articles were subsequently excluded based on title resulting in 218 articles considered for retrieval. Following review of the abstracts, 78 further articles were excluded leaving 140 to be assessed for eligibility. Eighty-five articles were subsequently excluded, resulting in 55 articles being included. The decrease in VO2peak with age during CE was consistent with previous studies. Decreases in VO2peak during ACE with age, although paralleling those of CE, appeared to be of greater functional importance. When changes in VO2peak were considered below the age of 50 years little change was observed for absolute VO2peak during ACE and CE. In contrast, relative VO2peak demonstrated decreases in VO2peak for both ACE and CE likely reflecting increases in body mass and body fat percentage with age. After 50 years of age absolute and relative VO2peak demonstrated more similar and subtle responses. Heterogeneity across studies for both absolute and relative VO2peak between ACE and CE was large. Although strict inclusion criteria were applied, the inter-individual variation in sample populations was likely the main source of heterogeneity. There was a considerable lack data sets available for ages above 40 years of age.

CONCLUSIONS

These responses suggest that upper body VO2peak decreases in line with that of the lower body but, due to the lower peak values achieved during ACE, decreases in VO2peak may have more profound functional impact compared to that for the lower body. Using absolute and relative measures of VO2peak results in different age-related profiles when considered below 50 years of age. To further our understanding of whole body ageing more data is required for participants in mid and later life. The association between VO2peak and underlying physiological factors with age needs to be studied further, particularly in conjunction with activities of daily living and independent living.

Mechanisms of ventilatory limitation to maximum exercise in children and adolescents with chronic airway diseases

INTRODUCTION

Exercise intolerance is common in chronic airway diseases (CAD), but its mechanisms are still poorly understood. The aim of this study was to evaluate exercise capacity and its association with lung function, ventilatory limitation, and ventilatory efficiency in children and adolescents with cystic fibrosis (CF) and asthma when compared to healthy controls.

METHODS

Cross-sectional study including patients with mild-to-moderate asthma, CF and healthy children and adolescents. Anthropometric data, lung function (spirometry) and exercise capacity (cardiopulmonary exercise testing) were evaluated. Primary outcomes were peak oxygen consumption (VO2 peak), forced expiratory volume in 1 s (FEV1 ), breathing reserve (BR), ventilatory equivalent for oxygen consumption (VE /VO2 ) and for carbon dioxide production (VE /VCO2 ), both at the ventilatory threshold (VT1 ) and peak exercise.

RESULTS

Mean age of 147 patients included was 11.8 ± 3.0 years. There were differences between asthmatics and CF children when compared to their healthy peers for anthropometric and lung function measurements. Asthmatics showed lower VO2 peak when compared to both healthy and CF subjects, although no differences were found between healthy and CF patients. A lower BR was found when CF patients were compared to both healthy and asthmatic. Both CF and asthmatic patients presented higher values for VE /VO2 and VE /VCO2 at VT1 when compared to healthy individuals. For both VE /VO2 and VE /VCO2 at peak exercise CF patients presented higher values when compared to their healthy peers.

CONCLUSION

Patients with CF achieved good exercise capacity despite low ventilatory efficiency, low BR, and reduced lung function. However, asthmatics reported reduced cardiorespiratory capacity and normal ventilatory efficiency at peak exercise. These results demonstrate differences in the mechanisms of ventilatory limitation to maximum exercise testing in children and adolescents with CAD.

Identifying the Optimal Arm Priming Exercise Intensity to Improve Maximal Leg Sprint Cycling Performance

Priming exercises improve subsequent motor performance; however, their effectiveness may depend on the workload and involved body areas. The present study aimed to estimate the effects of leg and arm priming exercises performed at different intensities on maximal sprint cycling performance. Fourteen competitive male speed-skaters visited a lab eight times, where they underwent a body composition measurement, two V̇O_2max measurements (leg and arm ergometers), and five sprint cycling sessions after different priming exercise conditions. The five priming exercise conditions included 10-minute rest (Control); 10-minute arm ergometer exercise at 20% V̇O_2max (Arm 20%); 10-minute arm ergometer exercise at 70% V̇O_2max (Arm 70%); 1-min maximal arm ergometer exercise at 140% V̇O_2max (Arm 140%); and 10-min leg ergometer exercise at 70% V̇O_2max (Leg 70%). Power outputs of 60-s maximal sprint cycling, blood lactate concentration, heart rate, muscle and skin surface temperature, and rating of perceived exertion were compared between the priming conditions at different measurement points. Our results showed that the Leg 70% was the optimal priming exercise among our experimental conditions. Priming exercise with the Arm 70% also tended to improve subsequent motor performance, while Arm 20% and Arm 140% did not. Mild elevation in blood lactate concentration by arm priming exercise may improve the performance of high-intensity exercise.

Effects of maneuver of hair-washing motion and gender on oxygen uptake and ventilation in healthy people

It is known that patients with chronic obstructive pulmonary disease experience dyspnea during unsupported arm exercise (UAE). We examined the respiratory variables in during a hair-washing motion for healthy young people requiring the UAE to find the effects across gender, motion, and speed. In this study, 33 healthy young people were enrolled. Participants performed the following four types of hair-washing motions: both hands with fast speed, both hands with slow speed, one hand with fast speed, and one hand with slow speed. The respiratory variables such as oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂), carbon dioxide output (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙CO₂), and respiratory rate (RR), or minute ventilation (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙_E) were measured. Regarding \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙CO₂, and RR during the rest period and in each motion, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂ and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙CO₂ in males were significantly greater than those in females. RR in the female participants had greater value than that in males. Among the maneuvers, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙CO₂ or \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙_E during a hair-washing motion with both hands were greater than those during hair-washing motion with one hand. \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙CO₂, RR, or \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙_E during a hair-washing motion with both hands fast speed was greater than those during a hair-washing motion with slow speed. In conclusion, this study showed the effects owing to the differences in motion maneuvers and gender during UAE in healthy young people. These suggest a need to consider motion maneuver or gender when teaching motion methods of activities of daily living on the patients.

