Activity of respiratory pump and upper airway muscles during sleep onset

Ventilationdecreases at sleep onset. This change is initiated abruptly at -electroencephalographic transitions. The aim of this study was todetermine the contributions of reduced activity in respiratory pumpmuscles and upper airway dilator muscles to this change. Surfaceelectromyograms over the diaphragm (Di) and intercostal muscles andfine-wire intramuscular electrodes in genioglossus (GG) and tensorpalatini (TP) muscles were recorded in nine healthy young men. It wasshown that phasic Di and both phasic and tonic TP activities were lowerduring  than during  activity. Breath-by-breath analysis of thechanges at - transitions during the sleep-onset period showed anumber of changes. At - transitions, phasic activity of Di,intercostal, and GG muscles fell and rose again, and phasic and tonicactivities of TP fell and remained at low levels during . With astate transition from  to , the phasic and tonic activities ofthe Di, GG, and TP increased dramatically. It is now clear that thefall in ventilation that occurs with sleep is related to a fall inactivities of both upper airway dilator muscles and respiratory pumpmuscles.

     

Cardiac and respiratory activity at arousal from sleep under controlled ventilation conditions.

Arousal from sleep is associated with elevated cardiac and respiratory activity. It is unclear whether this occurs because of homeostatic mechanisms or a reflex activation response associated with arousal. Cardiorespiratory activity was measured during spontaneous arousals from sleep in subjects breathing passively on a ventilator. Under such conditions, homeostatic mechanisms are eliminated. Ventilation, end-tidal PCO2, mask pressure, diaphragmatic electromyograph, heart rate, and blood pressure were measured in four normal subjects under two conditions: assisted ventilation and a normal ventilation control condition. In the control condition, there was a normal, sleep-related fall in ventilation and rise in end-tidal PCO2. Subsequently, at an arousal, there was an increase in respiratory and cardiac activity. In the ventilator condition, a vigorous cardiorespiratory response to a spontaneous arousal from sleep remained. These results indicate that sleep-related respiratory stimuli are not necessary for the occurrence of elevated cardiorespiratory activity at an arousal from sleep and are consistent with the hypothesis that such activity is at least in part due to a reflex activation response.     

Cross-sectional examination of gender differences in depression and anxiety symptoms in patients with obstructive sleep apnea

Sleep and Biological Rhythms - This study examined the prevalence of depression and anxiety symptoms in OSA patients, and predictors of mood disturbance in male and female patients....     

Effect of age on sleep onset-related changes in respiratory pump and upper airway muscle function.

In normal young men, there is an abrupt fall in ventilation (VE), a rise in upper airway resistance (UAR), and falls in the activities of the diaphragm (Di), intercostals (IC), genioglossus (GG), and tensor palatini (TP) at sleep onset. On waking, there is an abrupt increase in VE and fall in UAR and an increase in the activities of Di, IC, GG, and TP. The aim of this study was to determine whether these changes are age dependent. Nine men aged 20 to 25 yr were compared with nine men aged 42 to 67 yr. Airflow, UAR, Di, and IC surface electromyograms (EMGs) and the intramuscular EMGs of GG and TP were recorded. It was found that the falls in IC, GG, and TP at the transition from alpha to theta electroencephalogram (EEG) activity were significantly greater in the older than in the younger men (P < 0.05) and that the fall in Di was also greater, although this was only marginally significant (P = 0.15). The rise in GG at theta-to-alpha transitions was also greater in the older than in the younger men, and there was a trend for TP to be higher.