Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights

Dijk, Derk‐Jan; Neri, David F.; Wyatt, James K.; Ronda, Joseph M.; Riel, E; Cecco, Angela Ritz-De; Hughes, Rod J.; Elliott, A. R.; Prisk, G. Kim; West, John B.; Czeisler, Charles A.

doi:10.1152/ajpregu.2001.281.5.r1647

Cited by 207 publications

(184 citation statements)

References 26 publications

(34 reference statements)

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“…Crew sleep durations averaged <6.78 h (SE = 0.19 h) per day during the first 40 d of the mission, which was lower than during all subsequent 40-d mission periods (P < 0.05). This value is close to actigraphically recorded sleep times of astronauts on US Space Shuttle missions (6) and International Space Station expeditions, where work tempos have historically been high. Sleep durations chronically at <7 h per day result in cumulative neurobehavioral performance deficits across days (7,8), making chronic partial sleep loss a risk to optimal performance in space (3).…”

Section: Resultssupporting

confidence: 72%

Mars 520-d mission simulation reveals protracted crew hypokinesis and alterations of sleep duration and timing

Basner

Dinges

Mollicone

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

152

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The success of interplanetary human spaceflight will depend on many factors, including the behavioral activity levels, sleep, and circadian timing of crews exposed to prolonged microgravity and confinement. To address the effects of the latter, we used a highfidelity ground simulation of a Mars mission to objectively track sleep-wake dynamics in a multinational crew of six during 520 d of confined isolation. Measurements included continuous recordings of wrist actigraphy and light exposure (4.396 million min) and weekly computer-based neurobehavioral assessments (n = 888) to identify changes in the crew's activity levels, sleep quantity and quality, sleep-wake periodicity, vigilance performance, and workload throughout the record-long 17 mo of mission confinement. Actigraphy revealed that crew sedentariness increased across the mission as evident in decreased waking movement (i.e., hypokinesis) and increased sleep and rest times. Light exposure decreased during the mission. The majority of crewmembers also experienced one or more disturbances of sleep quality, vigilance deficits, or altered sleep-wake periodicity and timing, suggesting inadequate circadian entrainment. The results point to the need to identify markers of differential vulnerability to hypokinesis and sleepwake changes during the prolonged isolation of exploration spaceflight and the need to ensure maintenance of circadian entrainment, sleep quantity and quality, and optimal activity levels during exploration missions. Therefore, successful adaptation to such missions will require crew to transit in spacecraft and live in surface habitats that instantiate aspects of Earth's geophysical signals (appropriately timed light exposure, food intake, exercise) required for temporal organization and maintenance of human behavior.sleep-wake regulation | astronaut T he success of human interplanetary spaceflight, which is anticipated to be in this century, will depend on the ability of spacefarers to remain confined and isolated from Earth much longer than previous missions or simulations, while maintaining the intensity and timing of behavioral activity necessary to accomplish the mission and mitigate the effects of microgravity. A total of four people have spent >1 y in space, with the record of 437 consecutive days on the Mir space station set by Valery Polyakov. The longest Earth-based spaceflight simulation involved four Russians confined in connected hyperbaric chambers for 240 consecutive days. Antarctic winter-over missions have extended up to 363 d. Prediction of how prolonged confinement affects activity levels and sleep-wake dynamics of space explorers is needed to inform spacecraft habitability requirements, crew selection, and behavioral countermeasures during interplanetary missions (1-3). To address this need, we obtained objective neurobehavioral data on the activity patterns of a multinational, culturally diverse crew of six males with backgrounds in engineering, medicine, physiology, and space training, who participated in a high-fidelity g...

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Section: Resultssupporting

confidence: 72%

Mars 520-d mission simulation reveals protracted crew hypokinesis and alterations of sleep duration and timing

Basner

Dinges

Mollicone

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

152

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“…The resulting inappropriate functioning, consistent with the hypothesized circadian regulation of brain metabolism (44), may be an important factor contributing to the increased risk of accident associated with circadian misalignment (45). Evidence of significant sleep loss and disruption of circadian rhythms in astronauts (42) and associated performance decrements are also reported during space missions. In these situations, sleep and circadian disruptions could have serious consequences on the effectiveness, health, and safety of astronaut crews (46,47).…”

Section: Discussionmentioning

confidence: 92%

“…Jet-lag, shift work, and other circadian rhythm sleep disorders such as advanced and delayed sleep phase types and free-running type are all associated, to different extents, with a condition in which the circadian system is out of synchrony with the light:dark/rest-activity cycle. The generally associated symptoms range from cognitive and psychomotor impairment to sleep disruptions (18,(39)(40)(41)(42) and endocrine disturbances (43). The resulting inappropriate functioning, consistent with the hypothesized circadian regulation of brain metabolism (44), may be an important factor contributing to the increased risk of accident associated with circadian misalignment (45).…”

Section: Discussionmentioning

confidence: 99%

Entrainment of the human circadian pacemaker to longer-than-24-h days

Gronfier

Wright

Kronauer

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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181

