We explored the locomotor respiratory coupling (LRC) during a 50-min constant-load submaximal cycling exercise. A 4-week recombinant human erythropoietin (r-HuEPO) treatment improved participants' aerobic capabilities, but did not elicit significant changes in LRC. The distributions of the respiratory frequency over pedalling frequency ratios were systematically bimodal, with a preferred use ...

Rehabilitation including physiotherapy is an important part of the treatment used to help improve the quality of life of patients with cystic fibrosis (CF). The aim of this study was to determine the value of the breath-hold time as an index of exercise tolerance in patients with CF. Eighteen patients ...

Breath holding maneuvers induce hypoxia, hypercapnia, and various cardiovascular responses typically including increases in total peripheral resistance, mean arterial pressure (MAP) and decreases in heart rate (HR). During dynamic exercise these responses may have a generally negative impact on performance. Moreover, they deserve particular attention in cardiovascular risk subjects. In ...

The objective of this study was to determine the effects of breathing type and body position on sternocleidomastoid and suprahyoid electromyographic (EMG) activity. The sample included 18 subjects with upper costal breathing type (study group) and 15 subjects with costo-diaphragmatic breathing type (control group). All individuals had natural dentition and ...

The present study analyzes the respiratory responses of the neotropical air-breathing fish Hoplosternum littorale to graded hypoxia and increased sulfide concentrations. The oxygen uptake (VO2), critical O2 tension (PcO2), respiratory (fR) and air-breathing (fRA) frequencies in response to graded hypoxia were determined for fish acclimated to 28 degrees C. H. ...

The diving response elicited by breath-holding (BH) and immersion mainly consists of bradycardia, decreased cardiac output, and peripheral vasoconstriction. These responses reduce oxygen consumption and thereby prolong the duration of the dive. They may also lead to cardiac arrhythmias or hypoxia, however, which in turn may play a role in ...

To assess the stability and reproducibility of different breath-hold levels in healthy volunteers and patients using dynamic MRI (dMRI). In ten healthy volunteers and ten patients with pulmonary hypertension (PH) and normal lung function craniocaudal intrathoracic distances (CCD) were measured during inspiratory and expiratory breath-hold (15 s) (in healthy volunteers ...

The impact of meditation on cardiorespiratory synchronization with respect to breathing oscillations and the modulations of heart rate induced by respiration (respiratory sinus arrhythmia, RSA) was investigated in this study. Four different exercises (spontaneous breathing, mental task, Zen meditation, and Kinhin meditation) were consecutively performed by nine subjects mainly without ...

The aim of this study was to investigate metabolic demand and mechanical work of different basketball wheelchairs that represented significant stages of its evolution from 1960 to date. Four subjects pushed each model on a basketball court at different speeds (from 0.90 to 2.35 m.s(-1)). During the trials, oxygen consumption ...

We determined the argon (Ar) isotope ratio in samples of expired alveolar gas gathered during Ar washout from residual gas relative to this ratio in samples of expired alveolar gas gathered just before the beginning of this washout in 13 young, healthy human subjects at rest. These data were determined ...

This research tests the relative ability of body size factors and sex to explain variation in nose volume and to explain metabolic measures during rest and moderate exercise in 50 young adults. It uses standard anthropometric measures plus two new measures of nose morphology (nose/face angle and nose volume) and ...

BACKGROUND: The power of breathing (PoB) is used to estimate the mechanical workload of the respiratory system. Aim of this study was to investigate the effect of different tidal volume-respiratory rate combinations on the PoB when the elastic load is constant. In order to assure strict control of the experimental ...

Breath-holding induces cardiovascular responses, notably bradycardia and peripheral vasoconstriction, which are known collectively as the diving response. This response is oxygen-conserving, i.e. an augmented response attenuates arterial oxygen desaturation, and is enhanced by apnoea training. To test this hypothesis, we compared heart rate (HR) and arterial oxygen saturation (SaO (2)) ...

The objective of this study was to evaluate the effects of lung perfusion on the slopes of phases II (S(II)) and III (S(III)) of a single-breath test of CO(2) (SBT-CO(2)). Fourteen patients submitted to cardiac surgery were studied during weaning from cardiopulmonary bypass (CPB). Pump flow was decreased in 20% ...

Processes controlling aroma release and delivery during and after the consumption of a beverage were studied using real-time physiological and aroma release measurements. The key processes were as follows. During swallowing, a portion of the buccal gas phase was transferred first to the throat and then to the nasal passages ...

PURPOSE: To evaluate whether prostaglandins are mediators of the hypercapnia-associated vasodilation of the optic nerve head vessels. METHODS: We measured the PO(2) at intervascular areas of the optic disc in 9 anaesthetized miniature pigs using oxygen-sensitive microelectrodes placed at <50 mum from the optic disc. PO(2) was measured continuously under ...

BACKGROUND: The exercise pressor reflex is thought to be an important cardiovascular control mechanism that may be compromised in disease states such as congestive heart failure and other metabolic syndromes. The purpose was to describe the exercise pressor reflex by observing heart rate variability and blood pressure responses to handgrip-exercise ...

