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To the Editor: It has become increasingly clear that insufficient sleep and disrupted circadian rhythms are a major public health problem. For instance, in 1988 the cost of sleep-related accidents exceeded $56 billion and included 24,318 deaths and 2,474,430 disabling injuries.1 Major disasters, including the nuclear accident at Chernobyl, the Exxon Valdez oil spill, and the destruction of the space shuttle Challenger, have been linked to insufficient sleep, disrupted circadian rhythms, or both on the part of involved supervisors and staff.2,3 It has been suggested that as a society we are chronically sleep-deprived4 and that small additional losses of . . .