Sleep efficiency
From Wikipedia, the free encyclopedia
Sleep efficiency (SE) is the ratio between the time a person spends asleep, and the total time dedicated to sleep (i.e. both sleeping and attempting to fall asleep or fall back asleep). It is given as a percentage.[1] SE of 80% or more is considered normal/healthy with most young healthy adults displaying SE above 90%.[2][better source needed] SE can be determined with a polysomnograph and is an important parameter of a sleep study.[3]
Sleep efficiency is often described as the ratio between time spent asleep ("total sleep time (TST)"), and time spent "in bed" ("time in bed (TIB)"), however, TIB does not encompass "non-sleep-related activities" performed in bed (e.g. reading, watching television, etc.) as the phrase may seem to suggest.[1]