Final answer:
The statement that most people spend about 75 percent of their sleep time in REM sleep is false. REM sleep only constitutes approximately 20-25% of an adult's sleep cycle, with the remainder being non-REM sleep.
Step-by-step explanation:
Most people spend about 75 percent of their sleep time in Rapid Eye Movement (REM) sleep - this statement is false. REM sleep is just one phase of the sleep cycle, and not the longest one. Sleep is divided into REM sleep and non-REM (NREM) sleep, and REM is characterized by rapid movements of the eyes, brain waves similar to those during wakefulness, and muscle paralysis (except for muscles that control respiration and circulation). A typical sleep cycle starts with NREM sleep stages before transitioning to REM. Throughout the night, an individual will cycle through these stages multiple times, with REM periods getting longer towards the morning. However, REM sleep only constitutes about 20-25% of the sleep cycle in adults. Conditions like REM sleep behavior disorder (RBD) show REM's notable effect on physical movement and dreaming during sleep, alongside other disorders affecting sleep like restless leg syndrome and sleep apnea, which signify the importance of understanding sleep patterns.