The Influence of the Self-Contained Breathing Apparatus (SCBA) on Ventilatory Function and Maximal Exercise

2005 ◽  
Vol 30 (5) ◽  
pp. 507-519 ◽  
Author(s):  
Neil D. Eves ◽  
Richard L. Jones ◽  
Stewart R. Petersen
Keyword(s):  
Maximal Oxygen Consumption ◽  
The Self ◽  
Resistive Load ◽  
Expiratory Flow Limitation ◽  
Exercise Tests ◽  
Low Resistance ◽  
Breathing Resistance ◽  
Breathing Apparatus ◽  
Mouth Pressure ◽  
Key Words Ventilation

Our previous work showed that breathing low density gases during exercise with the self-contained breathing apparatus (SCBA) improves maximal ventilation (VE) and maximal oxygen consumption [Formula: see text] This suggests that the SCBA limits exercise by adding a resistive load to breathing. In this study we compared [Formula: see text] with and without the various components comprising the SCBA to determine their impact on [Formula: see text] Twelve males performed 4 randomly ordered incremental exercise tests to exhaustion on a treadmill: (1) low-resistance breathing valve only (CON); (2) full SCBA (SCBA); (3) SCBA regulator only (REG); and (4) carrying the cylinder and harness assembly but breathing through a low-resistance breathing valve (PACK). Compared to CON, [Formula: see text] was reduced to a similar extent in the SCBA and REG trials (14.9% and 13.1%, respectively). The PACK condition also reduced [Formula: see text] but to a lesser extent (4.8 ± 5.3%). At [Formula: see text][Formula: see text] was decreased and expiratory mouth pressure and external breathing resistance (BR) were increased in both the SCBA and REG trials. There was a significant correlation between the change in maximal [Formula: see text] and [Formula: see text] with the SCBA. The results show that the SCBA reduces [Formula: see text] by limiting [Formula: see text] secondary to the increased BR of the SCBA regulator. Key words: ventilation, breathing resistance, expiratory flow limitation, [Formula: see text]

Work of breathing is increased during exercise with the self-contained breathing apparatus regulator

2006 ◽  
Vol 31 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Scott J. Butcher ◽  
Richard L. Jones ◽  
Neil D. Eves ◽  
Stewart R. Petersen
Keyword(s):  
Work Of Breathing ◽  
The Self ◽  
Healthy Male ◽  
Lung Volumes ◽  
Low Resistance ◽  
Breathing Apparatus ◽  
Esophageal Balloon ◽  
Ventilation Rates ◽  
Male Subjects ◽  
Body Plethysmograph

The self-contained breathing apparatus (SCBA) increases the expiratory pressure required to maintain high rates of ventilation, suggesting that the expiratory work of breathing (WOB) is increased; however, this has never been reported. The objective of this study, therefore, was to determine if the WOB is increased with the SCBA regulator (BA condition) compared with a low-resistance breathing valve (RV condition) during exercise. Twelve healthy male subjects underwent two randomized exercise trials, consisting of cycling at 150, 180, 210, and 240 W. Inspired and expired tidal volumes were measured using a body plethysmograph, whereas esophageal pressures were measured with an esophageal balloon. Modified Campbell diagrams were created to calculate the resistive and elastic components of WOB during inspiration and expiration. There were no differences in WOB between BA and RV conditions at 150 W. End-inspiratory and -expiratory lung volumes were elevated (p < 0.05) in the BA condition at higher ventilation rates, which increased inspiratory elastic work and decreased expiratory elastic work at 180 and 210 W (p < 0.05). At 240 W (VE = 112 ± 17 L·min–1 in the BA condition), active expiratory resistive work increased by 59% ± 51%, inspiratory elastic work increased by 26% ± 24%, and total WOB increased by 13% ± 12% in the BA condition (p < 0.05). The SCBA regulator causes an increase in the active expiratory resistive work to maintain high ventilatory rates and an increase inspiratory elastic work through an elevation in lung volumes.

