1. The effects of mechanical stimulation in the nose, epipharynx, laryngopharynx and tracheobronchial tree, and of chemical irritation of the nasal mucosa, were studied on various somatic and autonomic functions in cats.2. Action potentials were recorded from the diaphragm and rectus abdominis muscles of spontaneously breathing cats, and from the phrenic and lumbar nerves of paralysed, artifici...

Factors influencing nasal versus oral breathing in asthmatics are not well understood. The current authors hypothesised that asthmatic subjects have enhanced perception of nasal threshold loads, and switch from nasal to oral breathing at a lower load than healthy subjects. In total, 15 mild asthmatic and 20 healthy control subjects breathed nasally via an inspiratory threshold loading device. N...

The purpose of this study was to evaluate sternocleidomastoideus (SCM) and trapezius (superior fibers) muscle activity patterns in mouth-breathing children, and to compare them with nasal-breathing children. Forty-six children, of both sexes, ranging from 8 to 12 years old, were evaluated through electromyography. The selected children were divided into two groups; Group I, was made up of 26 mo...

Oral breathing superficially dehydrates the airway lumen by decreasing the depth of the sol layer in humans and animals. Conversely, nasal breathing can increase the humidity of inspired air. We compared the effects of short-term oral and nasal breathing on Pth and perceived vocal effort in 20 female subjects randomly assigned to two groups: oral breathing (N = 10, age 21-32 years); nasal breat...

The purpose of this study was to assess the effects of quantitatively determined breathing patterns on dentofacial development in growing children. Forty-nine subjects ranging in age from 10 to 16 years participated in the breathing pattern assessment portion of this project. Oral, nasal, and total airflow were measured at separate times by means of a head-out body plethysmograph technique and ...

Healthy subjects with normal nasal resistance breathe almost exclusively through the nose during sleep. This study tested the hypothesis that a mechanical advantage might explain this preponderance of nasal over oral breathing during sleep. A randomised, single-blind, crossover design was used to compare upper airway resistance during sleep in the nasal and oral breathing conditions in 12 (seve...

Cardiopulmonary reflexes elicited by capsaicin (CAPS) instilled into the nasal passages were determined in 6 anesthetized dogs breathing spontaneously. Nasal instillation of CAPS (10 microg/ml, 10 ml) induced: 1) apneic response characterized by an increase in expiration time; 2) bronchoconstrictor response characterized by an increase in lung resistance and a decrease in dynamic compliance; an...