ABSTRACT
The ability to awaken oneself from sleep at a preselected time without external means (such as alarm clocks) was studied using, first, subjective and, second, objective methods. First, in a telephone survey of 269 unselected adults, over one-half said that they never use an alarm clock (or other external means) or always awaken before it. Another 24% said that they sometimes awaken before the alarm. Furthermore, this ability positively correlated with age and was related to consistency in the amount of nightly sleep but not consistency in wake-up time. Second, 15 people who said they regularly self-awaken were objectively tested for this ability in their own beds using actigraphy for three consecutive nights while choosing their own wake-up times. Five awoke within 10 minutes of their target time (mostly before) on each night, five did so on two of the three nights, and of the remaining five, four did so on one night. Choice of target times varied considerably within subjects but more so for those who were more successful. Taken together these results show that many people have the ability to regularly awaken themselves from sleep at a desired time and that such an ability is of practicable utility.