Page:Risk of performance errors due to sleep loss, circadian desynchronization, fatigue, and work overload.pdf/24

 or infringe on sleep and disrupt circadian rhythms in space. The space flight environment is reported to be noisy, poorly lit, and, for some, uncomfortable. Shifting schedules and heavy workloads, particularly for the shuttle astronauts, can pose additional challenges. Adequately assessing the environment and making recommendations to improve on it, as well as understanding individual vulnerabilities to sleep loss, is an essential part of preparing for future missions to the moon and Mars.

Astronauts have proven to be resourceful in mitigating sleep loss, circadian desynchronization, fatigue, extended work shifts, and work overload. Lighting, medication, good sleep hygiene, and improved scheduling serve as effective countermeasures for space flight crews. Much remains unknown concerning the best ways in which to implement these countermeasures, however, particularly over time. Some medications, for instance, are suspected to work differently in space than they do on Earth. Non-sleep medications may be required in flight, and the potential interactions between these and the sleep medications that are prescribed in space flight have yet to be determined. Similarly, additional research will aid in the use of artificial lighting as a countermeasure for increasing acute alertness as well as facilitating the alignment of circadian rhythms. The long-term safety and efficacy of light as a non-pharmaceutical aid for alertness, circadian shifting, and sleep will inform requirements for the lunar and Mars crew habitats as well as recommendations to the crews, flight controllers, and flight medical operations.

Continued research efforts are necessary to address the psychological and physiological health of individuals during and following space flight missions. The sleep and circadian systems affect immunology, hormone production, GI function, and cardiovascular health; sleep disruption can also serve as a contributing factor for the risk of behavioral conditions (Chapter 1) as well as for the risk that is related to poor team cohesion and psychosocial adaptation (Chapter 2). Similarly, countermeasures that are developed to aid the sleep and circadian system can also serve to enhance other aspects of health; as an example, research indicates that bright light can serve as an effective treatment for Seasonal Affective Disorder (Glickman et al., 1998). Addressing the sleep and circadian system thus further addresses other risks within BHP as well as enhances other discipline research areas that are related to the human system and health outcomes from living and working in the space flight environment.

Arnedt JT, Wilde GJ, Munt PW, MacLean AW. (2001) How do prolonged wakefulness and alcohol compare in the decrements they produce on a simulated driving task? ''Accid. Anal. Prev.'', 33(3):337–344.

Arnedt JT, Owens J, Crouch M, Stahl J, Carskadon MA. (2005) Neurobehavioral performance of residents after heavy night call vs. after alcohol ingestion. ''J. Am. Med. Assoc.'', 294(9):1025–1033.

Avinash D, Crudele C, Amin D, Robinson B, Dinges DF, Van Dongen HPA. (2005) Parameter estimation for a biomathematical model of PVT performance under laboratory conditions of chronic sleep restriction. Sleep Wake Research in the Netherlands, 16.

Ayas NT, Barger LK, Cade BE, Hashimoto DM, Rosner B, Cronin JW, Speizer FE, Czeisler CA. (2006) Extended work duration and the risk of self-reported percutaneous injuries in interns. ''J. Am. Med. Assoc.'', 296:1055–1062.

Balkin TJ, Bliese PD, Belenky G, Sing H, Thorne DR, Thomas M, Redmond DP, Russo M, Wesensten NJ. (2004) Comparative utility of instruments for monitoring sleepiness-related performance decrements in the operational environment. J. Sleep Res., 13(3), 219–227.