Reduced exercise ventilatory efficiency in adults with cystic fibrosis and normal to moderately impaired lung function

Despite being a hallmark and an independent prognostic factor in several cardiopulmonary diseases, ventilatory efficiency-i.e., minute ventilation/carbon dioxide output relationship (V̇e/V̇co₂)-has never been systematically explored in cystic fibrosis (CF). To provide a comprehensive frame of reference regarding measures of ventilatory efficiency in CF adults with normal to moderately impaired lung function and to confirm the hypothesis that V̇e/V̇co₂ is a sensitive marker of early lung disease. CF patients were divided into three groups, according to their spirometry: normal (G₁), mild impairment (G₂), and moderate impairment (G₃) in lung function. All participants underwent incremental cardiopulmonary exercise testing on a cycle ergometer. Lowest V̇e/V̇co₂ ratio (nadir) and the slope and the intercept of the linear region of the V̇e/V̇co₂ relationship were contrasted in a two-center retrospective analysis, involving 72 CF patients and 36 healthy controls (HC). Compared with HC, CF patients had significantly higher V̇e/V̇co₂ nadir, slope, and intercept (P < 0.001, P < 0.001, and P = 0.049, respectively). Subgroup analysis revealed significant differences in nadir (P = 0.001) and slope (P = 0.012) values even between HC and G₁. Dynamic hyperinflation related negatively with slope (P = 0.045) and positively with intercept (P = 0.001), while no impact on nadir was observed. Ventilatory inefficiency is a clear feature of adults with CF, even among patients with normal spirometry. V̇e/V̇co₂ nadir seems to be the most reliable metric to describe ventilatory efficiency in CF adults. Further prospective studies are needed to clarify whether V̇e/V̇co₂ could represent a useful marker in the evaluation of early lung disease in CF.NEW & NOTEWORTHY This is the first study to investigate ventilatory efficiency in a cohort of adult cystic fibrosis (CF) patients with nonsevere lung disease. The finding of impaired ventilatory efficiency in patients with normal lung function confirms the higher sensitivity of exercise testing in detecting early lung disease compared with spirometry. Dynamic hyperinflation plays a significant role in determining the behavior of V̇e/V̇co₂ slope and intercept values with increasing lung function impairment. Apparently free from interference from mechanical constraints, V̇e/V̇co₂ nadir seems the most reliable parameter to evaluate ventilatory efficiency in CF adults.

Mechanical-ventilatory responses to peak and ventilation-matched upper- versus lower-body exercise in normal subjects

New Findings

What is the central question of this study?

To what extent are the mechanical‐ventilatory responses to upper‐body exercise influenced by task‐specific locomotor mechanics?

What is the main finding and its importance?

When compared with lower‐body exercise performed at similar ventilations, upper‐body exercise was characterized by tidal volume constraint, dynamic lung hyperinflation and an increased propensity towards neuromechanical uncoupling of the respiratory system. Importantly, these responses were independent of respiratory dysfunction and flow limitation. Thus, the mechanical ventilatory responses to upper‐body exercise are attributable, in part, to task‐specific locomotor mechanics (i.e. non‐respiratory loading of the thorax).

Abstract

The aim of this study was to determine the extent to which the mechanical ventilatory responses to upper‐body exercise are influenced by task‐specific locomotor mechanics. Eight healthy men (mean ± SD: age, 24 ± 5 years; mass, 74 ± 11 kg; and stature, 1.79 ± 0.07 m) completed two maximal exercise tests, on separate days, comprising 4 min stepwise increments of 15 W during upper‐body exercise (arm‐cranking) or 30 W during lower‐body exercise (leg‐cycling). The tests were repeated at work rates calculated to elicit 20, 40, 60, 80 and 100% of the peak ventilation achieved during arm‐cranking (V˙E, UBE ). Exercise measures included pulmonary ventilation and gas exchange, oesophageal pressure‐derived indices of respiratory mechanics, operating lung volumes and expiratory flow limitation. Subjects exhibited normal resting pulmonary function. Arm‐crank exercise elicited significantly lower peak values for work rate, O₂ uptake, CO₂ output, minute ventilation and tidal volume (p < 0.05). At matched ventilations, arm‐crank exercise restricted tidal volume expansion relative to leg‐cycling exercise at 60% V˙E, UBE (1.74 ± 0.61 versus 2.27 ± 0.68 l, p < 0.001), 80% V˙E, UBE (2.07 ± 0.70 versus 2.52 ± 0.67 l, p < 0.001) and 100% V˙E, UBE (1.97 ± 0.85 versus 2.55 ± 0.72 l, p = 0.002). Despite minimal evidence of expiratory flow limitation, expiratory reserve volume was significantly higher during arm‐cranking versus leg‐cycling exercise at 100% V˙E, UBE (39 ± 8 versus 29 ± 8% of vital capacity, p = 0.002). At any given ventilation, arm‐cranking elicited greater inspiratory effort (oesophageal pressure) relative to thoracic displacement (tidal volume). Arm‐cranking exercise is sufficient to provoke respiratory mechanical derangements (restricted tidal volume expansion, dynamic hyperinflation and neuromechanical uncoupling) in subjects with normal pulmonary function and expiratory flow reserve. These responses are likely to be attributable to task‐specific locomotor mechanics (i.e. non‐respiratory loading of the thorax).

