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Biomedical subjects

M R Rosekind

Publications and source records attributed to M R Rosekind.

At least 19 recordsLinked to original sources
PubMed1998

Flight controller alertness and performance during spaceflight shiftwork operations.

Decreased alertness and performance associated with fatigue, sleep loss, and circadian disruption are issues faced by a diverse range of shiftwork operations personnel. During Space Transportation System (STS) operations, Mission Operations Directorate (MOD) personnel provide 24-hr. coverage of critical tasks. A joint NASA Johnson Space Center and NASA Ames Research Center project was undertaken to examine these issues in flight controllers during MOD shiftwork operations. An initial operational test of procedures and measures was conducted during the STS-53 mission in December 1992. The study measures included a Background Questionnaire, a subjective daily logbook completed on a 24-hour basis (to report sleep patterns, work periods, etc.), and an 8 minute performance and mood test battery administered at the beginning, middle, and end of each shift period. Seventeen flight controllers representing the 3 Orbit shifts participated. The initial results clearly support the need for further data collection during other STS missions to document baseline levels of alertness and performance during MOD shiftwork operations. Countermeasure strategies specific to the MOD environment are being developed to minimize the adverse effects of fatigue, sleep loss, and circadian disruption engendered by shiftwork operations. These issues are especially pertinent for the night shift operations and the acute phase advance required for the transition of day shift personnel into the night for shuttle launch. Implementation and evaluation of the countermeasure strategies to maximize alertness and performance is planned. As STS missions extend to further EDO (extended duration orbiters), and timelines and planning for 24-hour Space Station operations continue, alertness and performance issues related to sleep and circadian disruption will remain highly relevant in the MOD environment.

Adult↗
PubMed1998

Flight crew fatigue I: objectives and methods.

In 1980, NASA-Ames Research Center, Moffett Field, CA, initiated a program to assess flight crew fatigue, determine its potential operational consequences, and provide practical countermeasure suggestions. To assess the extent of the problem, crewmembers were monitored before, during, and after commercial short-haul (fixed-wing and helicopter aircraft), overnight cargo, and long-haul operations. A total of 197 volunteers were studied on 94 trip patterns with 1299 flight segments and 2046 h of flying time. The present paper outlines the program and describes the common methodology used in these studies, which are then presented in detail in the four subsequent papers. The sixth paper offers a synthesis of this work, reviewing the major causes of flight crew fatigue and making specific suggestions about ways to manage it in different operations.

Aviation↗
PubMed1998

Flight crew fatigue II: short-haul fixed-wing air transport operations.

We monitored 74 crewmembers before, during, and after 3-4-d commercial short-haul trips crossing no more than one time zone per 24 h. The average duty day lasted 10.6 duty hours, with 4.5 flight hours and 5.5 flights. On trips, crewmembers slept less, woke earlier, and reported having more difficulty falling asleep, with lighter, less restful sleep than pretrip. The consumption of caffeine, alcohol, and snacks increased on trip days, as did reports of headaches, congested nose, and back pain. The study suggests the following ways of reducing fatigue during these operations: base the duration of rest periods on duty hours as well as flight hours; avoid scheduling rest periods progressively earlier across a trip; minimize early duty report times; and inform crewmembers about strategic use of caffeine and alternatives to alcohol for relaxing before sleep.

Adult↗
PubMed1998

Flight crew fatigue III: North Sea helicopter air transport operations.

We studied 32 helicopter pilots before, during, and after 4-5 d trips from Aberdeen, Scotland, to service North Sea oil rigs. On duty days, subjects awoke 1.5 h earlier than pretrip or posttrip, after having slept nearly an hour less. Subjective fatigue was greater posttrip than pretrip. By the end of trip days, fatigue was greater and mood more negative than by the end of pretrip days. During trips, daily caffeine consumption increased 42%, reports of headache doubled, reports of back pain increased 12-fold, and reports of burning eyes quadrupled. In the cockpits studied, thermal discomfort and high vibration levels were common. Subjective workload during preflight, taxi, climb, and cruise was related to the crewmembers' ratings of the quality of the aircraft systems. During descent and approach, workload was affected by weather at the landing site. During landing, it was influenced by the quality of the landing site and air traffic control. Beginning duty later, and greater attention to aircraft comfort and maintenance, should reduce fatigue in these operations.

