What is the total sleep time (TST), in minutes given the data?

What is the total sleep time (TST), in minutes given the data?

• A. 275
• B. 360
• C. 300
• D. 230

Answer: (A)

Total sleep time is how many minutes were actually spent asleep during the night. To get it, subtract the time spent awake in bed from the total time in bed (or subtract WASO from the sleep period length). In the data, the sleep period spans 7 hours in bed (420 minutes). The total time awake after sleep onset (WASO) is 145 minutes. 420 minus 145 equals 275 minutes spent asleep. That matches the given correct value. If WASO were different, TST would shift accordingly. Note that sleep onset latency is not part of TST, since it reflects time before sleep begins.

Total sleep time is how many minutes were actually spent asleep during the night. To get it, subtract the time spent awake in bed from the total time in bed (or subtract WASO from the sleep period length).

In the data, the sleep period spans 7 hours in bed (420 minutes). The total time awake after sleep onset (WASO) is 145 minutes. 420 minus 145 equals 275 minutes spent asleep. That matches the given correct value.

If WASO were different, TST would shift accordingly. Note that sleep onset latency is not part of TST, since it reflects time before sleep begins.