Endotracheal tubes (ETTs) are used to establish airway access in patients with ventilatory failure and during general anaesthesia. Tube malpositioning can compromise respiratory function and can be associated with increased morbidity and mortality. Clinical assessment of ETT position normally involves chest auscultation, which is highly skill-dependent and can be misleading. ...

We hypothesized that the perfusion heterogeneity in the human, upright lung is determined by nongravitational more than gravitational factors. Twelve and six subjects were studied during two series of parabolic flights. We used cardiogenic oscillations of O(2)/SF(6) as an indirect estimate of intraregional perfusion heterogeneity (series 1) and phase IV ...

In cattle, sheep and goats, during resting conditions, breathing frequency (f) greatly exceeds the value expected for their body weight (W, kg) from the allometric curve of other land mammals. It was postulated that this was the effect of the production of CO2 during rumen fermentation. If this were the ...

To test the hypothesis that the fractal character of breathing and heart rate are independent, inter-breath intervals (IBI) and R-R intervals (RRI) were measured during rest and two levels of exercise at 1 and 2.8 ATA in a hyperbaric chamber in 18 male and female subjects (ages 19-74 years). Both ...

OBJECTIVE: Acute anemia slows the responses to clinical tests of cognitive function. We tested the hypothesis that these slowed responses during acute severe isovolemic anemia in healthy unmedicated humans result from impaired central processing. METHODS: A blinded operator measured the latency of the P300 peak in nine healthy volunteers at ...

Increased wakefulness is known to suppress the initial ventilatory response to passive movement and the steady-state ventilatory response to exercise. However, the effect of increased wakefulness upon the integrated ventilatory response at the onset of exercise is not known. We hypothesized that increasing wakefulness via a cognitive task would attenuate ...

BACKGROUND: We have observed that dosimeter-run nebulizers have a much smaller output when manually activated than when breath activated; however, this has not been adequately investigated. OBJECTIVE: To evaluate the effect of different calibration methods on nebulizer output. METHODS: Six healthy subjects performed all calibrations. The nebulizers were operated by ...

OBJECTIVES: Carboxyhemoglobin (COHb) levels can be estimated by chemical analysis of exhaled alveolar breath. Such noninvasive measurement could be used on the fireground to screen both firefighters (FFs) and victims. The purpose of this study was to assess the feasibility of using a hand-held carbon monoxide (CO) monitoring device to ...

Inhaled Nitric oxide is a selective and potent pulmonary vasodilator with minimal influence on systemic vascular resistance. Due to these properties NO becomes widespread treatment for pulmonary hypertension of different etiologies. However, during inhalation via inspiratory limb of breathing circuit NO reacts with oxygen, producing nitrogen dioxide (NO2) which is ...

BACKGROUND: Current international resuscitation guidelines for lay people rely on the assessment of "normal breathing" as a key sign of breathing and circulation. However, it is not known how accurately laypersons can discriminate between "normal" and "abnormal" breathing. The aim of this study was to test the ability of medical ...

OBJECTIVE: The purpose of this study is to determine the accuracy of retrospective estimated blood alcohol concentrations (eBACs) for re-creating intoxication resulting from a naturally occurring drinking event. This study identified five eBAC equations, applied them to self-report data and compared the results to actual blood alcohol concentration obtained by ...

BACKGROUND: Diarrhea is a common problem in critically ill patients. Our patients are fed a high-carbohydrate enteral formula. We hypothesized that diarrhea in our patients may be related to the osmotic effects of unabsorbed carbohydrate in the small intestine and colon. METHODS: We studied 19 patients, 3 months to 17 ...

The purpose of this study was to examine the relationship between the intra-cycle variation of the horizontal velocity of displacement (dV) and the energy cost (EC) in butterfly stroke. Five Portuguese national level swimmers performed one maximal and two sub-maximal 200-m butterfly swims. The oxygen consumption was measured breath-by-breath by ...

Hyperventilation prior to breath-hold diving increases the risk of syncope as a result of hypoxia. Recently, a number of cases of near-drownings in which the swimmers did not hyperventilate before breath-hold diving have come to our attention. These individuals had engaged in prolonged exercise prior to breath-hold diving and it ...

The effects of breathing depth in attenuating induced bronchoconstriction were studied in 12 healthy subjects. On four separate, randomized occasions, the depth of a series of five breaths taken soon (approximately 1 min) after methacholine (MCh) inhalation was varied from spontaneous tidal volume to lung volumes terminating at approximately 80, ...

Idiopathic hyperventilation (IH) is a condition of uncertain aetiology characterized by sustained arterial and alveolar hypocapnia and a plethora of symptoms, the most commonly reported being shortness of breath, and breathlessness. We previously reported that anxiety increases respiratory frequency and minute ventilation with no change in metabolism in normal subjects. ...

This study examined the role of phasic pulmonary stretch receptor (PSR) feedback in ventilatory control, breath clustering and breath timing in decerebrate, paralysed and artificially-ventilated cane toads (Bufo marinus) under conditions designed to minimise tonic PSR feedback. Fictive breathing was recorded as trigeminal motor output to the buccal musculature. Artificial ...

