Nocturnal worsening of asthma and sleep-disordered breathing

Asthma has a tendency to destabilize and get worse at night, probably due to a nocturnal increase in airway inflammation and bronchial responsiveness. Nocturnal airway narrowing in asthma is often associated with sleep disorders, such as episodes of nocturnal and early morning awakening, difficulty, in maintaining sleep, and daytime sleepiness. On the other hand, ail association has been documented between nocturnal sleep-disordered breathing and asthma. This review highlights the causes of nocturnal worsening of asthma and examines the evidence pointing toward a causal relationship between nocturnal asthma and sleep-disordered breathing.