Sleep, respiratory physiology, and nocturnal asthma.
The nocturnal worsening of asthma is a common feature of this disease that recently has received extensive investigation. Most recent efforts have focused on the role of circadian biorhythms that could promote a nocturnal increase in airway inflammation, leading to a subsequent increase in airflow obstruction and asthma symptoms. However, definitive studies remain lacking. As discussed in this review, there is also substantial evidence that sleep itself may play a direct role in the nocturnal worsening of asthma. Potential mechanisms for such a sleep-related effect could include the supine posture, alterations in sympathetic and parasympathetic "balance," sleep-associated reductions in lung volume, intrapulmonary pooling of blood, and sleep-associated upper airway narrowing, both with and without snoring and obstructive sleep apnea (OSA). These potential contributors to this troublesome phenomenon deserve further consideration when investigating mechanisms of nocturnal asthma.
Ballard
R D
RD
National Jewish Medical and Research Center, University of Colorado Health Sciences Center, Denver 80206, USA.
D000403:Airway Resistance; D001249:Asthma / Q000209:etiology / Q000503:physiopathology*; D001810:Blood Volume; D002940:Circadian Rhythm; D006801:Humans; D008176:Lung Volume Measurements; D011652:Pulmonary Circulation; D012143:Respiratory Physiological Phenomena; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology; D012913:Snoring / Q000503:physiopathology