Relative contributions of chemical and non-chemical drives to the breath-holding time in breath-hold divers (ama).

Breath holding to the breaking point was studied at FRC in six healthy subjects in the sitting position. Breath-holding time increased with successive trials within experimental sessions in all subjects. To study the influence of Valsalva and Mueller maneuvers on breath-holding performance, sustained inspiratory or expiratory effort against an occluded mouthpiece was initiated 5 s before the anticipated breaking point, determined in previous trials. The subject tried to maintain a target mouth pressure of +20 or -20 cmH2O, displayed on an oscilloscope, for the remainder of the breath hold. Both types of maneuver consistently prolonged breath-holding time in all subjects. However, a control maneuver, in which the subjects squeezed rubber bulbs with their hands, was equally effective in prolonging breath-holding time. The results demonstrate the important influence of psychological factors on breath-holding performance and emphasize the need for caution in the interpretation of effects of “relieving maneuvers” on breath-holding time.

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An Impact of Yogic Practices and Weight Training on Breath Holding Time of College Men Players

PARIPEX-INDIAN JOURNAL OF RESEARCH ◽

10.15373/22501991/jan2014/78 ◽

2012 ◽

Vol 3 (1) ◽

pp. 7-8

Author(s):

Dr. A. S. NAGESWARAN Dr. A. S. NAGESWARAN ◽

Keyword(s):

Weight Training ◽

College Men ◽

Holding Time ◽

Breath Holding

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Comparison of Compressed Sensing and Gradient and Spin-Echo in Breath-Hold 3D MR Cholangiopancreatography: Qualitative and Quantitative Analysis

Diagnostics ◽

10.3390/diagnostics11040634 ◽

2021 ◽

Vol 11 (4) ◽

pp. 634

Author(s):

Weon Jang ◽

Ji Soo Song ◽

Sang Heon Kim ◽

Jae Do Yang

Keyword(s):

Image Quality ◽

Compressed Sensing ◽

Spin Echo ◽

Contrast Ratio ◽

Rank Test ◽

Breath Holding ◽

Breath Hold ◽

Background Suppression ◽

Time Saving ◽

Noise Ratio

While magnetic resonance cholangiopancreatography (MRCP) is routinely used, compressed sensing MRCP (CS-MRCP) and gradient and spin-echo MRCP (GRASE-MRCP) with breath-holding (BH) may allow sufficient image quality with shorter acquisition times. This study qualitatively and quantitatively compared BH-CS-MRCP and BH-GRASE-MRCP and evaluated their clinical effectiveness. Data from 59 consecutive patients who underwent both BH-CS-MRCP and BH-GRASE-MRCP were qualitatively analyzed using a five-point Likert-type scale. The signal-to-noise ratio (SNR) of the common bile duct (CBD), contrast-to-noise ratio (CNR) of the CBD and liver, and contrast ratio between periductal tissue and the CBD were measured. Paired t-test, Wilcoxon signed-rank test, and McNemar’s test were used for statistical analysis. No significant differences were found in overall image quality or duct visualization of the CBD, right and left 1st level intrahepatic duct (IHD), cystic duct, and proximal pancreatic duct (PD). BH-CS-MRCP demonstrated higher background suppression and better visualization of right (p = 0.004) and left 2nd level IHD (p < 0.001), mid PD (p = 0.003), and distal PD (p = 0.041). Image quality degradation was less with BH-GRASE-MRCP than BH-CS-MRCP (p = 0.025). Of 24 patients with communication between a cyst and the PD, 21 (87.5%) and 15 patients (62.5%) demonstrated such communication on BH-CS-MRCP and BH-GRASE-MRCP, respectively. SNR, contrast ratio, and CNR of BH-CS-MRCP were higher than BH-GRASE-MRCP (p < 0.001). Both BH-CS-MRCP and BH-GRASE-MRCP are useful imaging methods with sufficient image quality. Each method has advantages, such as better visualization of small ducts with BH-CS-MRCP and greater time saving with BH-GRASE-MRCP. These differences allow diverse choices for visualization of the pancreaticobiliary tree in clinical practice.