scholarly journals Cardiorespiratory fitness assessment using risk-stratified exercise testing and dose–response relationships with disease outcomes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomas I. Gonzales ◽  
Kate Westgate ◽  
Tessa Strain ◽  
Stefanie Hollidge ◽  
Justin Jeon ◽  
...  
Keyword(s):  
Cardiorespiratory Fitness ◽  
Maximal Oxygen Consumption ◽  
Estimation Method ◽  
The Novel ◽  
Exercise Tests ◽  
Metabolic Equivalent ◽  
Fitness Assessment ◽  
Disease Outcomes ◽  
All Cause Mortality ◽  
The Uk

AbstractCardiorespiratory fitness (CRF) is associated with mortality and cardiovascular disease, but assessing CRF in the population is challenging. Here we develop and validate a novel framework to estimate CRF (as maximal oxygen consumption, VO2max) from heart rate response to low-risk personalised exercise tests. We apply the method to examine associations between CRF and health outcomes in the UK Biobank study, one of the world’s largest and most inclusive studies of CRF, showing that risk of all-cause mortality is 8% lower (95%CI 5–11%, 2670 deaths among 79,981 participants) and cardiovascular mortality is 9% lower (95%CI 4–14%, 854 deaths) per 1-metabolic equivalent difference in CRF. Associations obtained with the novel validated CRF estimation method are stronger than those obtained using previous methodology, suggesting previous methods may have underestimated the importance of fitness for human health.

Influence of prior ventilatory experience on the estimation of breathlessness during exercise

1990 ◽  
Vol 78 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Rachel C. Wilson ◽  
P. W. Jones
Keyword(s):  
Exercise Test ◽  
Prior Experience ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Resistive Load ◽  
Inspiratory Time ◽  
Borg Scale ◽  
Exercise Tests ◽  
Loaded Breathing ◽  
Inspiratory Load

1. The intensity of breathlessness was measured during exercise in nine normal subjects using a modified Borg scale to examine the effect of prior experience of breathlessness on subsequent estimates of breathlessness. 2. Each subject performed four exercise tests, each of which consisted of two identical runs of workload incrementation (run 1 and run 2). An inspiratory resistive load of 3.8 cmH2O s−1 l−1 was applied during the appropriate run of the exercise test to examine the effect of (a) prior experience of ‘loaded’ breathing on breathlessness estimation during ‘unloaded’ breathing, and (b) prior experience of ‘unloaded’ breathing on breathlessness estimation during ‘loaded’ breathing. Run 1 was the conditioning run; run 2 was the run in which the effect of conditioning was measured. 3. There was a good correlation between breathlessness and minute ventilation during both unloaded’ breathing (median r = 0.93) and ‘loaded’ breathing (median r = 0.95). 4. The slope of the Borg score/minute ventilation relationship was greater during ‘loaded’ breathing than during ‘unloaded’ breathing (P < 0.01). There was no difference in mean Borg score between ‘unloaded’ and ‘loaded’ breathing. 5. After a period of ‘loaded’ breathing during run 1, estimated breathlessness was significantly reduced during ensuing ‘unloaded’ breathing in run 2 (P < 0.01) compared with the exercise test in which ‘unloaded’ breathing was experienced throughout both run 1 and run 2. 6. After a period of ‘unloaded’ breathing in run 1, estimated breathlessness was significantly increased during ensuing ‘loaded’ breathing in run 2 (P < 0.01) compared with the exercise test in which the inspiratory load had already been experienced in run 1. 7. Changes in the pattern of breathing (inspiratory time, expiratory time, total breath duration, inspiration time/total breath duration ratio and tidal volume) were not consistent with the changes in breathlessness. 8. We suggest that perception of breathlessness may be influenced by a subject's immediate prior experience of an altered relationship between breathlessness and ventilation.

scholarly journals Simulation of a Breathing Apparatus on Chemically Bound Oxygen with a Circular Pendulum Circuit of the Air Duct Part

