Novel software to help plan astronaut, shift worker schedules

A software that uses mathematical models to help astronauts and ground support personnel better adjust to shifting work and sleep schedules has been developed by researchers.

Shifting work schedules, if not planned out properly, can wreak havoc on a person's ability to get enough sleep, resulting in poor performance on the job.

Now, boffins funded by the National Space Biomedical Research Institute (NSBRI) believe that the new software could help people who do shift or night work or who experience jet lag due to travel across time zones.

"The best methods that we know to help people operate at peak performance are first to ensure that they get adequate sleep, and second that their work schedules are designed to be aligned with the natural body clock," said project leader Dr Elizabeth Klerman, associate team leader for NSBRI's Human Factors and Performance Team.

According to Klerman, a physician in the Division of Sleep Medicine at Brigham and Women's Hospital in Boston and associate professor at Harvard Medical School, the software has two components. The Circadian Performance Simulation Software (CPSS) uses complex mathematical formulas to predict how an individual will react to specific conditions. CPSS also allows users to interactively design a schedule, such as shifting sleep/wake to a different time, and predicts when they would be expected to perform well or poorly.

The second component, known as Shifter, then "prescribes" the optimal times in the schedule to use light to shift a person's circadian rhythm in order to improve performance at critical times during the schedule.

"If there is a mission event, such as a spacewalk, scheduled at one or two o'clock in the morning, what can we do to help the astronaut to be alert and functioning well at that time?" Klerman said. "Do we suggest a nap or caffeine? Do we shift their sleep/wake schedule? There are a variety of options that we would like to be able to provide."

Scientists know that an individual's performance and alertness are tightly regulated by several factors related to circadian rhythms and the sleep/wake cycle - length of time awake; the timing, intensity and wavelength of light; the amount of sleep the night before; and the body clock's perception of time. As a result, most people are not able to operate at peak job performance in the late night or early morning hours.

The situation for International Space Station astronauts is complicated by the fact that they often face schedules that are not uniform. A shift in scheduled sleep/wake time, due to an event such as docking, could be as much as eight or nine hours, with the transition taking place over a short period of time. "These dramatic shifts in schedule not only affect the body's ability to know what time it is, but also hinder the body's ability to give the appropriate signals to a person trying to wake up or go to sleep," Klerman said.