Sleep Facts

Sleep paralysis is the scary experience when you are consciously awake and aware while your body is still paralyzed from REM sleep. Frequently hallucinations and nightmares are a part of it, as well as a tightening of the chest, idiomatically, a "demon on your chest." While anyone can get sleep paralysis, it correlates with narcolepsy and sleep apnea. 

Source

(As for the picture, dogs can suffer from narcolepsy as well and dogs have been used in studies centered around narcolepsy.) 

I should have clarified! Sleep latency is usually measured with MSLT or the Multiple Sleep Latency Test. Every few hours, the subject has to try to sleep and the time it takes for them is timed; however if it goes over 20 minutes, then the test is terminated. If it takes you an hour to sleep, I'm guessing it's all about context-you might have high levels of alertness when you go usually go to bed, or maybe a sign of something serious, or perhaps it doesn't take as long as you think it does. Time can go slow when you're lying down in the dark not doing much of anything!