Normally it takes people about 60 to 90 minutes to reach REM sleep so they wouldnt enter this stage during a 20 minute nap. People with narcolepsy often enter REM sleep soon after falling asleep. If a person enters REM sleep in two or more of the five naps in eight minutes or less during the study its highly suggestive of narcolepsy.
Our love was covered in fur yet I was the only one who wanted to pet it.