Chronotype and self-reported sleep, alertness, and mental health in U.S. sailors

Abstract

Service members are at risk for sleep and psychological conditions affecting their readiness. Chronotype (“morningness” or “eveningness”) is strongly associated with sleep, health and performance. The objective of this study was to examine associations between validated measures of chronotype and sleep quality, daytime functioning, alertness, and symptoms of depression, anxiety, and post-traumatic stress disorder (PTSD) in US service members (n = 298). Although predominantly young males (who skew toward eveningness in civilian populations), these Sailors skewed toward morningness (35.6% morning, 51.3% intermediate). Eveningness was associated with symptoms of depression and post-traumatic stress disorder (PTSD) (P < 0.01), less time in bed (P < 0.05), more sleep disruption (P < 0.01), and poorer daytime functioning and alertness (P < 0.05). Evening types were less likely to consider sleep important for performance (P < 0.05). To maximize service member readiness, schedules should be aligned with endogenous rhythms, whenever possible, and evening chronotypes may benefit from targeted interventions. Chronotype should be examined alongside health and readiness in service members.

Exploratory Study on the Associations between Lifetime Post-Traumatic Stress Spectrum, Sleep, and Circadian Rhythm Parameters in Patients with Bipolar Disorder

“…In the present study, for the first time we report the association between ET and higher lifetime post-traumatic stress spectrum symptoms, more disrupted sleep and circadian rhythmicity with respect to MT and NT, among a sample of patients with BD. Our results are consistent with previous findings showing how eveningness was associated with higher PTSS in subjects exposed to potentially traumatic events [ 27 , 47 ]. Likewise, associations between eveningness and symptoms that are related to PTSS have been reported, such as increased tendency to maladaptive behaviors [ 48 , 49 ], propensity to experience nightmares [ 50 , 51 ], and lower levels of resilience to stressful events [ 52 ].…”

Hybrid effectiveness-implementation study of two novel spectrally engineered lighting interventions for shiftworkers on a high-security watchfloor

“…Mixed models with participant as a random factor, condition as a fixed factor (baseline, SW+, and SW-), and sex as a covariate were used for all continuous and ordinal outcome measures of interest, with Bonferroni adjustments for post hoc tests. Chronotype ( Supplementary Table S1 ) was considered as a factor, but no main effects of chronotype on main outcomes of interest were found, thus it was not included in any model; we did, however, replicate previous findings in military samples where, contrary to expectations given the relative young age and predominantly male sample, chronotype tended to skew towards morningness [ 75 , 76 ].…”

Pushing the frontiers of military medical excellence: updates, progress and future needs

“…The effect of the military on the mental health of soldiers is not a temporary one, but can have longterm deleterious effects even long after they have left the military, impacting on quality of life. To tackle the negative effects of sleep deprivation or poor sleep quality on the mental health well-being of soldiers, Harrison et al [23] studied the chronotype profile of U.S. sailors, and suggested aligning military schedules with endogenous circadian rhythms to optimise performance. On the other hand, Baig et al [24] found that quetiapine monotherapy can increase engagement in trauma-focused psychotherapy, given that fluoxetine, the alternative pharmacologic treatment for PTSD, has an extended onset of action and can exacerbate post-concussion syndrome in mild TBI.…”