Regulation of ventilatory capacity during exercise in asthmatics

1995 ◽  
Vol 79 (3) ◽  
pp. 892-901 ◽  
Author(s):  
B. D. Johnson ◽  
P. D. Scanlon ◽  
K. C. Beck
Keyword(s):  
Exercise Capacity ◽  
Lung Volume ◽  
Maximal Exercise ◽  
Minute Ventilation ◽  
Constant Load ◽  
Flow Limitation ◽  
Ventilatory Capacity ◽  
Ventilatory Reserve ◽  
Maximal Exercise Capacity ◽  
Bronchomotor Tone

In asthmatic and control subjects, we examined the changes in ventilatory capacity (VECap), end-expiratory lung volume (EELV), and degree of flow limitation during three types of exercise: 1) incremental, 2) constant load (50% of maximal exercise capacity; 36 min), and 3) interval (alternating between 60 and 40% of maximal exercise capacity; 6-min workloads for 36 min). The VECap and degree of flow limitation at rest and during the various stages of exercise were estimated by aligning the tidal breathing flow-volume (F-V) loops within the maximal expiratory F-V (MEFV) envelope using the measured EELV. In contrast to more usual estimates of VECap (i.e., maximal voluntary ventilation and forced expiratory volume in 1 s x 40), the calculated VECap depended on the existing bronchomotor tone, the lung volume at which the subjects breathed (i.e., EELV), and the tidal volume. During interval and constant-load exercise, asthmatic subjects experienced reduced ventilatory reserve, higher degrees of flow limitation, and had higher EELVs compared with nonasthmatic subjects. During interval exercise, the VECap of the asthmatic subjects increased and decreased with variations in minute ventilation, due in part to alterations in their MEFV curve as exercise intensity varied between 60 and 49% of maximal capacity. In conclusion, asthmatic subjects have a more variable VECap and reduced ventilatory reserve during exercise compared with nonasthmatic subjects. The variations in VECap are due in part to a more labile MEFV curve secondary to changes in bronchomotor tone. Asthmatics defend VECap and minimize flow limitation by increasing EELV.

Effect of mild-to-moderate airflow limitation on exercise capacity

1991 ◽  
Vol 70 (1) ◽  
pp. 223-230 ◽  
Author(s):  
T. G. Babb ◽  
R. Viggiano ◽  
B. Hurley ◽  
B. Staats ◽  
J. R. Rodarte
Keyword(s):  
Exercise Capacity ◽  
Vital Capacity ◽  
Maximal Exercise ◽  
Minute Ventilation ◽  
Airflow Limitation ◽  
Maximal Heart Rate ◽  
Lung Capacity ◽  
Close Relationship ◽  
Response To Exercise ◽  
Maximal Exercise Capacity

To determine the effect of mild-to-moderate airflow limitation on exercise tolerance and end-expiratory lung volume (EELV), we studied 9 control subjects with normal pulmonary function [forced expired volume in 1 s (FEV1) 105% pred; % of forced vital capacity expired in 1 s (FEV1/FVC%) 81] and 12 patients with mild-to-moderate airflow limitation (FEV1 72% pred; FEV1/FVC % 58) during progressive cycle ergometry. Maximal exercise capacity was reduced in patients [69% of pred maximal O2 uptake (VO2max)] compared with controls (104% pred VO2max, P less than 0.01); however, maximal expired minute ventilation-to-maximum voluntary ventilation ratio and maximal heart rate were not significantly different between controls and patients. Overall, there was a close relationship between VO2max and FEV1 (r2 = 0.62). Resting EELV was similar between controls and patients [53% of total lung capacity (TLC)], but at maximal exercise the controls decreased EELV to 45% of TLC (P less than 0.01), whereas the patients increased EELV to 58% of TLC (P less than 0.05). Overall, EELV was significantly correlated to both VO2max (r = -0.71, P less than 0.001) and FEV1 (r = -0.68, P less than 0.001). This relationship suggests a ventilatory influence on exercise capacity; however, the increased EELV and associated pleural pressures could influence cardiovascular function during exercise. We suggest that the increase in EELV should be considered a response reflective of the effect of airflow limitation on the ventilatory response to exercise.