2021 ◽  
pp. 46-52
Author(s):  
S.G. Ekhilevskiy ◽  
◽  
O.V. Golubeva ◽  
E.P. Potapenko ◽  
◽  
...  
Keyword(s):  
Maximum Permissible Concentration ◽  
Protective Action ◽  
Dead Layer ◽  
Respiratory Protection ◽  
Sorbent Layer ◽  
Breathing Resistance ◽  
Breathing Apparatus ◽  
Short Period ◽  
The Dead ◽  
Made In

At present, the main prospects for improving the insulating means of respiratory protection are associated with the chemical method of oxygen reservation. The arguments in favor of this choice are the high packing density of oxygen and its self-regulating supply, depending on the physical activity of a person. The main schemes of the air duct part of breathing apparatus on chemically bound oxygen are circular and pendulum. The attempt is made in the article to combine the advantages of the circular (small harmful space) and pendulum (small volume of the dead layer) schemes of breathing apparatus on chemically bound oxygen. For these purposes, the formalism method was developed, which allows mathematically and with the help of a computer to simulate the dynamic sorption activity of the regenerative cartridge of a breathing apparatus with a hybrid (circular-pendulum) scheme of the air duct part. The increase in the protective action of the apparatus is determined due to the use of the resource of the dead sorbent layer in the result of the air flow reverse in the pendulum part of the regenerative cartridge. Feasibility of using a hybrid scheme in the self-rescuers with a short period of protective action is shown. The optimal length of the pendulum part is determined, at which the breathing resistance decreases, and the harmful space occupied by the air returning for inhalation without contact with the unreacted layers of the oxygen-containing product is not increased. Its weak dependence on the total length of the regenerative cartridge and the maximum permissible concentration of carbon dioxide in the air returning to inhalation is shown, which makes the circular pendulum scheme realizable in practice.

Exercise-induced arterial hypoxemia is unaffected by intense physical training: a case report

2014 ◽  
Vol 39 (2) ◽  
pp. 266-269 ◽  
Author(s):  
Paolo B. Dominelli ◽  
Glen E. Foster ◽  
Giulio S. Dominelli ◽  
William R. Henderson ◽  
Michael S. Koehle ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Case Report ◽  
Aerobic Training ◽  
Maximal Exercise ◽  
Maximal Oxygen Consumption ◽  
Severe Hypoxemia ◽  
Exercise Tests ◽  
Arterial Hypoxemia ◽  
Healthy Humans ◽  
Exercise Induced

Exercise-induced arterial hypoxemia (EIAH) occurs in some healthy humans at sea-level, whereby the most aerobically trained individuals develop the most severe hypoxemia. A female competitive runner completed 2 maximal exercise tests. Maximal oxygen consumption increased by 15% between testing days, but the degree of hypoxemia remained similar (PaO2, SaO2; 82 and 80 mm Hg; 93.8% and 92.8%; first and second test, respectively). Our case indicates that EIAH does not necessarily worsen with aerobic training.

Effects of the self-contained breathing apparatus on left-ventricular function at rest and during graded exercise

2009 ◽  
Vol 34 (4) ◽  
pp. 625-631 ◽  
Author(s):  
Jonathan R. Mayne ◽  
Mark J. Haykowsky ◽  
Michael D. Nelson ◽  
Timothy C. Hartley ◽  
Scott J. Butcher ◽  
...  
Keyword(s):  
Free Breathing ◽  
Esophageal Pressure ◽  
Left Ventricular ◽  
The Self ◽  
Peak Oxygen Consumption ◽  
Moderate Intensity ◽  
Lv Function ◽  
Moderate Intensity Exercise ◽  
Similar Reduction ◽  
Breathing Apparatus

The purpose of this study was to examine the effects of the self-contained breathing apparatus (SCBA) on left-ventricular (LV) function at rest and during mild- to moderate-intensity exercise, using 2-dimensional echocardiography. Twenty-three healthy male volunteers exercised on a stair-climber at work rates equivalent to 50%, 60%, 70%, and 80% of peak oxygen consumption. Esophageal pressure LV diastolic and systolic cavity areas, and myocardial areas were acquired during the final minute of each stage of exercise. As expected, the esophageal pressure response during SCBA breathing revealed significantly lower (more negative) inspiratory pressures and higher (more positive) expiratory pressures and, consequently, higher pressure swings, than free breathing (FB). End-diastolic cavity area (EDCA) and end-systolic cavity area (ESCA) were lower with the SCBA than with FB. LV contractility was higher (p < 0.05) with the SCBA, which can partially be explained by decreases in end-systolic wall stress. Therefore, the SCBA was found to decrease LV preload during moderate-intensity exercise, but did not negatively affect stroke area because of a similar reduction in ESCA.

