People with asthma often suffer their worst symptoms at night which can lead to sleep problems and daytime sleepiness. Michigan researchers evaluated 115 adult asthma sufferers for sleepiness, obstructive sleep apnea (OSA), asthma severity and other medical problems and medications. They found that 55% being sleepy, 86% snoring, 38% reported habitually snoring. They also found that sleepiness was correlated with OSA and male gender, but not with asthma severity.
Teodorescu M et al. Sleep Med. 2006 Dec;7(8):607-13. Epub 2006 Jul 3