Dubious bargain: trading sleep for Leno and Letterman

Abstract

Study objectives: Sleeping less than 7 hours daily impairs alertness and is associated with increased obesity, morbidity, and mortality; yet up to 40% of US adults do so. Population data indicate work time is the primary activity reciprocally related to sleep time in the United States. Reducing work time and its economic benefits to increase sleep time may not be feasible for most of the population. We sought to identify waking activities under discretionary control and adjacent to the sleep period that would be a more feasible source for increasing sleep time.

Design/participants: American Time Use Survey data from 21,475 respondents aged > or = 15 years were pooled for the years 2003-2006 to explore activities in 2-hour periods prior to going to bed and past getting up on weekdays.

Interventions: N/A.

Results: Long workers (> or = 8 hours) terminated bed time an average of 0.68 h earlier than short workers (< 8 hours, P < 0.0001) and 1.31 h earlier than respondents not working on the interview day (P < 0.001), but time of going to bed did not differ among groups (22:37 vs. 22:42 vs. 22:37, respectively, P = 0.385). Watching television was the primary activity people engaged in before going to bed, accounting for 55.6 min (46.3%) of the 2-h pre-bed period. In the morning, travel time and work time increased steadily toward the end of the post-awakening 2-h period, accounting for 14.8% and 12.3%, respectively.

Conclusions: Watching television may be an important social Zeitgeber for the time of going to bed. Watching less television in the evening and postponing work start time in the morning appear to be the candidate behavioral changes for achieving additional sleep. While the timing of work may not be flexible, giving up some TV viewing in the evening should be possible to reduce chronic sleep debt and promote adequate sleep in those who need it.

Figures

Figure 1

Panels A and B show distributions of time of going to bed (A) and time of getting up (B) for respondents who did not work (black lines, N = 9770), who worked less than 8 h (gray lines, N = 5589), and for those who worked 8 h or more (broken black lines, N = 6,116).

Figure 2

Panels A and B show the time course of the 6 most common waking activities in 2-h periods prior to going to bed (−2h to time of going to bed in panel A) and after getting up (time of getting up to +2h in panel B).