typically sleep only 6 to 6.5 hours. Polysomnography (sleep studies using electroencephalogram [EEG], electro-occulogram [EOG], and electromyogram [EMG] recordings) have shown more wakefulness and less slow-wave (deep) sleep in the final third of sleep episodes while in space and marked increases in rapid eye movement (REM or dreaming) sleep after return to earth (Dijk et al., 2001).
Astronauts frequently use hypnotics during flights (Putcha et al., 1999), and stimulants are available to ensure alertness during critical phases of the mission. Like Air Force pilots, as discussed earlier, astronauts are allowed to decide whether to take stimulants (usually dextroamphetamine). A final selection from Apollo 13 illustrates one astronaut’s decision-making process regarding the use of stimulants:
In the spacecraft, Lovell, Haise, and Swigert were in their accustomed places, all awake and all feeling reasonably alert. Lovell had decided against the Dexedrine tablets Slayton had prescribed for his crew last night, knowing that the lift from the stimulants would be only fleeting, and the subsequent letdown would leave them feeling even worse than they did now. For the time being, the commander had decided, the astronauts would get by on adrenaline alone. (Lovell and Kluger, 1994:318)
Fatigue countermeasures programs usually consist of an educational component (Comperatore and Kingsley, undated; Comperatore et al., 2001; Intermodal Transportation Institute, 2000a; NASA Ames Research Center, 1997; Smith-Coggins et al., 1997) and sometimes include schedule alterations (Intermodal Transportation Institute, 2000a; Sussman and Coplen, 2002). Employees are generally given information about circadian rhythms, sleep hygiene measures, shiftwork and its adverse affects, and a variety of strategies that can be used to counter fatigue (e.g., judicious use of caffeine, napping during night shifts) (NASA Ames Research Center, 2001; Rosekind et al., 1997). Some industries have also added information about sleep disorders to their presentations (Intermodal Transportation Institute, 2000a). Managers are urged to consider altering the starting times of shifts whenever possible to make schedules more compatible with circadian rhythms; to avoid scheduling employees to work more than two or three consecutive night shifts; and to provide adequate recovery times between shifts, especially when an employee is rotating off night shift. By 1997, 497 people from 230 organizations in 17 countries had participated in a 2-day trainers’ workshop run by the NASA Ames Fatigue Countermeasures Group (NASA Ames Research Center, 1997). Attendees have included representatives from all areas of aviation; other modes of transportation, including the rail, trucking, and maritime industries; health care; the petrochemical industry;