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Effect of lung volume on breath holding

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.5.1962 ◽

1987 ◽

Vol 62 (5) ◽

pp. 1962-1969 ◽

Cited By ~ 22

Author(s):

W. A. Whitelaw ◽

B. McBride ◽

G. T. Ford

Keyword(s):

Lung Volume ◽

Hold Time ◽

Esophageal Pressure ◽

Breath Holding ◽

Breath Hold ◽

Pressure Waves ◽

Expiratory Muscle ◽

Inspiratory Muscles ◽

Consistent Change ◽

Rhythmic Contractions

The mechanism by which large lung volume lessens the discomfort of breath holding and prolongs breath-hold time was studied by analyzing the pressure waves made by diaphragm contractions during breath holds at various lung volumes. Subjects rebreathed a mixture of 8% CO2–92% O2 and commenced breath holding after reaching an alveolar plateau. At all volumes, regular rhythmic contractions of inspiratory muscles, followed by means of gastric and pleural pressures, increased in amplitude and frequency until the breakpoint. Expiratory muscle activity was more prominent in some subjects than others, and increased through each breath hold. Increasing lung volume caused a delay in onset and a decrease in frequency of contractions with no consistent change in duty cycle and a decline in magnitude of esophageal pressure swings that could be accounted for by force-length and geometric properties. The effect of lung volume on the timing of contractions most resembled that of a chest wall reflex and is consistent with the hypothesis that the contractions are a major source of dyspnea in breath holding.

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Effect of gravity on aerosol dispersion and deposition in the human lung after periods of breath holding

Journal of Applied Physiology ◽

10.1152/jappl.2000.89.5.1787 ◽

2000 ◽

Vol 89 (5) ◽

pp. 1787-1792 ◽

Cited By ~ 21

Author(s):

Chantal Darquenne ◽

Manuel Paiva ◽

G. Kim Prisk

Keyword(s):

Flow Rate ◽

Turbulent Mixing ◽

Direct Evidence ◽

Human Lung ◽

Hold Time ◽

Aerosol Deposition ◽

Breath Holding ◽

Breath Hold ◽

Constant Flow Rate ◽

Aerosol Dispersion

To determine the extent of the role that gravity plays in dispersion and deposition during breath holds, we performed aerosol bolus inhalations of 1-μm-diameter particles followed by breath holds of various lengths on four subjects on the ground (1G) and during short periods of microgravity (μG). Boluses of ∼70 ml were inhaled to penetration volumes (Vp) of 150 and 500 ml, at a constant flow rate of ∼0.45 l/s. Aerosol concentration and flow rate were continuously measured at the mouth. Aerosol deposition and dispersion were calculated from these data. Deposition was independent of breath-hold time at both Vp in μG, whereas, in 1G, deposition increased with increasing breath hold time. At Vp = 150 ml, dispersion was similar at both gravity levels and increased with breath hold time. At Vp = 500 ml, dispersion in 1G was always significantly higher than in μG. The data provide direct evidence that gravitational sedimentation is the main mechanism of deposition and dispersion during breath holds. The data also suggest that cardiogenic mixing and turbulent mixing contribute to deposition and dispersion at shallow Vp.

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Changing effect of lung volume on respiratory drive in man

Journal of Applied Physiology ◽

10.1152/jappl.1975.38.5.768 ◽

1975 ◽

Vol 38 (5) ◽

pp. 768-773 ◽

Cited By ~ 2

Author(s):

N. N. Stanley ◽

M. D. Altose ◽

S. G. Kelsen ◽

C. F. Ward ◽

N. S. Cherniack

Keyword(s):

Human Subjects ◽

Inhibitory Effect ◽

Breath Holding ◽

Breath Hold ◽

Respiratory Drive ◽

Lung Inflation ◽

Single Breath ◽

Single Breath Hold ◽

Sustained Effect ◽

Residual Capacity

Experiments were conducted on human subjects to study the effect of lung inflation during breath holding on respiratory drive. Two series of experiments were performed: the first to examine respiratory drive during a single breath hold, the second designed to examine the sustained effect of lung inflation on subsequent breath holds. The experiments involved breath holding begun either at the end of a normal expiration or after a maximum inspiration. When breath holding was repeated at 10-min intervals, the increase in BHT produced by lung inflation was greater in short breath holds (after CO2 rebreathing) than in long breath holds (after hyperventilation). If breath holds were made in rapid succession, the first breath hold was much longer when made at total lung capacity than at functional residual capacity, but this effect of lung inflation diminished in subsequent breath holds. It is concluded that the inhibitory effect of lung inflation decays during breath holding and is regained remarkably slowly during the period of breathing immediately after breath holding.

