Final answer:
It is impossible to sleepwalk during REM sleep due to muscle paralysis except for muscles controlling circulation and respiration.
Step-by-step explanation:
During REM sleep, it is impossible for someone to sleepwalk. REM stands for rapid eye movement, and this phase is characterized by brain waves very similar to those during wakefulness, along with darting movements of the eyes under closed eyelids. Importantly, REM sleep is associated with paralysis of muscle systems in the body, except those that control circulation and respiration, preventing movement of voluntary muscles. Therefore, no movement or behaviors such as sleepwalking occur during REM sleep in a normal individual. This stage of sleep contrasts with NREM (non-REM) sleep stages, particularly Stage 2, which is characterized by sleep spindles and K-complexes and where sleepwalking is more likely to happen.