Adult↗
PubMed1998

Flight crew fatigue IV: overnight cargo operations.

We monitored 34 B-727 crewmembers before, during, and after 8-d commercial overnight cargo trips crossing no more than one time zone per 24 h. Daytime sleep episodes were 41% shorter and were rated as poorer than nighttime sleep episodes. When the layover was long enough, crewmembers usually slept again in the evening before going back on night duty. Nevertheless, the total sleep per 24 h on duty days averaged 1.2 h less than pretrip. The circadian temperature rhythm did not adapt completely to night duty, delaying by about 3 h. Self-rated fatigue was highest around the time of the temperature minimum, which occurred near the end of the nighttime duty period. On trip days, crewmembers ate more snacks and there was a marked increase in reports of headaches, congested noses, and burning eyes. Comparisons with daytime short-haul operations confirm that a daytime rest period does not represent the same sleep opportunity as a nighttime rest period of the same duration. We examine regulatory and scheduling options, and personal countermeasure strategies, that could help to reduce sleep loss during overnight cargo operations.

Adult↗
PubMed1998

Flight crew fatigue V: long-haul air transport operations.

We monitored 32 flight crewmembers before, during, and after 4-9 d commercial long-haul trips crossing up to 8 time zones per 24 h. The average duty day lasted 9.8 h, and the average layover 24.8 h. Layover sleep episodes averaged 105 min shorter than pretrip sleep episodes. However, in two-thirds of layovers, crewmembers slept twice so that their total sleep per 24 h on trips averaged 49 min less than pretrip. Greater sleep loss was associated with nighttime flights than with daytime flights. The organization of layover sleep depended on prior flight direction, local time, and the circadian cycle. The circadian temperature rhythm did not synchronize to the erratic environmental time cues. Consequently, the circadian low point in alertness and performance sometimes occurred in flight. On trip days, by comparison with pretrip, crewmembers reported higher fatigue and lower activation; drank more caffeine; ate more snacks and fewer meals; and there were marked increases in reports of headaches, congested nose, and back pain. Scheduling strategies and countermeasures to improve layover sleep, cockpit alertness, and performance, are discussed.

Aviation↗
PubMed1998

Flight crew fatigue VI: a synthesis.

Sleep, circadian rhythms, subjective fatigue, mood, nutrition, and physical symptoms were monitored in flight crews before, during, and after scheduled commercial operations. Duty-related changes in these measures were examined in four different types of air transport: short-haul fixed-wing; short-haul helicopter; domestic overnight cargo; and long-haul. The extent of these changes, and the duty-related and physiological factors contributing to them, are compared among the different operations. During all operations, the level of sleep loss was such that the majority of crewmembers would be expected to have become increasingly sleepy across trip days, with some experiencing performance decrements. In addition, during overnight cargo and long-haul operations, crewmembers were sometimes flying aircraft during the circadian low point in alertness and performance. Specific recommendations for reducing flight crew fatigue are offered for each operating environment.

Adult↗
PubMed1997

Rotating shiftwork schedules: can we enhance physician adaptation to night shifts?

