In contrast, Manser says, a person's passive vocabulary consists of the words whose meanings they knowâso that they do not have to look the words up in a dictionaryâbut which they would not necessarily use in ordinary conversation or writing (The Penguin Writer's Manual, 2004).
Sleep Apnea, Night Terrors, and Nightmares. Sleep apnea may also be to blame for your nightmares. During sleep apnea, your brain senses the low oxygen and realizes that you are under a very real threatâyou are being choked or smothered by your own bodyâand if nothing is done you will die.
4. Sleep apnoea. Sleep apnoea is a condition where your throat narrows or closes during sleep and repeatedly interrupts your breathing. This results in bad snoring and a drop in your blood's oxygen levels. The difficulty in breathing means you wake up often in the night and feel exhausted the next day.