Researched on the Characteristics of Self-Excited Induction Generator

2013 ◽  
Vol 860-863 ◽  
pp. 2252-2255
Author(s):  
Wei Min Chen ◽  
De Zhi Qi ◽  
Nan Xie ◽  
Hui Cai
Keyword(s):  
Output Voltage ◽  
Asynchronous Motor ◽  
Open Loop ◽  
The Self ◽  
Induction Generator ◽  
Resistive Load ◽  
Energy Technology ◽  
New Energy ◽  
Asynchronous Generator

Micro-hydro as a new energy technology, has good prospects for development.On some occasions which dont control, the generator usually choose self-excited induction generator.The paper presents a method which the asynchronous motor can instead of the induction generator, and calculate compensation capacitance of the self-excited induction generator. Finally,this paper verified by experiments, which the changes of the output voltage and frequency and the changes of harmonic by changing the resistive load, when the asynchronous generator open-loop runs. The results show that,this method has feasibility and validity.

The Na+-K+-ATPase α2 gene and trainability of cardiorespiratory endurance: the HERITAGE Family Study

2000 ◽  
Vol 88 (1) ◽  
pp. 346-351 ◽  
Author(s):  
Tuomo Rankinen ◽  
Louis Pérusse ◽  
Ingrid Borecki ◽  
Yvon C. Chagnon ◽  
Jacques Gagnon ◽  
...  
Keyword(s):  
Maximal Oxygen Consumption ◽  
Endurance Performance ◽  
Cycle Ergometer ◽  
Electrolyte Balance ◽  
Exercise Tests ◽  
Maximal Power Output ◽  
Length Polymorphisms ◽  
Ergometer Exercise ◽  
Exon 1 ◽  
N 93

The Na+-K+-ATPase plays an important role in the maintenance of electrolyte balance in the working muscle and thus may contribute to endurance performance. This study aimed to investigate the associations between genetic variants at the Na+-K+-ATPase α2 locus and the response (Δ) of maximal oxygen consumption (V˙o 2 max) and maximal power output (W˙max) to 20 wk of endurance training in 472 sedentary Caucasian subjects from 99 families. V˙o 2 max andW˙max were measured during two maximal cycle ergometer exercise tests before and again after the training program, and restriction fragment length polymorphisms at the Na+-K+-ATPase α2 (exons 1 and 21–22 with Bgl II) gene were typed. Sibling-pair linkage analysis revealed marginal evidence for linkage between the α2 haplotype and ΔV˙o 2 max ( P= 0.054) and stronger linkages between the α2 exon 21–22 marker ( P = 0.005) and α2 haplotype ( P = 0.003) and ΔW˙max. In the whole cohort, ΔV˙o 2 max in the 3.3-kb homozygotes of the exon 1 marker ( n = 5) was 41% lower than in the 8.0/3.3-kb heterozygotes ( n = 87) and 48% lower than in the 8.0-kb homozygotes ( n = 380; P = 0.018, adjusted for age, gender, baselineV˙o 2 max, and body weight). Among offspring, 10.5/10.5-kb homozygotes ( n = 14) of the exon 21–22 marker showed a 571 ± 56 (SE) ml O2/min increase inV˙o 2 max, whereas the increases in the 10.5/4.3-kb ( n = 93) and 4.3/4.3-kb ( n= 187) genotypes were 442 ± 22 and 410 ± 15 ml O2/min, respectively ( P = 0.017). These data suggest that genetic variation at the Na+-K+-ATPase α2 locus influences the trainability ofV˙o 2 max in sedentary Caucasian subjects.

Sign in / Sign up

Export Citation Format

Share Document