Obstructive sleep apnea is a disorder that causes the airways to collapse or block while you're asleep. It can cause brief episodes of not breathing, numerous times throughout each night. But many people don't know they have it! Check out for these early warning signs of sleep apnea. Being a leading sleep apnea clinic, we have noted down the early signs of sleep apnea. The symptoms often occur without any warning. If your partner wakes up abruptly then chances are their sleep is disrupted by an obstruction(s).