Airway clearance physiotherapy improves ventilatory dynamics during exercise in patients with cystic fibrosis: a pilot study

BACKGROUND

Airflow limitation and dynamic hyperinflation may limit exercise capacity in patients with cystic fibrosis (CF). The aim was to investigate whether the undertaking of airway clearance physiotherapy (ACT) prior to cardiopulmonary exercise testing (CPET) results in improvements in exercise capacity.

METHODS

A prospective randomised, cross-over pilot study was performed in children aged >9 years. Spirometry, plethysmography and CPET were performed on two separate occasions-one test with ACT prior to CPET and the other without.

RESULTS

12 patients with CF were included in the study with a mean (SD) age of 12.83 (1.85) years. No significant difference in peak oxygen uptake (VO₂) was found between the tests. However, lower minute ventilation (V_E) and ventilatory equivalents (V_EVO₂ and V_EVCO₂) at ventilatory threshold (VT) were noted when ACT was undertaken prior to CPET. The mean(SD) V_E (L/min) at VT was 26.67 (5.49) vs 28.92 (6.3) (p=0.05), V_EVO₂ (L/min) at VT was 24.5 (1.75) vs 26.05 (2.5) (p=0.03) and V_EVCO₂ (L/min) at VT was 26.58 (2.41) vs 27.98 (2.11) (p=0.03).

CONCLUSIONS

These pilot data suggest that ACT prior to exercise may lead to improved ventilatory dynamics during exercise in individuals with CF.

Is daily physical activity affected by dynamic hyperinflation in adults with cystic fibrosis?

Background

The aim of this study was to investigate the relationship between dynamic hyperinflation and daily physical activity (DPA) in adults with cystic fibrosis (CF).

Methods

Thirty-four clinically stable CF were studied. All patients undertook incremental cardiopulmonary exercise testing (CPET). CPET-related measurements included: oxygen uptake (V’O₂), carbon dioxide production (V’CO₂), ventilatory profile, work rate (W), inspiratory capacity (IC), end-expiratory lung volume (EELV). PA was assessed using the accelerometer SenseWear Pro3 Armband.

Results

Exercise tolerance was reduced in most of patients and the mean V’O_2,peak value was 75.2% of predicted (28.5 ± 4.8 ml/min/kg). Seventy % of patients responded to CPET with dynamic hyperinflation. Higher incidence of dynamic hyperinflation was found in CF males compared to CF females (p = 0.026). Patients who developed dynamic hyperinflation during CPET had higher vigorous PA (p = 0.01) and more total energy expenditure (p = 0.006) than patients who did not. EELVΔ was related to activities requiring vigorous intensity and total energy expenditure (R = 0.46, p = 0.001; R = 0.57, p <  0.001).

Conclusions

In adults with CF and mild to moderate lung impairment, DPA might not be limited by dynamic hyperinflation.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0623-7) contains supplementary material, which is available to authorized users.

Effects of exercise on secretion transport, inflammation, and quality of life in patients with noncystic fibrosis bronchiectasis: Protocol for a randomized controlled trial

BACKGROUND

Bronchiectasis is characterized by pathological and irreversible bronchial dilatation caused by the inefficient mucus and microorganism clearance and progression of inflammatory processes. The most frequent characteristic is the increase in bronchial mucus production resulting in slower transport and damage to the mucociliary transport.

AIMS

To evaluate the effects of exercise on mucus transport, inflammation, and resistance of the respiratory and autonomic nervous systems and subsequent effects on quality of life in patients with bronchiectasis who are enrolled in a pulmonary rehabilitation program.

METHODS

Sixty subjects of both sexes between 18 and 60 years (30 volunteers with clinically stable bronchiectasis and 30 healthy volunteers) will be included. Participants with chronic obstructive pulmonary disease, decompensated cardiovascular or metabolic diseases, neuromuscular and musculoskeletal diseases, and active smokers will be excluded. Volunteers will be randomly allocated to the pulmonary rehabilitation or control groups. The primary outcomes will be nasal transport time as evaluated by nasal saccharin transport time, analysis of nasal lavage, enzyme immunoassay of exhaled expiration, and analysis of the mucus properties. The secondary outcomes will include pulmonary function tests, impulse oscillometry, heart rate variability analysis, and quality of life questionnaires.

DISCUSSION

In addition to the benefits for patients already described in the literature, the additional benefit of mucus removal may contribute to optimizing treatments and better control of the disease.

CONCLUSION

This protocol could provide new information about the unclear mechanisms regarding exercise to aid in the removal of secretions.

Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles

Purpose

Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue.

Methods

Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O₂ uptake [V˙O_2peak] = 31.9 ± 5.3 mL·kg⁻¹·min⁻¹) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O_2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (P_di,tw and P_ga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively.

Results

Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min⁻¹ (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min⁻¹ (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean P_di,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5–15 min) after severe exercise, mean P_ga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H₂O, P < 0.05), with the difference no longer significant after 25–35 min. Abdominal muscle fatigue (defined as ≥15% reduction in P_ga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise.

