# Measuring Sleep Efficiency: What Should the Denominator Be? https://jcsm.aasm.org/doi/10.5664/jcsm.5498 [[Sleep]] #sleep [[HOPES Project Index]] Before reading this: My curiosity is 1. When we say that patient's sleep pattern can be early relapse signs of mental illness, are we referring to sleep efficiency? Sleep hours? 2. What is Fitbit tracking? ---- - What is the definition of Sleep Efficiency (SE) - Ratio of total Sleep time (TST) to Time in bed (TIB) x 100. - Not a good construction because we do many other things in bed beside sleeping. - So alternate denominator is considered : - Duration of the sleep episode (DSE) - DSE = Sleep onset latency (SOL) + TST + Time awake after initial sleep onset but before the final awakening (WASO) + time attempting to sleep after final awakening (TASAFA). - SE = TST / DSE (× 100). --- Related to [[The prevalence and management of Poor sleep quality in a secondary care mental health population]]