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Circadian alignment of rest-activity rhythms is an essential biological process that may be vulnerable to misalignment in critically ill patients. We evaluated circadian rest-activity rhythms in critically ill patients and their association with baseline (e.g. age) and clinical (e.g. mechanical ventilation status) variables, along with intensive care unit light-dark cycles. Using wrist actigraphy, we collected 48-hr activity and light exposure data from critically ill patients in a tertiary care medical intensive care unit. We evaluated circadian rest-activity rhythms using COSINOR and non-parametric circadian rhythm analysis models, and stratified these data across baseline and clinical variables. We used linear regression to evaluate the association of circadian rest-activity and light-dark exposure rhythms. In COSINOR and non-parametric circadian rhythm analysis analyses, the 34 medical intensive care unit patients completing 48-hr actigraphy recordings exhibited mean MESOR (mean activity levels of a fitted curve) and amplitudes of 0.50 ± 0.32 and 0.20 ± 0.19 movements per 30-s epoch, with high interdaily variability. Patients who were older, mechanically ventilated, sedated, restrained and with higher organ failure scores tended to exhibit greater circadian rest-activity misalignment, with three of 34 (9%) patients exhibiting no circadian rhythmicity. Circadian light-dark exposure misalignment was observed as well and was associated with rest-activity misalignment (p = 0.03). Critically ill patients in our MICU experienced profound circadian rest-activity misalignment, with mostly weak or absent rhythms, along with circadian light-dark exposure misalignment. Potentially modifiable factors contributing to rest-activity misalignment (i.e. mechanical ventilation, restraints, low daytime light levels) highlight possible targets for future improvement efforts.

Objective: Examine associations between a range of sleep problems and academic performance in a national sample of collegiate athletes. Participants: Data were obtained from the National College Health Assessment of US college/university students from 2011-2014 (N = 8,312 collegiate athletes). Methods: Univariate comparisons for all sleep variables and demographics were stratified across GPA, using one-way ANOVA for continuous variables and chi-square for categorical variables. Multinomial logistic regression models, with GPA as outcome (reference = A) and sleep variable as predictor, were examined and adjusted for age, sex, and survey year. Ordinal regression examined a 1-level change in GPA associated with each sleep variable, adjusted for covariates. Results: Sleep difficulty was associated with increased likelihood of B/C averages. Initial-insomnia was associated with increased likelihood of B/C, and D/F averages. Tiredness was associated with increased likelihood of B/C, and D/F averages. Conclusions: Sleep problems are highly prevalent and associated with poorer academic performance in collegiate athletes.

The present study investigated the roles birthplace and acculturation play in sleep estimates among Hispanic/Latino population at the US–Mexico border. Data were collected in 2016, from N = 100 adults of Mexican descent from the city of Nogales, AZ, at the US–Mexico border. Sleep was assessed with the Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index categorized as none, mild, moderate, and severe, and Multivariable Apnea Prediction Index (MAP) categorized as never, infrequently, and frequently. Acculturation was measured with the Acculturation Rating Scale for Mexican-Americans II (ARSMA-II). The sample consisted of majority Mexican-born (66%, vs. born in the USA 38.2%). Being born in the USA was associated with 55 fewer minutes of nighttime sleep (p =.011), and 1.65 greater PSQI score (p =.031). Compared to no symptoms, being born in the USA was associated with greater likelihood of severe difficulty falling asleep (OR = 8.3, p =.030) and severe difficulty staying asleep (OR = 11.2, p =.050), as well as decreased likelihood of breathing pauses during sleep (OR = 0.18, P =.020). These relationships remained significant after Mexican acculturation was entered in these models. However, greater Anglo acculturation appears to mediate one fewer hour of sleep per night, poorer sleep quality, and reporting of severe difficulty falling asleep and staying asleep. Among individuals of Mexican descent, being born in the USA (vs Mexico) is associated with about 1 hour less sleep per night, worse sleep quality, more insomnia symptoms, and less mild sleep apnea symptoms. These relationships are influenced by acculturation, primarily the degree of Anglo rather than the degree of Mexican acculturation. [ABSTRACT FROM AUTHOR]

STUDY PURPOSE:The integration of methods to assess daytime physical activity (PA) and sedentary behavior (SB) and nighttime sleep would allow the evaluation of 24-hour daily activity using a single device. Accelerometer devices used to assess daytime PA have not been substantially validated to evaluate sleep. The objective of this study was to use polysomnography (PSG) to validate a commonly used PA accelerometer worn on both wrists and the hip. METHODS:Seventeen participants (50-75years) completed a single-night in-home PSG recording while concurrently wearing 3 PA accelerometers. Accelerometer devices were worn on each wrist and the hip. Total sleep time (TST), sleep efficiency (SE), and wake after sleep onset (WASO) were compared for each device against PSG. Correlation coefficients estimated measurement agreement. Paired t tests and Bland-Altman plots assessed measurement differences. RESULTS:Between PSG and devices, mean TST ranged from 361.6 to 403.2minutes. Mean SE estimates ranged from 86.9% to 96.9%. Mean WASO estimates ranged from 12 to 51.2minutes. For TST, SE, and WASO hip estimates differed significantly from PSG estimates (paired t tests, TST: P=.03, SE: P

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