Conclusions

High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax.

Dynamic hyperinflation in patients with asthma and exercise-induced bronchoconstriction

BACKGROUND

Little is known about the behavior of operative lung volumes during exercise in patients with asthma and exercise-induced bronchoconstriction (EIB).

OBJECTIVE

To compare the presence of dynamic hyperinflation (DH) in patients with mild asthma with and without EIB and in healthy individuals and to relate the changes in end-expiratory lung volume (EELV) with postexercise airflow reduction.

METHODS

A total of 122 consecutive stable patients (>12 years of age) with mild asthma and 38 controls were studied. Baseline lung volumes were measured, and all patients performed an exercise bronchial challenge. At each minute of exercise, EELV and end-inspiratory lung volume (EILV) were estimated from inspiratory capacity measurements to align the tidal breathing flow-volume loops to within the maximal expiratory curve.

RESULTS

DH was more frequent in patients with asthma and EIB (76%) than in patients with asthma but without EIB (11%) or controls (18%). The EELV increased in patients with asthma and EIB and decreased in patients with asthma without EIB and controls during exercise. In the patients with asthma, the decrease in forced expiratory volume in 1 second after the exercise challenge correlated with age (r = -0.179, P = .05), baseline forced vital capacity (r = 0.255, P = .005), EELV increase (r = 0.447, P < .001), and EILV increase (r = 0.246, P = .007). Age, baseline forced vital capacity, and magnitude of DH were retained as independent predictors of EIB intensity.

CONCLUSION

In patients with asthma and EIB, the development of DH is very frequent and related to the intensity of postexercise bronchoconstriction. This finding could implicate DH in the development of EIB.

Ventilatory limitation and dynamic hyperinflation during exercise testing in Cystic Fibrosis

OBJECTIVE

To investigate the presence of dynamic hyperinflation after the Modified Shuttle Test (MST) and its relationship with lung function, exercise tolerance, and clinical symptoms in Cystic Fibrosis (CF).

METHODS

Retrospective observational study. Subjects in clinically stable condition with a CF diagnosis based on a positive sweat test (chloride >60 mEq/L) and/or presence of two disease causing mutations, with available data on MST, spirometry, maximal voluntary ventilation, and inspiratory capacity manoeuvres were considered for the analysis. Breathing reserve was calculated and a threshold value of 0.7 was subsequently chosen as a value of pulmonary mechanical limit. Subjects were then categorized into two groups according to the change in the inspiratory capacity from rest to peak exercise. Unconditional logistic regression was used to estimate unadjusted odds ratios, 95% confidence intervals and P-values.

RESULTS

Twenty-two subjects demonstrated evidence of dynamic hyperinflation during the MST. Thirteen out of 22 subjects were ventilatory limited during exercise including 5 of those without evidence of dynamic hyperinflation (P = 0.24). No combination of variables resulted in a parsimonious regression model.

CONCLUSIONS

Dynamic hyperinflation is common in CF and it is not associated with traditionally defined ventilatory limitation parameters during the MST. Pediatr Pulmonol. 2017;52:29-33. © 2016 Wiley Periodicals, Inc.

Supported and unsupported arm exercise capacity following lung volume reduction surgery: a pilot study

Study Objectives: Lung volume reduction surgery (LVRS) has been shown to improve lung function, leg exercise capacity and quality of life in subjects with severe COPD. This is the first study to examine the effect of LVRS on supported and unsupported arm exercise capacity. Design: Eight subjects with COPD (% pred FEV1 ±SD = 31.1 ± 9.8%) completed testing. At baseline (TI), after eight weeks pulmonary rehabilitation (T2) and four months after LVRS (T3), each subject had tests of lung function, and performed three symptom-limited exercise tests to peak work capacity:supported arm exercise (SAE), unsupported arm exercise (UAE) and leg exercise (LE).Measurements: The FEV1 (% pred) increased from 27.8 ± 7.4 (mean ± SD) at T2 to 36.3 ± 7.1 at T3 (P <0.05). Peak oxygen consumption (VO2) remained similar from TI to T2 for SAE, UAE and LE (all P=1.0) but increased from T2 to T3 (P <0.05) (SAE: T2 = 0.59 ± 0.2 L/min,T3 = 0.72 ± 0.1 L/min; UAE: T2 = 0.45 ± 0.1 L/min, T3 = 0.54 ± 0.1 L/min; LE:T2-0.68 ± 0.2 L/min, T3 = 0.81 ± 0.2 L/min). The ratio of end-expiratory lung volume to total lung capacity was reduced at peak SAE and LE from T2 to T3 (P < 0.01) (SAE:T2 = 81 ± 4.0%, T3 = 76 ± 2.7%; LE: T2-81 ± 5.1%, T3 = 75 ± 3.6%). Conclusion: There was a significant increase in SAE and UAE capacity following LVRS. Dynamic hyperinflation wras reduced during SAE following LVRS.

Airflow limitation following cardiopulmonary exercise testing and heavy-intensity intermittent exercise in children with cystic fibrosis

The clinical importance of exercise testing and training in the healthcare management of young patients with cystic fibrosis (CF) is growing. The aim of the present study was to determine the incidence of airflow limitation following cardiopulmonary exercise testing (CPET) and heavy-intensity intermittent exercise (HIIE) in young patients with CF. Nineteen young patients with CF and respective paired-matched controls performed CPET and HIIE on separate days. Forced expiratory volume in one second (FEV1) was measured pre- and post each exercise modality. A fall in FEV1 of 10 % or greater was used to define airflow limitation. The incidence of airflow limitation was significantly greater in the CF group than in the controls following CPET (32 vs. 5 %; p = 0.03); however, no significant difference in the incidence of airflow limitation was shown following HIIE between the CF group and controls (11 vs. 16 %; p = 0.64).