The evolution of air-breathing organs (ABOs) is associated not only with hypoxic environments but also with activity. This investigation examines the effects of hypoxia and exercise on the partitioning of aquatic and aerial oxygen uptake in the Pacific tarpon. The two-species cosmopolitan genus Megalops is unique among teleosts in using ...

Arm work, by limiting movement of the chest wall and use of the respiratory muscles, may alter breathing pattern and gas exchange sufficiently to interfere with the ability to perform certain tasks. To determine the effects of arm work on breathing pattern during a well-controlled work task, depth of breathing, ...

The present study investigated the respiratory rates, frequency of air breathing and ability to extract oxygen from air compared to body mass of three neotropical air-breathing fishes (Lepidosiren paradoxa, Hoplerythrinus unitaeniatus and Hoplosternum littorale) with different accessory organs, under the same conditions of hypoxia (PO(2)<5 mm Hg) and temperature (25 ...

Body sway was studied in standing with eyes closed during quiet breathing and apnoea. The hypothesis was that absence of ventilation improved balance. Performance and control of balance were assessed by centre of gravity and centre of pressure motions respectively. Eight healthy male subjects participated in the study. The analysis ...

Practice of breathing exercises like pranayama is known to improve autonomic function by changing sympathetic or parasympathetic activity. Therefore, in the present study the effect of breathing exercises on autonomic functions was performed in young volunteers in the age group of 17-19 yr. A total of 60 male undergraduate medical ...

We report a study on the cavity ringdown spectroscopy of acetone in both the ultraviolet (UV) and the near-infrared (NIR) spectral regions to explore the potential for development of a breath analyzer for disease diagnostics. The ringdown spectrum of acetone in the UV (282.4-285.0 nm) region is recorded and the ...

OBJECTIVE: This study was designed to quantify and compare the instantaneous heart rate dynamics and cardiopulmonary interactions during sequential performance of three meditation protocols with different breathing patterns. BACKGROUND: We analyzed beat-to-beat heart rate and continuous breathing signals from 10 experienced meditators (4 females; 6 males; mean age 42 years; ...

STUDY OBJECTIVES: The degree to which physical exercise habits are related to sleep-disordered breathing is not known. We sought to investigate the association between a single-item exercise question and laboratory-assessed sleep-disordered breathing. DESIGN: A population-based cross-sectional epidemiologic study of adults measured the association between exercise and sleep-disordered breathing. Hours of ...

To identify the effect of normal breathlessness sensation elicited during intense intermittent exercise at exhaustion on limitation of exercise maintenance (Ex), the contribution of the flow-resistive unloading effect of normoxic helium-oxygen breathing on the breathlessness sensation to the change in the Ex was examined. Seven men repeatedly performed 12-s exercise ...

We reasoned that, if the lung inflation reflex contributes importantly to apnea-induced sympathetic activation, such activation would be attenuated in bilateral lung transplant recipients (LTX). We measured muscle sympathetic nerve activity (MSNA; intraneural electrodes), heart rate, mean arterial pressure, tidal volume, end-tidal Pco(2), and arterial oxygen saturation in seven LTX ...

The objective of this study was to investigate the synchronization between low-frequency breathing patterns and respiratory sinus arrhythmia (RSA) of heart rate during guided recitation of poetry, i.e., recitation of hexameter verse from ancient Greek literature performed in a therapeutic setting. Twenty healthy volunteers performed three different types of exercises ...

Baroreflex sensitivity is becoming an important clinical measurement. Nevertheless there is no recommend standard measurement protocol. This study assessed the ability of eight protocols to induce regular changes in cardiac beat-to-beat interval and systolic pressure (SP), and the effect each protocol had on baroreflex sensitivity (BRS). Twelve subjects had changes ...

OBJECTIVE: To investigate whether the cardiac R-R interval variation (RRIV) is of value in differentiating patients with Parkinson's disease (PD) from multiple system atrophy (MSA). BACKGROUND: RRIV assessment is a simple procedure, reflecting mainly vagal efferent activity. Reduced RRIV was reported in MSA. METHODS: RRIV at rest and after 120 ...

BACKGROUND: Only a few methods for the measurement of breathing are non-invasive and do not interfere with measured parameters. The static-charge-sensitive bed (SCSB) could be such a monitor. The aim of this study was to evaluate the validity of the SCSB compared with the respiratory inductive plethysmograph (RIP) using a ...

Expiratory flow limitation (EFL) during tidal breathing is a major determinant of dynamic hyperinflation and exercise limitation in chronic obstructive pulmonary disease (COPD). Current methods of detecting this are either invasive or unsuited to following changes breath-by-breath. It was hypothesised that tidal flow limitation would substantially reduce the total respiratory ...

The purpose of this study was to investigate the validity of the MetaMax II portable metabolic measurement system against the Douglas Bag technique. Nine recreationally active male subjects were included in a validation at 100 W, 10 well-trained male subjects at 200 W and 10 well-trained males at 250 W ...