PND tends to occur within a few hours after you’ve fallen asleep. It wakes you up. You might gasp for air, cough, or sit or stand up to try to open your airways. After a while, your breathing may return to normal. It might take a half an hour, or sometimes longer, to recover. Many people find it difficult to return to sleep after an episode of PND. PND can be distressing, and one or more episodes may lead to sleep anxiety or even insomnia. If sitting or standing up doesn’t relieve symptoms of PND, you should call for emergency medical assistance right away