0289 What is the Optimal Duration to Sleep in on Weekends?

Abstract Introduction Most individuals in the workforce exhibit differing sleep/wake patterns between work days and weekends. Work days are typically characterized by shorter and earlier sleep. On weekends, sleep debt is repaid by sleeping later and longer, often due to evening events. While social jet-lag (the mismatch in work vs. free sleep timing) is associated with poor health outcomes, repaying sleep debt is beneficial to health. The degree to which individuals should sleep in on weekends is currently unknown. Methods We used a mathematical model of human sleep/wake timing, which has been validated for predicting sleep/wake patterns in a variety of field/lab conditions. Sleep timing constraints are inputs, and the model generates predicted sleep/wake patterns and alertness levels. We simulated a traditional 7-day work week, with 7am rise times on week days. Inter-individual differences in chronotype were modeled by varying intrinsic circadian period. The model was applied to two conditions: (i) free choice of sleep onset times on weekends; or (ii) late nights on weekends (2am bedtime). Weekend rise time was systematically varied to optimize predicted daytime alertness. Results Optimal weekend rise times varied as a function of chronotype. With free choice sleep onset times, the model predicted optimal rise time was later for late types than early types, ranging from 7:20 to 8:40am across individuals. Sleeping later than optimal was associated with poorer performance due to misaligned circadian phase. The same trend was observed in the late-night condition, but with later optimal rise times, ranging from 8:30 to 9:50am. Conclusion Although individuals should maintain a consistent sleep/wake pattern on all days of the week, they often do not, due to work or social commitments. Within real-world constraints, we provided the first objective recommendations for sleep timing on the weekend, finding a compromise between repaying sleep debt and avoiding circadian misalignment. Support N/A

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Timing of human sleep: recovery process gated by a circadian pacemaker

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1984.246.2.r161 ◽

1984 ◽

Vol 246 (2) ◽

pp. R161-R183 ◽

Cited By ~ 135

Author(s):

S. Daan ◽

D. G. Beersma ◽

A. A. Borbely

Keyword(s):

Sleep Deprivation ◽

Sleep Onset ◽

Recovery Process ◽

Bed Rest ◽

Circadian Pacemaker ◽

Phase Dependence ◽

Circadian Phase ◽

Sleep Timing ◽

Human Sleep ◽

Partial Sleep Deprivation

A model for the timing of human sleep is presented. It is based on a sleep-regulating variable (S)--possibly, but not necessarily, associated with a neurochemical substance--which increases during wakefulness and decreases during sleep. Sleep onset is triggered when S approaches an upper threshold (H); awakening occurs when S reaches a lower threshold (L). The thresholds show a circadian rhythm controlled by a single circadian pacemaker. Time constants of the S process were derived from rates of change of electroencephalographic (EEG) power density during regular sleep and during recovery from sleep deprivation. The waveform of the circadian threshold fluctuations was derived from spontaneous wake-up times after partial sleep deprivation. The model allows computer simulations of the main phenomena of human sleep timing, such as 1) internal desynchronization in the absence of time cues, 2) sleep fragmentation during continuous bed rest, and 3) circadian phase dependence of sleep duration during isolation from time cues, recovery from sleep deprivation, and shift work. The model shows that the experimental data are consistent with the concept of a single circadian pacemaker in humans. It has implications for the understanding of sleep as a restorative process and its timing with respect to day and night.

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086 Sleep midpoint after job loss predicts breakfast skipping patterns

SLEEP ◽

10.1093/sleep/zsab072.085 ◽

2021 ◽

Vol 44 (Supplement_2) ◽

pp. A36-A36

Author(s):

Leah Callovini ◽

Gaby Gubka ◽

Candace Mayer ◽

Darlynn Rojo-Wissar ◽

David Glickenstein ◽

...

Keyword(s):

Job Loss ◽

Activity Patterns ◽

Sleep Onset ◽

Daily Routine ◽

Cross Sectional ◽

Circadian Phase ◽

Breakfast Skipping ◽

Occupational Transitions ◽

The Relationship ◽

Significant Covariates

Abstract Introduction Few studies have examined circadian phase after job loss, an event that upends daily routine. It is common that a daily routine begins with the consumption of breakfast, and breakfast behavior may contribute to health status in adults. Therefore, we sought to examine whether a later midpoint of sleep was associated with breakfast skipping among adults whose schedules were no longer dictated by employment. Methods Data were obtained from the Assessing Daily Activity Patterns Through Occupational Transitions (ADAPT) study. The sample of 155 participants had involuntarily lost their jobs in the last 90 days. Both cross-sectional and 18-month longitudinal analyses assessed the relationship between sleep midpoint after job loss and current and later breakfast skipping. Assessment periods were 14 days. Sleep was measured via actigraphy, and breakfast skipping was measured via daily diary (1 = had breakfast; 0 = did not have breakfast). The midpoint of sleep was calculated as the circular center based on actigraphy sleep onset and offset times. Results The midpoint of sleep at baseline was negatively associated with breakfast consumption at baseline (B = -.09, SE = .02, p = .000). Also, a later midpoint was associated with breakfast skipping over the next 18 months (estimate = -.08; SE = .02; p = .000). Prospective findings remained significant when adjusting for gender, ethnicity, age, perceived stress, body mass index (BMI), education, and reemployment over time. Education (estimate = 14.26, SE = 6.23, p < .05) and BMI (estimate = -.51, SE = .25, p < .05) were the only significant covariates. No other sleep indices predicted breakfast behavior cross-sectionally or prospectively. Conclusion Consistent with research in adolescents, unemployed adults with a later circadian phase are more likely to skip breakfast more often. Breakfast skipping was also associated with higher BMI. Taken together, these findings provide support for the future testing of sleep/wake scheduling interventions to modify breakfast skipping and potentially mitigate weight gain after job loss. Support (if any) #1R01HL117995-01A1

