Because sedatives can increase dopamine, some patients do wake up from anesthesia feeling good and assuming that means they’re “well-rested” but no, it can’t replace sleep. Sedation vs. sleep puts the brain in different states.
During sleep, the brain moves between the slow waves of non-REM sleep and the fast waves of REM sleep. Under general anesthesia, brain rhythms are held hostage in the same state. The brain waves become so structured and regimented that they can’t transmit information, resulting in profound unconsciousness and amnesia. That’s why under full sedation, we don’t dream.