How is WASO (Wake After Sleep Onset) calculated?

How is WASO (Wake After Sleep Onset) calculated?

• A. Total minutes of wake between sleep onset and last sleep epoch.
• B. Percentage of wake time relative to total sleep time.
• C. Sleep efficiency index is TST/TRT × 100.
• D. REM latency measured as First REM epoch minus First sleep epoch.

Answer: (A)

WASO represents the total time a person is awake after sleep begins during the sleep period. It is calculated by summing every wake interval that occurs after sleep onset up to the final awakening, and the result is given in minutes. This quantity shows how fragmented the sleep is and how much time is spent awake while trying to sleep. Why this fits best: WASO is defined specifically as the accumulated awake time after the person falls asleep, not a percentage, and not a different metric like sleep efficiency or REM latency. Expressing wake time as a percentage would describe a proportion rather than the actual minutes. Sleep efficiency uses total sleep time relative to time in bed, and REM latency measures the time from sleep onset to the first REM period, which are separate concepts.

WASO represents the total time a person is awake after sleep begins during the sleep period. It is calculated by summing every wake interval that occurs after sleep onset up to the final awakening, and the result is given in minutes. This quantity shows how fragmented the sleep is and how much time is spent awake while trying to sleep.

Why this fits best: WASO is defined specifically as the accumulated awake time after the person falls asleep, not a percentage, and not a different metric like sleep efficiency or REM latency. Expressing wake time as a percentage would describe a proportion rather than the actual minutes. Sleep efficiency uses total sleep time relative to time in bed, and REM latency measures the time from sleep onset to the first REM period, which are separate concepts.