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Results for “Breath Holding”

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At least 19 recordsLinked to original sources
PubMed1977

Effects of Valsalva and Mueller maneuvers on breath-holding time.

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.

Adaptation, Physiological↗
PubMed1978

The breathing pattern after breath-holding: the influence of chest position and the drive to breathe.

The pattern of breathing following the breaking-point of sixty breath-holds has been studied in five healthy adults and compared with the pattern during recovery from CO2-rebreathing. The volume and direction of the first respiratory movement, and the VT, V relation for the first four complete breaths was measured. Only when breath-holds were terminated with an inspiration was the accumulated drive to breathe reflected in an increased volume of the first respiratory movement: terminating expirations simply returned the chest to the resting respiratory level. The volume of the first inspiration was not influenced by the intervention of a terminating expiration, suggesting that expiratory movements do not dissipate the non-chemical component of the drive to breathe. In three of the five subjects the tidal volumes for given levels of ventilation were greater following breath-holding than following rebreathing. This altered pattern of breathing has been interpreted in terms of an insiratory-augmenting reflex.

Adult↗
PubMed1979

Diffusing capacity at different lung volumes during breath holding and rebreathing.

Single-breath diffusing capacity of the lung for carbon monoxide (DLCO) increases as lung volume increases above functional residual capacity (FRC). However, the physiological mechanism responsible for this increase remains controversial. This volume dependence of diffusing capacity could reflect changing regional distribution of inspired air as lung volume increases rather than a change in capillary blood volume or surface area for gas exchange. We measured DLCO during breath holding and during rebreathing with a technique employed to mix respired gases throughout the lung thereby minimizing regional distribution differences. Measurements were made 1,500 ml above FRC and near total lung capacity (TLC). Breath holding DLCO was 18% higher near TLC than at 1,500 ml above FRC (P less than 0.05). Rebreathing DLCO was 16% higher near TCL than at 1,500 ml above FRC (P less than 0.01). Equality of results by the two techniques indicates that changes in DLCO with lung volume are not a consequence of the changing distribution of inspired air. Our results are compatible with the hypothesis that effective surface area of the lung increases as lung volume expands.

Adult↗
PubMed2026

Adaptations to breath-hold diving: from traditional divers to elite athletes.

Breath-hold diving exposes humans to repeated episodes of profound hypoxia and hypercapnia, eliciting physiological adaptations that enable prolonged underwater performance. This article summarises current knowledge on chronic adaptations in elite breath-hold athletes and traditional diving populations, including the Bajau sea nomads of Southeast Asia and the Korean Haenyeo divers. Evidence indicates that repeated apnoea induces adaptations across multiple physiological systems. Haematological changes include increased spleen size and enhanced splenic contraction, augmenting circulating haemoglobin and oxygen stores during apnoea. In elite divers, structured training can increase resting spleen volume, whereas the Bajau exhibit genetically associated splenic enlargement linked to variants near the PDE10A gene. Cardiopulmonary adaptations include modified pulmonary vascular responses to hypoxia, improved oxygen conservation, and metabolic shifts favoring efficient mitochondrial energy production. Molecular adaptations involve enhanced antioxidant defenses and activation of hypoxia-responsive pathways that may mitigate oxidative stress associated with repeated hypoxia-reoxygenation cycles. Emerging evidence also suggests neural plasticity and possible structural brain adaptations, although the long-term neurological consequences of chronic intermittent hypoxia exposure remain uncertain. Studies of traditional diving populations indicate that both phenotypic plasticity and genetic selection contribute to diving capacity, highlighting interactions between training and evolution. Despite these benefits, breath-hold diving also carries risks, including hypoxic blackout, decompression sickness, and potential neurological injury. Understanding the mechanisms underlying human tolerance to extreme hypoxia may have implications beyond diving physiology, including applications in cardiovascular medicine, hypoxic diseases, and rehabilitation. Further longitudinal, genomic, and mechanistic studies are needed to clarify the limits, benefits, and clinical relevance of these adaptations.

Humans↗
PubMed1976

[Analysis of the imperative stimulus restricting voluntary breath holding].

