James has been sleeping for about 90 minutes when his brain shows rapid, irregular waves. His blood pressure rises, his heart rate increases, and his skeletal muscles go limp. Which of the following is the most likely conclusion?
A) James is chronically sleep-deprived and his sleep, like his daytime activities, is abnormal.
B) James is experiencing physiological changes that are normal for the third stage of sleep.
C) James is experiencing unusual sleep because during the day he engaged in strenuous physical activities.
D) James is experiencing physiological changes that are normal during REM sleep.

Question

Quizplus · Accepted Answer

The rapid, irregular brain waves, increased heart rate and blood pressure, and limp muscles all indicate REM (rapid eye movement) sleep, which is characterized by physiological changes such as these. Since James has only been sleeping for 90 minutes, it is likely that he has just entered REM sleep for the first time in his sleep cycle. Therefore, option D is the most likely conclusion. Option A is incorrect because there is no evidence to suggest that James is chronically sleep-deprived or that his sleep during the day is abnormal. Option B is incorrect because the symptoms described are not consistent with the third stage of sleep. Option C is incorrect because physical activity during the day is not relevant to REM sleep.

James Has Been Sleeping for About 90 Minutes When His