Sleep apnea is a potentially serious sleep disorder in which breathing repeatedly stops and starts. If you snore loudly and feel tired even after a full night’s sleep, you might have sleep apnea.The main types of sleep apnea are:

Obstructive sleep apnea, the more common form that occurs when throat muscles relax

Central sleep apnea, which occurs when your brain doesn’t send proper signals to the muscles that control breathing

Complex sleep apnea syndrome,  also known as treatment-emergent central sleep apnea, which occurs when someone has both obstructive sleep apnea and central sleep apnea.

Reference: By Mayo Clinic Staff, https://www.mayoclinic.org/diseases-conditions/sleep-apnea/symptoms-causes/syc-20377631 , consulted on June 29th, 2019