In 5 healthy young men, the maximal voluntary breath holding--was studied under conditions of different initial values of PACO2--after oxygen inhalation at ordinary minute volume of respiration or at hyperventilation, or after breathing with oxygen mixtures with 2, 4, 6, 8 or 10% CO2. PACO2 was recorded at the moment of resuming of the intercostal muscles electric activity and at the point of breaking up the apnoea. A mathematical model was constructed. The hypothesis of participation of two independent factors (chemo- and mechanoreceptive) in genesis of the imperative stimulus for breathing was checked. The data obtained suggest that, in fact, the only factor restricting the duration of voluntary breath holding--is the summed up in time chemoreceptive stimulation. The involuntary contractions of respiratory muscles observed during apnoea are, apparently, a connecting link in formation of the imperative stimulus which breaks up the cessation of breathing.

Adult↗
PubMed1976

Role of the carotid bodies in the heart rate response to breath holding in man.

To investigate the role of the carotid bodies in regulating the bradycardia of breath holding in man, we studied heart rate (HR) responses to prolonged breath holding (BH) in five asymptomatic asthmatic patients whose carotid bodies had been resected (CBR). Seven normal subjects served as controls. BH experiments were randomly initiated with single breaths of 100%, 21%, or 12% 92. During BH with 21% O2, normal subjects displayed the typical bradycardia; this response, however, was attenuated with the other O2 concentrations. In contrast, the CBR subjects manifested BH tachycardia which was inversely proportional to the O2 tension. HR increased in be CBR group by 5%, 31%, and 45% during BH with 100%, 21%, and 12% O2, respectively. These results demonstrate that the bradycardia of BH in normal man is under the influence of the carotid bodies. During BH and in the absence of carotid bodies, an O2 tension-dependent tachycardia is unveiled.

Adult↗
PubMed1978

Post-operative apnoea caused by breath-holding spells.

After recovery from anaesthesia for a urological procedure a two-and-a-half-year-old child with a history of breath-holding spells became apnoeic and cyanotic in the immediate post-operative period. The pathophysiology of breath-holding as the cause of the apnoea is discussed. Management includes ventilation with oxygen and avoidance of inappropriate treatment with drugs to reverse muscle relaxants or narcotic anesthetics.

Apnea↗
PubMed1978

Reflex anoxic seizures ('white breath-holding'): nonepileptic vagal attacks.

From clinical history 58 children were diagnosed as having reflex anoxic seizures secondary to provoked cardioinhibition (also known as white breath-holding attacks). Before referral, these seizures were commonly misdiagnosed as epileptic either because the provocation was ignored, not recognised, or was a febrile illness, or because there was no crying, no obvious breath-holding, little cyanosis, and often no pallor to suggest syncope and cerebral ischaemia. The duration of cardiac asystole after ocular compression was measured in these children and in 60 additional children with other paroxysmal disorders. In 45 (78%) of the 58 with reflex anoxic seizures asystole was 2 seconds or over, and in 32 (55%) it was 4 seconds or greater, an abnormal response. Review of the literature supports the concept that these seizures result from vagal-mediated reflex cardiac arrest which can if necessary be prevented by atropine. The simple name 'vagal attack' is proposed. Ocular compression under EEG and ECG control supports the clinical diagnosis if asystole and/or an anoxic seizure is induced; the procedure described is safe and should be routine in seizure or syncope evaluation, when a meticulous history still leaves room for doubt.

Adolescent↗
PubMed1979

Dco at various breath-holding times: comparison in patients with chronic bronchial asthma and emphysema.

Measurement of Dco is known to be dependent upon functional inhomogeneities. Because different types of inhomogeneities are operative in patients with bronchial asthma and patients with emphysema, different changes of Dco with increasing breath-holding time, tA, are to be expected. We studied the change of Dco with increasing breath-holding time in healthy subjects, patients with asthma bronchiale and patients with emphysema. In the patients the severity of airway obstruction was about the same. The following results were obtained: (a) in healthy subjects and in the asthmatics Dco decreased with tA, in a similar manner, approaching a value (ml . min-1 . Terror-1) of 34.7 and 31.6 at 10 sec, respectively, and (b) in patients with emphysema Dco increased with tA, yielding negative values at small tA: 1.5 sec-23.4; 10 sec: 11.7. From these results we suggest that in healthy subjects and in patients with bronchial asthma parallel inhomogeneities influence the course of Dco. In emphysema the time couse of Dco is best explained with a faster intrapulmonary mixing of He compared to CO. This behavior indicates that in emphysema low Dco values can be mainly attributed to large diffusional resistances (stratification) within the lungs.