OBJECTIVES: To evaluate the effectiveness of a broad, literature-based night shiftwork intervention for enhancement of emergency physicians' (EPs') adaptation to night rotations. METHODS: A prospective, double-blind, active placebo-controlled study was conducted on 6 attending physicians in a university hospital ED. Three data sets were collected under the following conditions: baseline, after active placebo intervention, and after experimental intervention. In each condition, data were collected when the physicians worked both night and day shifts. Measurements included ambulatory polysomnographic recordings of the main sleep periods, objective performance tests administered several times during the subjects' shifts, and daily subjective ratings of the subjects' sleep, moods, and intervention use. RESULTS: The subjects slept an average of 5 hr 42 min across all conditions. After night shifts, the subjects slept significantly less than they did after day shifts (5 hr 13 min vs 6 hr 20 min; p < 0.05). The physicians' vigilance reaction times and times for intubation of a mannequin were significantly slower during night shifts than they were during day shifts (p = 0.007 and p < 0.04, respectively), but performances on ECG analysis did not significantly differ between night and day shifts. Mood ratings were significantly more negative during night shifts than they were during day shifts (more sluggish p < 0.04, less motivated p < 0.03, and less clear thinking p < 0.04). The strategies in the experimental intervention were used 85% of the time according to logbook entries. The experimental and active placebo interventions did not significantly improve the physician's performance, or mood on the night shift, although the subjects slept more after both interventions. CONCLUSIONS: Although the experimental intervention was successfully implemented, it failed to significantly improve attending physicians' sleep, performance, or mood on night shifts. A decrease in speed of intubation, vigilance reaction times, and subjective alertness was evident each time the physicians rotated through the night shift. These findings plus the limited sleep across all conditions and shifts suggest that circadian-mediated disruptions of waking neurobehavioral functions and sleep deprivation are problems in EPs.

Adaptation, Physiological↗
PubMed1996

Managing fatigue in operational settings. 1: Physiological considerations and countermeasures.

The authors consider three aspects of managing fatigue in the workplace. They provide a brief overview of important scientific findings related to sleep and circadian physiology that establish the psychobiological foundation of fatigue. Their major focus is on the relevance of these findings to operational settings. In addition, they provide examples to describe practical fatigue countermeasures that can be used in operational settings.

Circadian Rhythm↗
PubMed1996

Managing fatigue in operational settings 2: An integrated approach.

The six domains that must be addressed in managing fatigue in operational settings are identified, and examples of how the aviation industry is dealing with the problems in each domain are given. Challenges facing healthcare providers in managing fatigue are also discussed.

Aviation↗
PubMed1994

Relationship of day versus night sleep to physician performance and mood.

STUDY OBJECTIVE: To document and analyze the quality and quantity of emergency physicians' sleep as a function of day and night shift work, and to compare cognitive and motor performance and mood during day and night shifts. DESIGN: Six physicians were monitored for two 24-hour periods. One period consisted of daytime work and nocturnal sleep and the second consisted of daytime sleep and nighttime work. SETTING: The emergency department of Stanford University Medical Center and physicians' homes. PARTICIPANTS: Six attending emergency physicians. INTERVENTIONS: Ambulatory polysomnographic recorders continuously gathered EEG, electro-oculogram, and electromyograph data throughout each observation period. Physicians filled out hourly mood ratings and completed a set of two performance tests five times throughout the day. RESULTS: Physicians had significantly less sleep (496.6 minutes versus 328.5 minutes, P = .02) when sleeping during the day as compared with sleeping at night. Significant performance decrements were also found. Physicians working nights were slower at intubating a mannequin (31.56 seconds versus 42.2 seconds, P = .04) and were more likely to commit errors as their shift progressed (P = .04). Physicians in both conditions were more likely to make errors during a simulated triage test toward the end of their shifts (P = .02). Subjects also rated themselves significantly less sleepy (P < .01), happier (P < .01), and more clear thinking (P < .01) when working day versus night shifts. CONCLUSION: Attending emergency physicians get less sleep and are less effective when performing manual and cognitive tests while working night shifts with day sleep compared with working day shifts with night sleep.

Adult↗
PubMed1994

Fatigue in operational settings: examples from the aviation environment.

The need for 24-h operations creates nonstandard and altered work schedules that can lead to cumulative sleep loss and circadian disruption. These factors can lead to fatigue and sleepiness and affect performance and productivity on the job. The approach, research, and results of the NASA Ames Fatigue Countermeasures Program are described to illustrate one attempt to address these issues in the aviation environment. The scientific and operational relevance of these factors is discussed, and provocative issues for future research are presented.

Aerospace Medicine↗
PubMed1993

Age, circadian rhythms, and sleep loss in flight crews.