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Entrainment of the circadian pacemaker to the light:dark cycle is necessary for rhythmic physiological functions to be appropriately timed over the 24-h day. Nonentrainment results in sleep, endocrine, and neurobehavioral impairments. Exposures to intermittent bright light pulses have been reported to phase shift the circadian pacemaker with great efficacy. Therefore, we tested the hypothesis that a modulated light exposure (MLE) with bright light pulses in the evening would entrain subjects to a light:dark cycle 1 h longer than their own circadian period ( ). Twelve subjects underwent a 65-day inpatient study. Individual subject's circadian period was determined in a forced desynchrony protocol. Subsequently, subjects were released into 30 longer-than-24-h days (daylength of ؉ 1 h) in one of three light:dark conditions: (i) Ϸ25 lux; (ii) Ϸ100 lux; and (iii) MLE: Ϸ25 lux followed by Ϸ100 lux, plus two 45-min bright light pulses of Ϸ9,500 lux near the end of scheduled wakefulness. We found that lighting levels of Ϸ25 lux were insufficient to entrain all subjects tested. Exposure to Ϸ100 lux was sufficient to entrain subjects, although at a significantly wider phase angle compared with baseline. Exposure to MLE was able to entrain the subjects to the imposed sleep-wake cycles but at a phase angle comparable to baseline. These results suggest that MLE can be used to entrain the circadian pacemaker to non-24-h days. The implications of these findings are important because they could be used to treat circadian misalignment associated with space flight and circadian rhythm sleep disorders such as shiftwork disorder.light ͉ melatonin ͉ phase angle of entrainment ͉ phase response curve ͉ sleep Entrainment of a circadian rhythm by a zeitgeber fulfills biological purpose in providing a very distinct phase relationship between the periodicity of the organism and that of the environment.J. Aschoff (1) T o be of functional significance for the organism, circadian rhythms must be entrained to the 24-h day. For nearly all species studied, the light:dark cycle is the most powerful circadian synchronizer. The resetting capacity of light depends on its intensity, timing, duration, temporal pattern, and spectral composition (2-7). In totally blind people, the circadian timekeeping system often loses synchrony with the earth's 24-h light:dark cycle (8). Well described in animals (9-11) and only recently confirmed in humans (12), entrainment of the circadian system depends on (i) its intrinsic period ( ), (ii) the light:dark cycle to which it is exposed (T; T-cycle), and (iii) the strength of the entraining stimulus (zeitgeber, from German for "time giver"). The generally accepted nonparametric model of circadian entrainment predicts immediate phase shifting in response to light, according to a phase response curve (PRC) (3, 9, 13). In humans, for whom the intrinsic period is on average Ϸ24.2 h (14), entrainment to the solar day of earth (T ϭ 24 h) requires that the biological clock be ''reset'' by on average of Ϸ0.2 h per day in th...

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“…Moreover, the systematic relationship between total daily time in bed and waking neurobehavioral outcomes observed in this study suggests that time in bed (as a surrogate for total physiological sleep time) is substantively predictive of daytime performance. This has useful implications for space operations, as time in bed can be estimated using inexpensive, noninvasive, space flight-ready technologies such as actigraphy [19].…”

Section: Discussionmentioning

confidence: 99%

Response surface mapping of neurobehavioral performance: Testing the feasibility of split sleep schedules for space operations

et al. 2008

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The demands of sustaining high levels of neurobehavioral performance during space operations necessitate precise scheduling of sleep opportunities in order to best preserve optimal performance. We report here the results of the first split-sleep, dose-response experiment involving a range of sleep/wake scenarios with chronically reduced nocturnal sleep, augmented with a diurnal nap. To characterize performance over all combinations of split sleep in the range studied, we used response surface mapping methodology. Waking neurobehavioral performance was studied in N=90 subjects each assigned to one of 18 sleep regimens consisting of a restricted nocturnal anchor sleep period and a diurnal nap. Psychomotor vigilance task performance and subjective assessments of sleepiness were found to be primarily a function of total time in bed per 24 h regardless of how sleep was divided among nocturnal anchor sleep and diurnal nap periods. Digit symbol substitution task performance was also found to be primarily a function of total time in bed per 24 h; however, accounting for nocturnal sleep duration and nap duration separately provided a small but significant enhancement in the variance explained. The results suggest that reductions in total daily sleep result in a near-linear accumulation of impairment regardless of whether sleep is scheduled as a consolidated nocturnal sleep period or split into a nocturnal anchor sleep period and a diurnal nap. Thus, split sleep schedules are feasible and can be used to enhance the flexibility of sleep/work schedules for space operations involving restricted nocturnal sleep due to mission-critical task scheduling. These results are generally applicable to any continuous industrial operation that involves sleep restriction, night operations, and shift work.

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Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights

Cited by 207 publications

References 26 publications

Mars 520-d mission simulation reveals protracted crew hypokinesis and alterations of sleep duration and timing

Mars 520-d mission simulation reveals protracted crew hypokinesis and alterations of sleep duration and timing

Entrainment of the human circadian pacemaker to longer-than-24-h days

Response surface mapping of neurobehavioral performance: Testing the feasibility of split sleep schedules for space operations

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