Massey Documents by Type

Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294

Browse

Subject: search.filters.subject.Psychomotor Vigilance Task

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Managing the challenge of fatigue for pilots operating ultra-long range flights.
    (Frontiers Media S.A., 2024-01-11) Signal TL; van den Berg MJ; Zaslona JL; Wu L; Hughes M; Johnston B; Dyer C; Drane M; Glover M; Fischer D
    Introduction: Ultra-long range (ULR) flights are defined as exceeding regulatory limits: normally 16 h flight time. They pose challenges due to long duty periods that could result in extended wakefulness and sleep loss, increasing the risk of fatigue. This study describes the mitigations used to manage fatigue in these operations. Two data collection phases were conducted on the Auckland-Chicago ULR route: when the route commenced (Study 1) and when the flight crew complement was altered (Study 2). Seasonal differences were also investigated. Methods: Study 1 involved 72 crew who completed diaries and wore an actigraph to record sleep pre-departure, throughout the trip, and on return. In-flight, fatigue, sleepiness and workload were reported, and reaction time performance was measured. Study 2 involved 75 crew and data collection in the northern summer and northern winter. Crew completed diaries throughout the trip. Results: Study 1 data found crew sleep longer than usual in the 24 h pre trip and post flights. On the shorter outbound flight in-flight sleep averaged 3.3 h and on the longer inbound flight, 3.3–3.8 h, with most crew taking 3 breaks. Ratings of sleepiness and fatigue increased, and reaction time performance declined across flights, with greater decrements on longer inbound flights. Pilots did not fully adjust their sleep patterns to local time during the layover and no seasonal differences were found. Comparisons between Study 1 and 2 showed no difference in ratings of fatigue and sleepiness or in-flight sleep duration with an altered crew complement. There was a trend for Captains to report greater workload and less in-flight sleep in Study 2. Discussion: Mitigations that allow for preparation and recovery are well utilized by crew. In-flight sleep is relatively short and ways of increasing the amount of sleep obtained should be considered. The incomplete adaptation of sleep during the layover has implications for rest break strategies on the return flight. The altered crew complement did not result in higher levels of fatigue or sleepiness or less in-flight sleep on average, although findings suggest a need to understand the effects of changing the crew complement on workload and in-flight sleep for Captains.
  • Thumbnail Image
    Item
    The effect of a two-week ketogenic diet, versus a carbohydrate-based diet, on cognitive performance, mood and subjective sleepiness during 36 hours of extended wakefulness in military personnel : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2022) Henderson, Lydia Rose
    Background: Sleep deprivation (SD) compromises cognitive performance of military personnel, jeopardising operational performance and safety. Since SD-related performance deficits coincide with decreased glucose metabolism in associated brain regions, the ketogenic diet (KD) may mitigate cognitive impairments by providing an alternative fuel source (i.e. ketone bodies [KB]). Aim: To investigate the effect of a 2-week KD compared with a carbohydrate (CHO)-based diet on cognitive function, mood and sleepiness during 36 hours of extended wakefulness. Methods: A randomised, cross-over trial was conducted with 7 military personnel (range, 26- 45 years). Participants ingested a KD (~25 g·day⁻¹ CHO) or CHO-based diet (~285 g·day⁻¹ CHO) for 14 days, immediately followed by 36 hours of wakefulness and separated by a 12-day washout period. Cognitive performance (5-minute Psychomotor Vigilance Task; PVT), mood (fatigue and vigour), subjective sleepiness, and capillary blood glucose and D-β-hydroxybutyrate (D-βHB) concentrations were measured every 2 hours (1, 3 and 5 hours after each meal). Linear mixed models tested the effect of diet, period (6 x 6-hourly bins), test time (1-3) within periods, and their interactions. Results: D-βHB was higher (+0.75 to +1.45 mM; p < 0.001) and glucose was lower (-0.26 to -1.16 mM; p < 0.01) in the KD compared with the CHO-based diet. The KD improved performance for all PVT variables (number of lapses, mean reciprocal reaction time [RRT], slowest 10% RT and fastest 10% RT) (p < 0.05), mood (p = 0.001), and sleepiness (p < 0.001) compared with the CHO-based diet; however, there were no interactions with period or test. Number of lapses and subjective sleepiness increased, and mood, mean RRT and slowest 10% RT deteriorated during the 36 hours of extended wakefulness independent of diet (all p < 0.01). Circadian effects were also observed for fastest 10% RT, mood and sleepiness independent of diet (all p < 0.01). Conclusion: The KD appeared to improve cognitive performance, mood and sleepiness during 36 hours of extended wakefulness compared with the CHO-based diet. This suggests the KD could be considered for military operations when sleep deprivation is anticipated.