Age-related changes in trip-induced sleep loss, personality (n = 205), and the pre-duty temperature rhythm (n = 91) were analyzed in crews from various flight operations. Eveningness decreased with age (subjects aged 20-30 were more evening-type than subjects over 40). The minimum of the baseline temperature rhythm occurred earlier with age (earlier in subjects aged 30-50 than in subjects aged 20-30). The amplitude of the baseline temperature rhythm declined with age (greater in subjects aged 20-30 than in subjects over 40). Average daily percentage sleep loss during trips increased with age. Among crewmembers flying longhaul flight operations, subjects aged 50-60 averaged 3.5 times more sleep loss per day than subjects aged 20-30. These studies support previous findings that evening types and subjects with later peaking temperature rhythms adapt better to shift work and time zone changes. Age and circadian type may be important considerations for duty schedules and fatigue countermeasures.

Adaptation, Physiological↗
PubMed1992

The epidemiology and occurrence of insomnia.

Although the definitions of insomnia have changed over the last decade to include the perceptions of patients and the effects of disturbed sleep on daytime function, no clear measure exists for isolating the scope of the problem within the general population. A 1979 Gallup poll survey showed that 95% of the adult population had experienced insomnia. The current literature maintains consistently that approximately one third of all people have sleep problems in any given year. Of those, only half consider the problem serious enough to seek medical advice. Sleep disorders appear to effect women more often than men, and the complaints increase with age. Younger people tend to have trouble falling asleep, while older people have difficulty maintaining sleep. The many varieties of sleep disorders and the diverse etiologies underlying them make it crucial that the individual sleep problem be understood clearly. An accurate diagnosis should drive treatment.

Adult↗
PubMed1990

Sleep, clonidine, and their interactive effect on growth hormone secretion in normal men.

Central alpha 2-adrenergic function is often inferred from the growth hormone (GH) response to clonidine, despite the drug's known hypnotic effect and the accepted cholinergic mechanism for sleep-related GH secretion. We examined the effect of daytime sleep on GH secretion in normal men taking placebo or clonidine orally, using a two-group blind design (placebo, clonidine; n = 9 each). Each subject participated in two morning sessions monitored by polysomnography: wake (sleep actively prevented) and sleep (subjects asked to sleep for 3 hr after receiving placebo or clonidine). Blood samples were drawn at times -15 min, 0, and every 30 min for 3 hr after the test dose was given. The total sleep time was similar for both groups. The placebo/wake group had lower GH responses than the other three groups. None of the GH responses in the clonidine/sleep group were significantly different from those in the placebo/sleep group; and the peak GH micrograms/L, mean +/- SD) was 16.9 +/- 10.9 vs. 14.6 +/- 10.5, respectively. We conclude that the GH response to clonidine may not be indicative of alpha 2-adrenergic function if sleep is permitted during the test.

Administration, Oral↗
PubMed1989

Sleepiness and nap sleep following a morning dose of clonidine.

The effects of a single oral dose of clonidine on morning nap sleep and daytime sleepiness were evaluated in 18 normal young adult male volunteers aged 18-21 years. Polysomnography and subjective sleepiness (Stanford Sleepiness Scale and linear analog sleepiness rating scale) measures were obtained on 2 mornings. Half the subjects received placebo and half clonidine (0.25-0.3 mg) on both occasions. Subjects were instructed to stay awake on the first morning (wake) and to sleep on the second (sleep). Efforts were made to help subjects maintain arousal on the wake day. Results from the wake morning showed that clonidine subjects were significantly sleepier than placebo subjects as measured by introspection. In addition, clonidine subjects tended to have more polysomnographic signs of sleepiness (microsleeps) when not actively aroused. On the sleep morning, clonidine and placebo subjects slept for approximately 90% of the 3-h nap. Stage 1 and rapid-eye-movement (REM) sleep were significantly reduced and stage 2 sleep significantly increased in the clonidine group. In conclusion, a morning dose of clonidine produced profound sedation in waking subjects and marked REM suppression in sleeping subjects.

Adolescent↗