This document contains a reading comprehension passage and questions about sleep. It discusses that sleep alternates between non-dreaming and REM dreaming sleep in cycles throughout the night. Non-dreaming sleep makes up three-quarters of the night and repairs the body, while REM sleep refreshes the brain. A study found that long sleepers who slept over 8.5 hours were poor sleepers and did not feel refreshed, while 6 hours of good sleep is more restorative than 8 hours of troubled sleep.
This document contains a reading comprehension passage and questions about sleep. It discusses that sleep alternates between non-dreaming and REM dreaming sleep in cycles throughout the night. Non-dreaming sleep makes up three-quarters of the night and repairs the body, while REM sleep refreshes the brain. A study found that long sleepers who slept over 8.5 hours were poor sleepers and did not feel refreshed, while 6 hours of good sleep is more restorative than 8 hours of troubled sleep.