Which value best represents the normal REM percentage during total sleep time?

Which value best represents the normal REM percentage during total sleep time?

• A. 20-25%
• B. 50%
• C. 5-10%
• D. 35%

Answer: (A)

REM sleep makes up roughly one-fifth to one-quarter of total sleep time. In a typical adult night, about 20-25% of the entire sleep period is REM, even though the REM portion tends to rise in the later cycles. This range best matches the average distribution seen across a full night of sleep. The other numbers are outside what’s normally observed: REM is not half the night, nor as low as 5-10%, nor as high as 35%. Age and individual variation can shift exact amounts, but 20-25% remains the standard reference for normal REM percentage of total sleep time.

REM sleep makes up roughly one-fifth to one-quarter of total sleep time. In a typical adult night, about 20-25% of the entire sleep period is REM, even though the REM portion tends to rise in the later cycles. This range best matches the average distribution seen across a full night of sleep. The other numbers are outside what’s normally observed: REM is not half the night, nor as low as 5-10%, nor as high as 35%. Age and individual variation can shift exact amounts, but 20-25% remains the standard reference for normal REM percentage of total sleep time.