CONCLUSION

Our data show that the incidence of airflow limitation following CPET in young patients with CF is high. Therefore, clinicians may wish to identify whether young CF patients experience airflow limitation following strenuous exercise, such as CPET, before it is performed. However, HIIE carries a low risk for airflow limitation and may be prescribed as a safe, yet effective exercise modality for young patients with CF.

Effect of abdominal binding on respiratory mechanics during exercise in athletes with cervical spinal cord injury

We asked whether elastic binding of the abdomen influences respiratory mechanics during wheelchair propulsion in athletes with cervical spinal cord injury (SCI). Eight Paralympic wheelchair rugby players with motor-complete SCI (C5-C7) performed submaximal and maximal incremental exercise tests on a treadmill, both with and without abdominal binding. Measurements included pulmonary function, pressure-derived indices of respiratory mechanics, operating lung volumes, tidal flow-volume data, gas exchange, blood lactate, and symptoms. Residual volume and functional residual capacity were reduced with binding (77 ± 18 and 81 ± 11% of unbound, P < 0.05), vital capacity was increased (114 ± 9%, P < 0.05), whereas total lung capacity was relatively well preserved (99 ± 5%). During exercise, binding introduced a passive increase in transdiaphragmatic pressure, due primarily to an increase in gastric pressure. Active pressures during inspiration were similar across conditions. A sudden, sustained rise in operating lung volumes was evident in the unbound condition, and these volumes were shifted downward with binding. Expiratory flow limitation did not occur in any subject and there was substantial reserve to increase flow and volume in both conditions. V̇o2 was elevated with binding during the final stages of exercise (8-12%, P < 0.05), whereas blood lactate concentration was reduced (16-19%, P < 0.05). V̇o2/heart rate slopes were less steep with binding (62 ± 35 vs. 47 ± 24 ml/beat, P < 0.05). Ventilation, symptoms, and work rates were similar across conditions. The results suggest that abdominal binding shifts tidal breathing to lower lung volumes without influencing flow limitation, symptoms, or exercise tolerance. Changes in respiratory mechanics with binding may benefit O2 transport capacity by an improvement in central circulatory function.

Inspiratory Capacity during Exercise: Measurement, Analysis, and Interpretation

Cardiopulmonary exercise testing (CPET) is an established method for evaluating dyspnea and ventilatory abnormalities. Ventilatory reserve is typically assessed as the ratio of peak exercise ventilation to maximal voluntary ventilation. Unfortunately, this crude assessment provides limited data on the factors that limit the normal ventilatory response to exercise. Additional measurements can provide a more comprehensive evaluation of respiratory mechanical constraints during CPET (e.g., expiratory flow limitation and operating lung volumes). These measurements are directly dependent on an accurate assessment of inspiratory capacity (IC) throughout rest and exercise. Despite the valuable insight that the IC provides, there are no established recommendations on how to perform the maneuver during exercise and how to analyze and interpret the data. Accordingly, the purpose of this manuscript is to comprehensively examine a number of methodological issues related to the measurement, analysis, and interpretation of the IC. We will also briefly discuss IC responses to exercise in health and disease and will consider how various therapeutic interventions influence the IC, particularly in patients with chronic obstructive pulmonary disease. Our main conclusion is that IC measurements are both reproducible and responsive to therapy and provide important information on the mechanisms of dyspnea and exercise limitation during CPET.

The evolution of exercise capacity and its limiting factors in cystic fibrosis

The ability to perform exercise is an important determinant of both longevity and quality of life for patients with Cystic Fibrosis. There are a variety of physical and behavioural factors that contribute to exercise limitation. These, such as lung function or habitual physical activity, change over time. However, these factors can also be modified by treatments and interventions. This review discusses the various factors that contribute to exercise limitation in Cystic Fibrosis, and how these change with age.

No effect of arm-crank exercise on diaphragmatic fatigue or ventilatory constraint in Paralympic athletes with cervical spinal cord injury

Cervical spinal cord injury (CSCI) results in a decrease in the capacity of the lungs and chest wall for pressure, volume, and airflow generation. We asked whether such impairments might increase the potential for exercise-induced diaphragmatic fatigue and mechanical ventilatory constraint in this population. Seven Paralympic wheelchair rugby players (mean ± SD peak oxygen uptake = 16.9 ± 4.9 ml·kg−1·min−1) with traumatic CSCI (C5–C7) performed arm-crank exercise to the limit of tolerance at 90% of their predetermined peak work rate. Diaphragm function was assessed before and 15 and 30 min after exercise by measuring the twitch transdiaphragmatic pressure (Pdi,tw) response to bilateral anterolateral magnetic stimulation of the phrenic nerves. Ventilatory constraint was assessed by measuring the tidal flow volume responses to exercise in relation to the maximal flow volume envelope. Pdi,tw was not different from baseline at any time after exercise (unpotentiated Pdi,tw = 19.3 ± 5.6 cmH2O at baseline, 19.8 ± 5.0 cmH2O at 15 min after exercise, and 19.4 ± 5.7 cmH2O at 30 min after exercise; P = 0.16). During exercise, there was a sudden, sustained rise in operating lung volumes and an eightfold increase in the work of breathing. However, only two subjects showed expiratory flow limitation, and there was substantial capacity to increase both flow and volume (<50% of maximal breathing reserve). In conclusion, highly trained athletes with CSCI do not develop exercise-induced diaphragmatic fatigue and rarely reach mechanical ventilatory constraint.