scholarly journals Effect of Six-Minute Walk Test and Incremental Exercise on Inspiratory Capacity, Ventilatory Constraints, Breathlessness and Exercise Performance in Sedentary Male Smokers without Airway Obstruction

2021 ◽  
Vol 18 (23) ◽  
pp. 12665
Author(s):  
Wassim Melliti ◽  
Rim Kammoun ◽  
Donies Masmoudi ◽  
Said Ahmaidi ◽  
Kaouthar Masmoudi ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Lung Volume ◽  
Maximal Exercise ◽  
Ventilatory Threshold ◽  
Minute Ventilation ◽  
Pulmonary Function Tests ◽  
Exercise Intolerance ◽  
Dynamic Hyperinflation ◽  
Walk Test ◽  
Inspiratory Capacity

We investigated physiological responses and exercise capacity in sedentary young smokers during sub-maximal and maximal test and its impact on dyspnea and exercise intolerance. Fifty sedentary male smokers and non-smokers (age: 24 ± 1 years., weight: 71 ± 9 kg, height: 177.3 ± 4.8 cm, body mass index: 22.6 ± 2.5 kg/m2) underwent two visits with pulmonary function tests, breathing pattern, and inspiratory capacity measurement at rest and during sub-maximal and maximal exercise. Smokers show reduced exercise capacity during six minutes walk test (6-MWT) with decreased walked distance (p < 0.001) and inspiratory capacity (p < 0.05). During cardiopulmonary exercise test (CPET), smokers had higher minute ventilation VE for a given submaximal intensity (p < 0.05) and lower minute ventilation at maximal exercise (p < 0.001). End expiratory lung volume was significantly lower in sedentary smokers at rest (p < 0.05), at ventilatory threshold during exercise (p < 0.05), but not during peak exercise. End inspiratory lung volume was significantly lower in smokers at rest (p < 0.05) and ventilatory threshold (p < 0.05). Cigarette smoking alters lung function during submaximal and maximal exercise. This alteration is manifested by the development of dynamic hyperinflation contributing to exercise capacity limitation.

scholarly journals A Low-Carbohydrate Ketogenic Diet and Treadmill Training Enhanced Fatty Acid Oxidation Capacity but Did Not Enhance Maximal Exercise Capacity in Mice

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 611
Author(s):  
Sihui Ma ◽  
Jiao Yang ◽  
Takaki Tominaga ◽  
Chunhong Liu ◽  
Katsuhiko Suzuki
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Exercise Capacity ◽  
Ketogenic Diet ◽  
Maximal Exercise ◽  
Treadmill Running ◽  
Acid Oxidation ◽  
Oxidation Capacity ◽  
Low Carbohydrate ◽  
Maximal Exercise Capacity

The low-carbohydrate ketogenic diet (LCKD) is a dietary approach characterized by the intake of high amounts of fat, a balanced amount of protein, and low carbohydrates, which is insufficient for metabolic demands. Previous studies have shown that an LCKD alone may contribute to fatty acid oxidation capacity, along with endurance. In the present study, we combined a 10-week LCKD with an 8-week forced treadmill running program to determine whether training in conjunction with LCKD enhanced fatty acid oxidation capacity, as well as whether the maximal exercise capacity would be affected by an LCKD or training in a mice model. We found that the lipid pool and fatty acid oxidation capacity were both enhanced following the 10-week LCKD. Further, key fatty acid oxidation related genes were upregulated. In contrast, the 8-week training regimen had no effect on fatty acid and ketone body oxidation. Key genes involved in carbohydrate utilization were downregulated in the LCKD groups. However, the improved fatty acid oxidation capacity did not translate into an enhanced maximal exercise capacity. In summary, while favoring the fatty acid oxidation system, an LCKD, alone or combined with training, had no beneficial effects in our intensive exercise-evaluation model. Therefore, an LCKD may be promising to improve endurance in low- to moderate-intensity exercise, and may not be an optimal choice for those partaking in high-intensity exercise.