Adult↗
PubMed1977

Heart rate response to breath holding at 18.6 ATA.

The heart rate (HR) responses to breath-holding (BH) with the without face immersion (FI) in 31 or 27 degrees C water was studied in 1 ATA air and hyperbaric He-O2 environments in 4 male subjects during a dry saturation dive to simulated depth of 580 ft (18.6 ATA). When a 60 sec BH or FI was performed while leaning forward, there was a significant linear correlation between the maximal bradycardial response (delta HRmax) and ambient pressure for simple BH (r-0.08, P less than 0.05) and 31 degrees C FI (r = 0.91, P less than 0.01), but not for 27 degrees C FI. A similar trend was seen during 30 sec BH's while seated erect. The facial cold-dependent component of the FI bradycardia was not significantly altered by pressure. In general, there were significant correlations between the initial HR and the initial thoracic conductive volume (TCV; measured by the four-electrode Minnesota impedance cardiograph), and between the initial TCV and delta HRmax observed during seated erect BH's. Since the TCV was generally higher at depth, it is suggested that a mechanical effect due to increased TCV at depth, possibly related to increased gas density, is at least partly responsible for the pressure dependence of BH bradycardia.

Atmospheric Pressure↗
PubMed1978

The effect of breath holding, hyperventilation, and exercise on nasal resistance.

A group of 51 patients was studied by a technique of active posterior rhinomanometry that assessed the influence of breath holding, hyperventilation, and exercise on nasal resistance. Breath hodling of 30 seconds or longer produced a decrease in nasal resistance in most of the subjects tested. Hyperventilation had variable effects on nasal resistance, and exercise consistently decreased nasal resistance. These observations are consistent with the proposed effect of chemoreceptor stimulation on nasal airway resistance.

Adolescent↗
PubMed1979

[Propagation of error, sensitivity and specificity of the CO gas transfer in various breath holding and steady state methods (author's transl)].

For determining DL/VA or the Krogh factor use of the breath-holding CO method only is recommended because it is relatively free from errors, independent of distribution and is relatively specific regarding diffusion. The steady state methods tend to be unspecific despite calculation of DL/VA and to be rather sensitive to uneven distribution of ventilation.

Asthma↗
PubMed1978

Computed tomography of solitary pulmonary nodules: experience with scanning times longer than breath-holding.

Thirty-one patients with solitary pulmonary nodules--18 benign and 13 malignant--proven by either tissue diagnosis or prolonged follow-up were evaluated by computed tomography (CT). A device (ACTA scanner 0100) with scanning times greater than breath-holding was used with full understanding of its related limitations. A retrospective study of the CT features of these nodules led us to establish several criteria for benign nodules. CT evidence of calcium is felt to be the most important feature of benignancy. In the absence of calcium, irregular nodule margins, perinodular fibrosis, satellite nodules, and pleural thickening opposite a peripherally situated nodule are helpful to suggest its benign nature.

Humans↗
PubMed1979

[The mixing index in the argon breath holding test for the demonstration of pharmacologically induced airways reactions. A comparison with other methods (author's transl)].

In 42 patients with obstructive airways diseases the behavior of the mixing index (delta argon %/1 during phase III of the argon-volume diagram) was studied after beta2 stimulation or after provocation by acetylcholine. Changes in airways resistance resp. conductance (GAW), FEV1.0 and residual volume (RV) were also determined for comparison. In an inhomogeneous subgroup with obstructive airways disease of various aetiology the mixing index (MI) and FEV1.0 indicated changes in the airways system with about equal frequency. Distinct discrepancies between the two tests, observed in a few cases, suggest that the two methods register different pathophysiological reactions. These differences could be confirmed statistically in a more homogeneous subgroup with extrinsic bronchial asthma. A correlation could be established between MI and RV on the one hand and between FEV1.0 or GAW and RV on the other hand. The results indicate that the mixing index as a test of distribution of ventilation reflects mainly the reactions of the small airways. Its use offers the possibility of a more differentiated pharmacodynamic evaluation.

Acetylcholine↗