Figure 3-1. Sample integration within the BHP Element, and with other HRP Elements.
Evidence
Ground-based evidence
Studies, which include laboratory investigations (Category I) and field evaluations (Category II and Category III) of population groups that are analogous to astronauts (e.g., medical and aviation personnel), provide compelling evidence that working long shifts for extended periods of time contributes to sleep deprivation and can cause performance decrements, health problems, and other detrimental consequences, including accidents, that affect both the worker and others.
Performance Errors Relative to Sleep Loss and Extended Wakefulness
A meta-analysis (Category I) that was conducted by Pilcher and Huffcutt (1996) examined data that were drawn from 19 research studies to characterize the effects of sleep deprivation on specific types of human performance. Motor skills, cognitive skills, and mood were assessed in terms of: partial sleep deprivation (also known as sleep restriction), which is defined as fewer than 5 hours of sleep in a 24-hour period for 1 or more days; short-term total sleep deprivation (no sleep attained for fewer than 45 hours); and long-term sleep deprivation (no sleep attained for a period in excess of 45 hours). These researchers found that sleep-deprived subjects performed considerably worse on motor tasks, cognitive tasks, and measures of mood than did nonsleep-deprived subjects. The greatest impact on cognitive performance was seen from multiple days of partial sleep deprivation, although short- and long-term sleep deprivation also showed an effect. Meta-analyses of sleep deprivation effects in medical residents found deficits in both laboratory tasks and clinical tasks (Philibert, 2005).
The magnitude of the chronic partial sleep loss that has been experienced by astronauts in flight (Barger and Czeisler, 2008; Monk et al., 1998; Dijk et al., 2001; Kelly et al., 2005; Gundel et al., 1997; Santy et al., 1988; Frost et al., 1976) has been reported to negatively impact cognitive performance in multiple Category I, Category II, and Category III laboratory and field studies (Dinges et al., 1997; Lockley et al., 2004; Landrigan et