[Dynamic lung hyperinflation and its clinical implication in COPD]

Static lung hyperinflation is defined as the elevation of end- expiratory lung volume above its predicted value, with no increase in end-expiratory alveolar pressure, which remains equal to atmospheric pressure. Dynamic hyperinflation is the transient increase of this volume above the relaxation volume. In patients with COPD, dynamic hyperinflation is mainly determined by the mechanical properties of the respiratory system. Its measurement relies on plethysmography and, during exercise, inspiratory capacity. During exercise, dynamic hyperinflation attenuates expiratory flow limitation but increases the inspiratory loading and induces functional weakness of the diaphragm. It also has haemodynamic consequences and results in more rapid, shallow breathing and progressive reduction in dynamic lung compliance. These events explain exercise intolerance. Several approaches may help combat dynamic hyperinflation and its deleterious clinical effects: bronchodilators, hyperoxia, helium-oxygen mixtures, lung volume reduction surgery...

Non-invasive assessment of exercise performance in children with cystic fibrosis (CF) and non-cystic fibrosis bronchiectasis: is there a CF specific muscle defect?

INTRODUCTION

Peripheral muscle dysfunction is increasingly recognized as complicating respiratory disease, but this is difficult to measure non-invasively.

RESEARCH QUESTION

Can skeletal muscle function and efficiency be measured during exercise non-invasively using respiratory mass spectrometry (RMS); and is the known exercise dysfunction in cystic fibrosis (CF) children related in part to a disease specific defect of skeletal muscle, or a non-specific manifestation of chronic airway infection and inflammation.

METHODS

Calculations of effective pulmonary blood flow and stroke volume, blood oxygen content and oxygen dispatch from the lungs, skeletal muscle oxygen extraction and consumption, anerobic threshold and capacity, and gross, net and work efficiency in 106 controls and 36 children (18 CF) with bronchiectasis, all aged from 8 to 17 years.

RESULTS

Normal values for control subjects are tabulated. CF and non-CF bronchiectatic subjects had similar physiology, and skeletal muscle abnormalities could not be detected. Reduced oxygen dispatch from the lungs, due to an inability to raise stroke volume, without an increase in functional residual capacity was the major factor in reduced exercise ability.

CONCLUSIONS

Non-invasive RMS can be used to determine skeletal muscle function in children. The changes observed in CF subjects were very similar to non-CF bronchiectatic subjects and thus a CF specific defect was not demonstrated.

Breathing Pattern Adopted by Children with Cystic Fibrosis with Mild to Moderate Pulmonary Impairment during Exercise

BACKGROUND

It is well known that severe lung impairment in cystic fibrosis (CF) may compromise respiratory muscle function at rest. Even though patients with CF and severe obstructive lung disease exhibit an abnormal breathing pattern during exercise (due to expiratory flow limitation), patients with CF and normal lung function reportedly have a normal breathing pattern.

OBJECTIVES

The aim of the study was to assess the precise characteristics of the ventilatory pattern adopted during exercise by children with CF and mild to moderate lung disease.

METHODS

Nine children diagnosed as having mild to moderate CF and 9 healthy children with a similar age distribution participated in this study. Both groups performed a continuous incremental cycling protocol. Breathing and timing components were assessed during exercise.

RESULTS

Differences in the breathing pattern between children with CF and controls during exercise are illustrated in Hey plot which described a rapid shallow breathing pattern in children with CF. During exercise, children with CF showed a significantly lower mean inspiratory flow than healthy children (p < 0.001), whereas the mean expiratory flow was higher (p < 0.001). Children with CF also showed a significant increase in the end-tidal carbon dioxide pressure, which may indicate the emergence of hypercapnia.

CONCLUSIONS

During exercise, children with CF (even those not suffering from advanced disease) showed signs of rapid, shallow breathing and an increase in the ventilatory response. This was essentially due to an increase in the mean inspiratory flow, which in turn suggests an expiratory flow limitation. The children were also predisposed to hypercapnia.

Chest wall kinematics, respiratory muscle action and dyspnoea during arm vs. leg exercise in humans

AIM

We hypothesize that different patterns of chest wall (CW) kinematics and respiratory muscle coordination contribute to sensation of dyspnoea during unsupported arm exercise (UAE) and leg exercise (LE).

METHODS

In six volunteer healthy subjects, we evaluated the volumes of chest wall (V(cw)) and its compartments, the pulmonary apposed rib cage (V(rc,p)), the diaphragm-abdomen apposed rib cage (V(rc,a)) and the abdomen (V(ab)), by optoelectronic plethysmography. Oesophageal, gastric and trans-diaphragmatic pressures were simultaneously measured. Chest wall relaxation line allowed the measure of peak rib cage inspiratory muscle, expiratory muscle and abdominal muscle pressures. The loop V(rc,p)/V(rc,a) allowed the calculation of rib cage distortion. Dyspnoea was assessed by a modified Borg scale.

