How is a patient's sleep efficiency calculated?

Sleep efficiency is a measure used to assess the effectiveness of a patient's sleep. It is calculated by dividing total sleep time by the total time spent in bed. This metric provides insight into how much of the time in bed is actually spent sleeping, which is important for evaluating sleep quality.

A higher sleep efficiency percentage indicates that a person is able to maintain sleep for a large portion of the time they are in bed, while a lower percentage suggests frequent awakenings or difficulty staying asleep. Factors influencing sleep efficiency can include sleep disorders, environmental noises, and individual health conditions.

The other options do not accurately reflect how sleep efficiency is calculated. Measuring REM sleep duration solely provides information about the amount of rapid eye movement sleep, which is only one phase of the overall sleep cycle. Dividing total awake time by total in-bed time does not yield a meaningful measure of sleep quality. Averaging nightly sleep hours does not account for the time spent in bed or the actual amount of sleep obtained during those hours. Thus, the correct calculation focuses on the ratio of total sleep time to total time spent in bed, making it a reliable measure of sleep efficiency.