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Control of ventilation in elite synchronized swimmers

Journal of Applied Physiology ◽

10.1152/jappl.1987.63.3.1019 ◽

1987 ◽

Vol 63 (3) ◽

pp. 1019-1024 ◽

Cited By ~ 34

Author(s):

R. L. Bjurstrom ◽

R. B. Schoene

Keyword(s):

Heart Rate ◽

Ventilatory Response ◽

Minute Ventilation ◽

Mean Value ◽

Heart Rate Change ◽

Breath Holding ◽

Breath Hold ◽

Lung Volumes ◽

Co2 Partial Pressure ◽

Control Of Ventilation

Synchronized swimmers perform strenuous underwater exercise during prolonged breath holds. To investigate the role of the control of ventilation and lung volumes in these athletes, we studied the 10 members of the National Synchronized Swim Team including an olympic gold medalist and 10 age-matched controls. We evaluated static pulmonary function, hypoxic and hypercapnic ventilatory drives, and normoxic and hyperoxic breath holding. Synchronized swimmers had an increased total lung capacity and vital capacity compared with controls (P less than 0.005). The hypoxic ventilatory response (expressed as the hyperbolic shape parameter A) was lower in the synchronized swimmers than controls with a mean value of 29.2 +/- 2.6 (SE) and 65.6 +/- 7.1, respectively (P less than 0.001). The hypercapnic ventilatory response [expressed as S, minute ventilation (1/min)/alveolar CO2 partial pressure (Torr)] was no different between synchronized swimmers and controls. Breath-hold duration during normoxia was greater in the synchronized swimmers, with a mean value of 108.6 +/- 4.8 (SE) vs. 68.03 +/- 8.1 s in the controls (P less than 0.001). No difference was seen in hyperoxic breath-hold times between groups. During breath holding synchronized swimmers demonstrated marked apneic bradycardia expressed as either absolute or heart rate change from basal heart rate as opposed to the controls, in whom heart rate increased during breath holds. Therefore the results show that elite synchronized swimmers have increased lung volumes, blunted hypoxic ventilatory responses, and a marked apneic bradycardia that may provide physiological characteristics that offer a competitive advantage for championship performance.(ABSTRACT TRUNCATED AT 250 WORDS)

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Demonstration of airway closure in man

Journal of Applied Physiology ◽

10.1152/jappl.1975.38.6.1117 ◽

1975 ◽

Vol 38 (6) ◽

pp. 1117-1125 ◽

Cited By ~ 56

Author(s):

L. A. Engel ◽

A. Grassino ◽

N. R. Anthonisen

Keyword(s):

Chest Wall ◽

Pulmonary Circulation ◽

Gas Flow ◽

Regional Perfusion ◽

Breath Holding ◽

Breath Hold ◽

Gas Mixture ◽

Airway Closure ◽

Dependent Lung ◽

Compton Scatter

After partial equilibration of the lung with a N2O gas mixture absorption of N2O by the pulmonary circulation results in a flow of gas into the lungs during breath holding. A bolus of 133Xe introduced at the mouth at the beginning of the breath hold is carried in by the gas flow and distributed according to regional perfusion. In three subjects, breath holding at FRC, apex-to-base distribution of a 133Xe bolud delivered by N2O absorption (Xecar) was similar to that of a bolus injected intravenously (Xeiv). Near RV however, much less of Xecar penetrated into dependent zones than expected from the distribution of Xeiv. In fact, distribution of Xecar did not differ from that of a slowly inhaled bolus. Correction for Compton scatter in the chest wall, measured in one subject, accounted only in part for the radioactivity recorded over dependent lung regions. The findings indicate that near RV some but not all of the dependent airways must be closed. Furthermore, the distribution of airway closure completely accounts for the distribution of a bolus inhaled from RV.

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