TY - JOUR
T1 - The submariners’ sleep study
T2 - a field investigation of sleep and circadian hormones during a 67-day submarine mission with a strict 6-h-on/6-h-off watch routine
AU - Van Puyvelde, Martine
AU - Rietjens, Gerard
AU - Helmhout, Pieter
AU - Mairesse, Olivier
AU - Van Cutsem, Jeroen
AU - Pattyn, Nathalie
N1 - Publisher Copyright:
Copyright © 2022 the American Physiological Society.
PY - 2022/4
Y1 - 2022/4
N2 - The submarine working and living environment is an isolated, confined, and extreme (ICE) environment where a continuous on-watch is required to fulfill the tactical objectives. The current study examined whether a physiological and behavioral adjustment to an operational watch standing scheme occurred in terms of hormonal secretion (i.e., melatonin and cortisol) and sleep during a 67-day undersea mission. The crew followed a strict scheme of watch-on blocks at 0:00–06:00 h and at 12:00–18:00 h (group 1, diurnal sleep group) or watch-on blocks at 06:00–12:00 h and 18:00–24:00 h (group 2, nocturnal sleep group). We sampled saliva during the operational blocks over a 24-h period at day 55 of the mission and collected sleep actigraphy data during the entire mission in 10 participants. Sleep showed a biphasic split pattern with significantly unequal distributions of total sleep time (TST) and sleep efficiency (SE) between the two sleeping blocks, i.e., one long and one short sleep bout. Melatonin secretion showed no adjustment at the end of the mission to the watch standing blocks, following an endogenous circadian rhythm independent from the social zeitgebers with indications of a phase shift. Cortisol secretion however matched the biphasic work-sleep shift routine. Human physiology does not fully obey operational needs and there are differences in adjustment between melatonin and cortisol. A watch standing schedule that provides a balance between physiology and operationality still needs to be established. The potential adaptation effects of bright light therapy and melatonin supplementation should be investigated in future research. NEW & NOTEWORTHY The current study has a unique character due to the field context in which the data were collected. Data on long-term submarine missions are scarce and valuable in terms of operational and ecological validity. Moreover, the results are important both from a scientific and operational point of view, showing that human physiology does not fully obey operational needs and that there are differences in adjustment dependent from the type of circadian hormone.
AB - The submarine working and living environment is an isolated, confined, and extreme (ICE) environment where a continuous on-watch is required to fulfill the tactical objectives. The current study examined whether a physiological and behavioral adjustment to an operational watch standing scheme occurred in terms of hormonal secretion (i.e., melatonin and cortisol) and sleep during a 67-day undersea mission. The crew followed a strict scheme of watch-on blocks at 0:00–06:00 h and at 12:00–18:00 h (group 1, diurnal sleep group) or watch-on blocks at 06:00–12:00 h and 18:00–24:00 h (group 2, nocturnal sleep group). We sampled saliva during the operational blocks over a 24-h period at day 55 of the mission and collected sleep actigraphy data during the entire mission in 10 participants. Sleep showed a biphasic split pattern with significantly unequal distributions of total sleep time (TST) and sleep efficiency (SE) between the two sleeping blocks, i.e., one long and one short sleep bout. Melatonin secretion showed no adjustment at the end of the mission to the watch standing blocks, following an endogenous circadian rhythm independent from the social zeitgebers with indications of a phase shift. Cortisol secretion however matched the biphasic work-sleep shift routine. Human physiology does not fully obey operational needs and there are differences in adjustment between melatonin and cortisol. A watch standing schedule that provides a balance between physiology and operationality still needs to be established. The potential adaptation effects of bright light therapy and melatonin supplementation should be investigated in future research. NEW & NOTEWORTHY The current study has a unique character due to the field context in which the data were collected. Data on long-term submarine missions are scarce and valuable in terms of operational and ecological validity. Moreover, the results are important both from a scientific and operational point of view, showing that human physiology does not fully obey operational needs and that there are differences in adjustment dependent from the type of circadian hormone.
KW - ICE environment
KW - biphasic sleep
KW - circadian rhythm
KW - melatonin and cortisol
KW - submarine
UR - http://www.scopus.com/inward/record.url?scp=85128454742&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.00130.2021
DO - 10.1152/japplphysiol.00130.2021
M3 - Article
C2 - 35142558
AN - SCOPUS:85128454742
SN - 8750-7587
VL - 132
SP - 1069
EP - 1079
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 4
ER -