Publications by authors named "Nita Shattuck"

Study Objectives: The purpose of the study was to compare the fatigue levels, work/rest patterns, health-related behaviors, and well-being of galley workers with other sailors on US Navy ships while underway.

Methods: Analysis was based on a retrospective comparison of data from 3 fit-for-duty groups of sailors: 67 galley workers, 192 non-watchstanders, and 466 watchstanders. Participants completed questionnaires (Epworth Sleepiness Scale [ESS], Insomnia Severity Index [ISI], Pittsburgh Sleep Quality Index [PSQI], and Profile of Mood States [POMS]) and activity logs, and wore actigraphs.

View Article and Find Full Text PDF

Study Objectives: The study explores how sleep, sleep-related practices, and behaviors, in addition to various demographic and occupational characteristics, are related to overall mood of US Navy sailors when they are underway.

Methods: Longitudinal assessment of US Navy sailors performing their underway duties ( = 873, 79.2% males, median age 25 years).

View Article and Find Full Text PDF

Objectives: Under laboratory settings, light exposure upon waking at night improves sleep inertia symptoms. We investigated whether a field-deployable light source would mitigate sleep inertia in a real-world setting.

Methods: Thirty-six participants (18 female; 26.

View Article and Find Full Text PDF

Sleep inertia is the brief period of impaired alertness and performance experienced immediately after waking. Little is known about the neural mechanisms underlying this phenomenon. A better understanding of the neural processes during sleep inertia may offer insight into the awakening process.

View Article and Find Full Text PDF

Study Objectives: The influence of biological sex on sleep inertia symptoms is currently unknown. We investigated the role of sex differences in the subjective experience and objective cognitive manifestation of sleep inertia following nighttime awakenings.

Methods: Thirty-two healthy adults (16 female, 25.

View Article and Find Full Text PDF

Introduction: The study aimed to assess (1) the effect of the treatment with cervical headgear on patients' sleep-related attributes and well-being and (2) whether these sleep-related parameters (ie, sleep quality and quantity) were associated with patients' compliance during the orthodontic treatment.

Methods: The study protocol was based on a prospective longitudinal quasi-experimental design. Participants (n = 26; 9 males; mean age, 12.

View Article and Find Full Text PDF

As part of a larger project to provide recommendations regarding limitations and best practices for shifting aviators from day to night operations, a study was conducted to assess the efficacy of high energy visible (HEV) light to shift the circadian rhythm in humans. The study attempted to replicate the patterns of military aviators who could be required to shift abruptly from day to night flight operations. Simulated flight performance and salivary melatonin levels of 10 U.

View Article and Find Full Text PDF

Objectives: To determine whether United States Navy (USN) officers and enlisted personnel have different sleep and work patterns while underway on USN surface ships.

Methods: Variables of interest were assessed by actigraphy, activity logs, and validated questionnaires.

Results: The 2 groups had similar daily sleep (officers: 6.

View Article and Find Full Text PDF

Sleep inertia is the brief period of performance impairment and reduced alertness experienced after waking, especially from slow-wave sleep. We assessed the efficacy of polychromatic short-wavelength-enriched light to improve vigilant attention, alertness and mood immediately after waking from slow-wave sleep at night. Twelve participants (six female, 23.

View Article and Find Full Text PDF

Risks associated with fatigue that accumulates during work shifts have historically been managed through working time arrangements that specify fixed maximum durations of work shifts and minimum durations of time off. By themselves, such arrangements are not sufficient to curb risks to performance, safety, and health caused by misalignment between work schedules and the biological regulation of waking alertness and sleep. Science-based approaches for determining shift duration and mitigating associated risks, while addressing operational needs, require: (1) a recognition of the factors contributing to fatigue and fatigue-related risks; (2) an understanding of evidence-based countermeasures that may reduce fatigue and/or fatigue-related risks; and (3) an informed approach to selecting workplace-specific strategies for managing work hours.

View Article and Find Full Text PDF

Risks associated with fatigue that accumulates during work shifts have historically been managed through working time arrangements that specify fixed maximum durations of work shifts and minimum durations of time off. By themselves, such arrangements are not sufficient to curb risks to performance, safety, and health caused by misalignment between work schedules and the biological regulation of waking alertness and sleep. Science-based approaches for determining shift duration and mitigating associated risks, while addressing operational needs, require: (1) a recognition of the factors contributing to fatigue and fatigue-related risks; (2) an understanding of evidence-based countermeasures that may reduce fatigue and/or fatigue-related risks; and (3) an informed approach to selecting workplace-specific strategies for managing work hours.

