Greater public education on sleep apnea helps people recognize sleep apnea symptoms earlier and receive preventative care. Sleep apnea is a chronic sleep disorder. There are three types of sleep apnea: obstructive sleep apnea (OSA), central sleep apnea, and mixed. Central sleep apnea happens when the brain stops sending signals to breathe, while mixed sleep apnea is a combination of both central and obstructive. Sleep apnea is one of the most common sleep disorders.