Development of the A‐STEP: A new incremental maximal exercise capacity step test in cystic fibrosis

2021 ◽  
Author(s):  
Lisa M. Wilson ◽  
Matthew J. Ellis ◽  
Rebecca L. Lane ◽  
John W. Wilson ◽  
Dominic T. Keating ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Exercise Capacity ◽  
Maximal Exercise ◽  
Step Test ◽  
Maximal Exercise Capacity

scholarly journals Limited Maximal Exercise Capacity in Patients With Chronic Heart Failure

2010 ◽  
Vol 55 (18) ◽  
pp. 1945-1954 ◽  
Author(s):  
Fabio Esposito ◽  
Odile Mathieu-Costello ◽  
Ralph Shabetai ◽  
Peter D. Wagner ◽  
Russell S. Richardson
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Exercise Capacity ◽  
Maximal Exercise ◽  
Maximal Exercise Capacity

scholarly journals Impacts of Respiratory Muscle Training on Respiratory Functions, Maximal Exercise Capacity, Functional Performance, and Quality of Life in School-Aged Children with Postoperative Congenital Diaphragmatic Hernia

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Samah A. Moawd ◽  
Alshimaa R. Azab ◽  
Zizi M. Ibrahim ◽  
Anju Verma ◽  
Walid Kamal Abdelbasset
Keyword(s):  
Quality Of Life ◽  
Exercise Capacity ◽  
Respiratory Muscle ◽  
Maximal Exercise ◽  
Functional Performance ◽  
Respiratory Muscle Training ◽  
Muscle Training ◽  
School Aged Children ◽  
Maximal Exercise Capacity

Objectives. Congenital diaphragmatic hernia (CDH) is a birth defect affecting the respiratory functions, functional performance, and quality of life (QOL) in school-aged children. Rarely have studies been conducted to evaluate the impacts of respiratory muscle training on school-aged children with postoperative CDH. The current study was designed to evaluate the impacts of respiratory muscle training on respiratory function, maximal exercise capacity, functional performance, and QOL in these children. Methods. This study is a randomized control study. 40 children with CDH (age: 9-11 years) were assigned randomly into two groups. The first group conducted an incentive spirometer exercise combined with inspiratory muscle training (study group, n=20), whereas the second group conducted only incentive spirometer exercise (control group, n=20), thrice weekly for twelve consecutive weeks. Respiratory functions, maximal exercise capacity, functional performance, and pediatric quality of life inventory (PedsQL) were assessed before and after the treatment program. Results. Regarding the posttreatment analysis, the study group showed significant improvements in all outcome measures (FVC%, p<0.001; FEV1%, p=0.002; VO2max, p=0.008; VE/VCO2 slope, p=0.002; 6-MWT, p<0.001; and PedsQL, p<0.001), whereas the control group did not show significant changes (p>0.05). Conclusion. Respiratory muscle training may improve respiratory functions, maximal exercise capacities, functional performance, and QOL in children with postoperative CDH. Clinical commendations have to be considered to include respiratory muscle training in pulmonary rehabilitation programs in children with a history of CDH.

scholarly journals Left atrial function and maximal exercise capacity in heart failure with preserved and mid‐range ejection fraction

2020 ◽  
Author(s):  
Caterina Maffeis ◽  
Daniel Armando Morris ◽  
Evgeny Belyavskiy ◽  
Martin Kropf ◽  
Aravind Kumar Radhakrishnan ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Exercise Capacity ◽  
Left Atrial ◽  
Maximal Exercise ◽  
Atrial Function ◽  
Left Atrial Function ◽  
Maximal Exercise Capacity
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