RESULTS

There were some differences and similarities between UAE and LE. Unlike LE with UAE: (i) V(cw) and V(rc,p) at end inspiration did not increase, whereas a decrease in V(rc,p) contributed to decreasing CW end expiratory volume; (ii) pressure production of inspiratory rib cage muscles did not significantly increase from quiet breathing. Not unlike LE, the diaphragm limited its inspiratory contribution to ventilation with UAE with no consistent difference in rib cage distortion between UAE and LE. Finally, changes in abdominal muscle pressure, and inspiratory rib cage muscle pressure predicted 62% and 41.4% of the variability in Borg score with UAE and LE, respectively (P < 0.01).

CONCLUSION

Leg exercise and UAE are associated with different patterns of CW kinematics, respiratory muscle coordination, and production of dyspnoea.

Arm exercise and hyperinflation in patients with COPD: effect of arm training

BACKGROUND

Unlike studies on leg exercise, reports on the regulation of dynamic hyperinflation during arm exercise are scanty. We ascertained the following in patients with COPD: (1) whether and to what extent upper-limb exercise results in dynamic hyperinflation, and (2) the mechanism whereby an arm-training program (ATP) reduces arm effort and dyspnea.

PATIENTS

Twelve patients with moderate-to-severe COPD were tested during incremental, symptom-limited arm exercise after a non-intervention control period (pre-ATP) and after ATP.

METHODS

Exercise testing (1-min increments of 5 W) was performed using an arm ergometer. Oxygen uptake (V(O2)), carbon dioxide output, minute ventilation (Ve), tidal volume, and respiratory rate (RR) were measured continuously during the tests. Inspiratory capacity (IC), exercise dyspnea, and arm effort using a Borg scale were assessed at each step of exercise.

RESULTS

Arm exercise resulted in a significant decrease in IC and significant positive relationships of IC with an increase in V(O2) and exercise dyspnea and arm effort. The results of ATP were as follows: (1) a significant increase in exercise capacity (p < 0.001); (2) no change in the relationships of exercise dyspnea and arm effort with Ve and IC, and of IC with V(O2); (3) at a standardized work rate, Ve, exercise dyspnea, and arm effort significantly decreased, while the decrease in IC was significantly less (p < 0.01) than before the ATP; the decrease in Ve was accomplished primarily by a decrease in RR; and (4) at standardized Ve, exercise dyspnea and arm effort decreased significantly.

CONCLUSIONS

Arm exercise results in the association of dynamic hyperinflation, exercise dyspnea, and arm effort in COPD patients. An ATP increases arm endurance, modulates dynamic hyperinflation, and reduces symptoms.

Dyspnea and leg effort during exercise

Dyspnea and leg effort are the major symptoms limiting exercise in healthy subjects and in patients with a variety of respiratory disorders. Quantitative measurement of both symptoms may be obtained by category scales such as VAS and Borg, with the latter being widely used. Furthermore, descriptor clusters of dyspnea help to assess some of the reasons for stopping exercise. The intensity of dyspnea and leg effort are similar in different disease states; this symmetry suggests that the limiting discomfort is a function of the intensity of increased motor drive to peripheral and respiratory muscles. An alternative explanation for the factors which limit exercise is that the subjects stop exercise volitionally when the discomfort associated with continuing exercise exceeds that which they are willing to tolerate. Muscle strength contributes to the intensity of dyspnea and leg effort at a given power output: the greater the muscle force, the lower the symptom. Symptoms also correlate with intensity and duration of a task by a power function in such a way that when minimizing the intensity of a given muscular task by prolonging the duration of activity, the symptom is drastically reduced. Skeletal muscle fatigue may be a factor limiting exercise tolerance both in healthy subjects and in patients with cardiorespiratory disorders. In conclusion, symptom measurement complements physiological measurements, both being essential to a comprehensive understanding of exercise tolerance.

Arm positioning alters lung volumes in subjects with COPD and healthy subjects

Subjects with chronic obstructive pulmonary disease (COPD) have difficulty performing arm exercise, particularly if the arms are unsupported and elevated. The purpose of this study was to evaluate the effect of arm position on static lung volumes in COPD and healthy subjects. Lung volumes were measured by plethysmography in nine COPD subjects (mean age +/- SD = 67.3 +/- 10.3 years; % pred FEV1 +/- SD = 39.7 +/- 10.9%) and nine healthy subjects (mean age +/- SD = 55.8 +/- 8.8 years; % pred FEV1 +/- SD = 102.9 +/- 12.2%) with the arms below 90 degrees shoulder flexion, at 90 degrees shoulder flexion and above 90 degrees shoulder flexion. In all subjects a significant increase in functional residual capacity (FRC) and reduction in inspiratory capacity (IC) was shown with arms above 90 degrees shoulder flexion when compared with both arms below 90 degrees shoulder flexion (mean increase in FRC (95% CI) was 0.17 L (0.06 to 0.27) for COPD and 0.29 L (0.11 to 0.47) for healthy subjects; mean reduction in IC (95% CI) was 0.24 L (0.1 to 0.38) for COPD and 0.45 L (0.22 to 0.68) for healthy subjects) and arms at 90 degrees shoulder flexion (mean increase in FRC (95% CI) was 0.15 L (0.01 to 0.29) for COPD and 0.22 L (0.11 to 0.34) for healthy subjects; mean reduction in IC (95% CI) was 0.14 L (0.01 to 0.26) for COPD and was 0.29 L (0.17 to 0.42) for healthy subjects). These changes may alter lung mechanics and, in COPD subjects, may affect their ability to perform arm exercise above shoulder height

Arm exercise capacity and dyspnea ratings in subjects with chronic obstructive pulmonary disease

PURPOSE

This study aimed to compare the metabolic, ventilatory, and dyspnea responses to unsupported arm exercise, supported arm exercise and leg exercise between subjects with chronic obstructive pulmonary disease (COPD) and healthy age-matched controls.