View Article and Find Full Text PDF

Many workers routinely transition between day and night shiftsincluding pilots, where night flights are commonly considered more stressful. The physiological toll from this transition is not fully understood, though fatigue is a factor in many aviation accidents. This research investigated the changes in physiological markers of stress and cognitive performance as F-22 pilots transitioned from day flying to night flying.

View Article and Find Full Text PDF

Background: Due to their long workdays and erratic watch schedules, sailors on United States Navy (USN) ships often eat meals close to their bedtime, which may contribute to sleep disruption.

Aim: To assess the duration of meal-to-sleep (M-S) intervals in relation to timing of sailor workdays and watch schedules.

Methods: Longitudinal field assessment of USN sailors performing their underway duties ( = 234).

View Article and Find Full Text PDF

It is often assumed the quality of life of dayworkers is better than that of shiftworkers. Our findings from United States Navy (USN) sailors (N = 804, 78.4% males) showed dayworkers slept better, were less sleepy, and reported greater vigor and reduced fatigue (Profile of Mood States) than shiftworkers.

View Article and Find Full Text PDF

Study Objectives: This field study (a) assessed sleep quality of sailors on the U.S. Navy (USN) ships while underway, (b) investigated whether the Pittsburgh Sleep Quality Index (PSQI) scores were affected by occupational factors and sleep attributes, and (c) assessed whether the PSQI could predict impaired psychomotor vigilance performance.

View Article and Find Full Text PDF

Given the challenges of collecting reliable Psychomotor Vigilance Task (PVT) data in the field, this study compared a 3-min PVT on a hand-held device and wrist-worn device vs. a standardized laptop. The experiment utilized a randomized, repeated-measures design.

View Article and Find Full Text PDF

Objective: The study had two objectives: (a) to assess the prevalence of sleep-related habitability concerns in the berthing compartments of U.S. Navy surface ships and (b) to assess whether habitability issues in berthing compartments affected the sleep and well-being of crew members.

View Article and Find Full Text PDF

Introduction: This study examined the effects of simulated and actual vessel motion at high seas on task load and surgical performance.

Methods: This project was performed in phases. Phase I was a feasibility study.

View Article and Find Full Text PDF

Introduction: Attempting to expedite delivery of care to wounded war fighters, this study aimed to quantify the ability of medical and surgical teams to perform lifesaving damage control and resuscitation procedures aboard nontraditional US Navy Vessels on high seas. Specifically, it looked at the ability of the teams to perform procedures in shipboard operating and emergency rooms by analyzing motion of personnel during the procedures.

Methods: One hundred and twelve damage control and resuscitation procedures were performed during a voyage of the US Naval Ship Brunswick in transit from Norfolk, Virginia, to San Diego, California.

View Article and Find Full Text PDF

: To assess sleep-related difficulties (e.g., trouble staying asleep, oversleeping, falling asleep while on duty, disturbing dreams, sleep paralysis) and behavioral patterns of active-duty service members (ADSMs) performing security duties.

View Article and Find Full Text PDF

Shift work leads to adverse health outcomes including increased risk of cardiovascular disease. Heart rate (HR) and heart rate variability (HRV) are measures of cardiac autonomic activity and markers of cardiovascular disease and mortality. To investigate the effects of shift work on cardiac autonomic activity, we assessed the influence of simulated night work on HR and HRV, and dissociated the direct effects of circadian misalignment from those of sleep displacement and altered physical activity patterns.

View Article and Find Full Text PDF

Background: Sailors in the U.S. Navy are habitual shiftworkers, often experiencing circadian misalignment due to their irregular work/rest schedules.

View Article and Find Full Text PDF

The 10-min psychomotor vigilance test (PVT) is a widely used tool to assess behavioral alertness. In operational environments, however, the 3-min version of the PVT is more practicable. Under controlled laboratory conditions, we compared performance on the 3-min PVT on a wrist-worn device with the 3-min PVT on a laptop computer.

View Article and Find Full Text PDF