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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(More)
We assessed the effect of inspiratory loaded breathing (ILB) on respiratory muscle strength and investigated the extent to which respiratory muscle fatigue is associated with chest wall volume changes during ILB. Twelve healthy subjects performed ILB at 76 ± 11% of maximal inspiratory mouth pressure (MIP) for 1h. MIP and breathing pattern during 3 min of(More)
Breath-by-breath (BbB) oxygen uptake rate (V(O)(2)) was measured at the mouth (MO) and at the alveolar level, at the onset of square wave cycling exercise of moderate intensity in six healthy male subjects. Alveolar BbB V(O)(2) values were calculated correcting MO V(O)(2) values by (i) estimating (GR); and (ii) measuring (opto-electronic plethysmography,(More)
This short review summarizes how lung and chest wall mechanics can be modelled and which are the mechanical constraints imposed on the ventilatory system and its components during exercise. In healthy humans the structural and functional characteristics of the ventilator pump are able to meet the increased demands of ventilation during exercise and it is(More)
We compared the rate of perceived exertion for respiratory (RPE,resp) and leg (RPE,legs) muscles, using a 10-point Borg scale, to their specific power outputs in 10 healthy male subjects during incremental cycle exercise at sea level (SL) and high altitude (HA, 4559 m). Respiratory power output was calculated from breath-by-breath esophageal pressure and(More)
Expulsive maneuvers (EMs) caused by simultaneous contraction of diaphragm and abdominal muscles shift substantial quantities of blood from the splanchnic circulation to the extremities. This suggests that the diaphragm assisted by abdominal muscles might accomplish ventilation and circulation simultaneously by repeated EMs. We tested this hypothesis in(More)
Assessment of the presence and severity of acute mountain sickness (AMS) is based on subjective reporting of the sensation of symptoms. The Lake Louise symptom scoring system (LLS) uses categorical variables to rate the intensity of AMS-related symptoms (headache, gastrointestinal distress, dizziness, fatigue, sleep quality) on 4-point ordinal scales; the(More)
Paradoxical inward displacement of the costal margin during inspiration is observed in many chronic obstructive pulmonary disease patients at rest but its importance is unclear. The current authors studied 20 patients (forced expiratory volume in one second 32.6+/-11.7, functional residual capacity 186+/-32% predicted) and 10 healthy controls at rest and(More)
Were evaluated individuals divided into two groups: we studied chronic heart failure (CHF) (19 patients with CHF plus cardiomegaly) and control (12 healthy volunteers) during performance of inspiratory loaded breathing (ILB). We evaluated: spirometry, functional capacity through the six-minute walk test (6MWT), and distribution of thoracoabdominal volumes(More)
In order to investigate underlying mechanisms, the present authors studied the effect of pulmonary rehabilitation on the regulation of total chest wall and compartmental (ribcage, abdominal) volumes during exercise in patients with chronic obstructive pulmonary disease. In total, 20 patients (forced expiratory volume in one second, mean +/- SEM 39 +/- 3%(More)