METHODS

For this study, 21 subjects with COPD (mean age, 62 +/- 2 years; predicted forced expiratory volume in 1 second [FEV(1)], 37 +/- 3%) and 7 healthy age-matched control subjects (% pred FEV(1) = 109 +/- 5%) were included in the analyses of three incremental exercise tests to peak work capacity: unsupported arm exercise, supported arm exercise (arm ergometry), and leg exercise (cycle ergometry). Work level, oxygen consumption (VO(2)), minute ventilation (V(E)), dyspnea, and rate of perceived exertion were measured each minute.

RESULTS

Peak work level and peak VO(2) were significantly reduced in the subjects with COPD for all exercise tests (P <.01 for all), as compared with the control subjects. Within the COPD group, the VO(2) and V(E) at peak exercise were significantly lower for unsupported arm exercise than for both the leg and supported arm exercises (both P <.001). The ratio of V(E) to maximal voluntary ventilation was high for leg exercise (96%), supported arm exercise (91%), and unsupported arm exercise (77%) among the subjects with COPD. At a given percentage of VO(2) peak, dyspnea scores were similar for all the exercise tests.

CONCLUSIONS

Ventilatory constraints limit exercise performance in COPD. The lowest amount of work, in terms of VO(2,), was during unsupported arm exercise. Because the subjects with COPD had scores showing similar levels of dyspnea at the same percentage of VO(2) peak, it is suggested that patients be encouraged to reach equivalent dyspnea levels when performing unsupported and supported arm exercise training and leg training.

Changes in pulmonary mechanics with increasing disease severity in children and young adults with cystic fibrosis

As forced expiratory volume in 1 second (FEV(1)) is a major predictor of outcome in patients with cystic fibrosis (CF), we investigated the effect of FEV(1) on pulmonary mechanics in children and young adults with CF. We measured respiratory rate; tidal volume; minute ventilation; arterial blood gases; sniff esophageal pressure; dynamic lung compliance; total pulmonary resistance; intrinsic positive end expiratory pressure; and total, elastic, and resistive work of breathing in 32 patients (FEV(1) range: 12-49% predicted). We observed correlations between FEV(1) and Pa(O(2)) (r = 0.76, p < 0.0001) and Pa(CO(2)) (r = -0.70, p < 0.0001), FEV(1) and respiratory rate/tidal volume (r = -0.41, p = 0.02), FEV(1) and dynamic lung compliance (r = 0.64, p < 0.0001), and FEV(1) and total work of breathing (r = -0.52, p = 0.002) and elastic work of breathing (r = -0.60. p = 0.0003). No correlations were observed between FEV(1) and sniff esophageal pressure (p = 0.5), minute ventilation (p = 0.9), total pulmonary resistance (p = 0.3), intrinsic positive end expiratory pressure (p = 0.3), or resistive work of breathing (p = 0.1). As FEV(1) declines in children and young adults with CF, there is an increase in the elastic load and work of breathing, resulting in a rapid shallow breathing pattern, that is associated with further impairment of gas exchange.

Respiratory response during arm elevation in isolated diaphragm weakness

Upper extremity exercise is associated with a significant metabolic and ventilatory cost that is particularly evident in patients with severe chronic airflow obstruction. In these patients abnormal ventilatory muscle recruitment has been hypothesized to relate to impaired diaphragm function resulting from hyperinflation. Similar data have never been reported in patients with isolated diaphragm weakness but without airflow obstruction or hyperinflation, a group that would ideally define the role of diaphragm function during arm elevation (AE). We prospectively studied 15 patients with isolated diaphragm weakness of varying severity (Pdi(sniff), 31.74 +/- 3.75 cm H(2)O) as contrasted with eight normal subjects (Pdi(sniff), 111. 77 +/- 13.35 cm H(2)O) of similar age. Patients with diaphragm weakness demonstrated significant lung volume restriction with normal DL(CO)/VA. There was no difference in resting oxygen consumption (V O(2)), carbon dioxide production (V CO(2)), minute ventilation (V E), and tidal volume (VT) between the two groups; however, a borderline difference in resting breathing frequency (f(b)) (p = 0.056) was evident. Both groups demonstrated a rise in V O(2), V CO(2), and V E during 2 min of AE anteriorly. Normal subjects demonstrated a statistically significant rise in VT but a statistically insignificant rise in f(b) during AE. In contrast, patients with diaphragm weakness demonstrated a statistically significant rise in f(b) during AE but a statistically insignificant rise in VT. In patients the observed rise in VT directly correlated with baseline Pdi(sniff) (r = 0.59, p = 0.02) and Pdi(max) (r = 0.81, p = 0.002). Both groups demonstrated a rise in Pdi during AE. The rise in Pdi during AE directly correlated to Pdi(sniff) in the patients (r = 0.69, p = 0.004). Observed end-expiratory Ppl rose during arm elevation in both the patient group and in the normal control group, but no evidence of a differential response to AE was found. In those patients with greater diaphragm weakness (Pdi(sniff) < 30 cm H(2)O), abnormal respiratory muscle function (lesser rise in Pdi) and a lesser increase in VT during AE were more evident. These data highlight the importance of diaphragm function in determining the metabolic and respiratory muscle response to arm elevation.