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Longitudinal association of actigraphy-assessed sleep with physical growth in the first 6 months of life

SLEEP ◽

10.1093/sleep/zsab243 ◽

2021 ◽

Author(s):

Xiaoyu Li ◽

Sebastien Haneuse ◽

Michael Rueschman ◽

Emily R Kaplan ◽

Xinting Yu ◽

...

Keyword(s):

Sleep Duration ◽

Sleep Onset ◽

Specific Weight ◽

Estimating Equation ◽

Physical Growth ◽

Term Infants ◽

Rapid Changes ◽

Wake Patterns ◽

Longitudinal Association ◽

Nighttime Sleep

Abstract Study Objectives Suboptimal sleep is associated with obesity and its sequelae in children and adults. However, few studies have examined the association between sleep and physical growth in infants who experience rapid changes in sleep/wake patterns. We examined the longitudinal association of changes in objectively assessed sleep/wake patterns with changes in growth between ages 1 and 6 months. Methods We studied 298 full-term infants in the longitudinal Rise & SHINE cohort study. Changes from 1 and 6 months in nighttime sleep duration, wake after sleep onset (WASO), and number of waking bouts ≥5 min were assessed using ankle actigraphy. Overweight was defined as age- and sex-specific weight for length ≥95th percentile. Generalized estimating equation analyses adjusted for infants′ and mothers′ characteristics. Results The mean (SD) birth weight was 3.4 (0.4) kg; 48.7% were boys. In multivariable adjusted models, each 1-h increase in nighttime sleep duration between months 1 and 6 was associated with a 26% decrease in the odds of overweight from 1 to 6 months (odds ratio [OR] = 0.74; 95% confidence interval [CI, 0.56, 0.98]). Each 1-unit decrease in number of waking bouts was associated with a 16% decrease in the odds of overweight (OR = 0.84; 95% CI [0.72, 0.98]). Changes in WASO were not associated with the odds of overweight. Conclusions Greater increases in nighttime sleep duration and more consolidation of nighttime sleep were associated with lower odds of overweight from 1 to 6 months. Adverse sleep patterns as early as infancy may contribute to excess adiposity.

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The COVID-19 Lockdown and Changes in Routine-Oriented Lifestyle Behaviors and Symptoms of Depression, Anxiety, and Insomnia in South Africa

Journal of Physical Activity and Health ◽

10.1123/jpah.2020-0863 ◽

2021 ◽

pp. 1-12

Author(s):

Jonathan P. Davy ◽

Karine Scheuermaier ◽

Laura C. Roden ◽

Candice J. Christie ◽

Alison Bentley ◽

...

Keyword(s):

Online Survey ◽

Lifestyle Behaviors ◽

Exercise Time ◽

South Africans ◽

Symptoms Of Depression ◽

Sleep Timing ◽

Sleep Debt ◽

Males And Females ◽

The Impact ◽

Habitual Routines

Background: The authors assessed the impact of lockdown in response to the COVID-19 pandemic on routine-oriented lifestyle behaviors and symptoms of depression, anxiety, and insomnia in South Africans. Methods: In this observational study, 1048 adults (median age = 27 y; n = 767 females; n = 473 students) responded to an online survey on work, exercise, screen, alcohol, caffeine and sleep behaviors, depression, anxiety, and insomnia before and during lockdown. Comparisons were made between males and females, and students and nonstudents. Results: During lockdown, males reported larger reductions in higher intensity exercise and alcohol use than females, while depressive symptoms increased more among females, more of whom also reported poorer sleep quality. Students demonstrated larger delays in work and sleep timing, greater increases in sitting, screen, sleep duration, napping, depression and insomnia and larger decreases in work hours, exercise time, and sleep regularity compared with nonstudents. Conclusions: Students experienced more changes in their routine-oriented behaviors than nonstudents, coupled with larger increases in depression and insomnia. The dramatic change in their work and sleep timing suggests habitual routines that are at odds with their chronotype, with their sleep changes during lockdown likely reflecting “catch-up” sleep in response to accumulated sleep debt under usual routines.

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Does Chronotype explain Daily Timing of Music Behaviors?

10.31234/osf.io/h7235 ◽

2021 ◽

Author(s):

Shannon Wright ◽

Caroline Palmer

Keyword(s):

Social Interaction ◽

Daily Activity ◽

Music Performance ◽

Sleep Onset ◽

Time Of Day ◽

Sleep Diary ◽

Sleep Habits ◽

Sleep Timing ◽

Music Making ◽

Daily Changes

We addressed how circadian rhythms influence daily musical activities of performing musicians, who exhibit fine temporal control. Music performances often occur in the evening and late at night; evidence suggests that composing musicians tend to be later chronotypes than non-composing musicians. However, chronotype and daily music-making in performing musicians have yet to be investigated. The current study examined chronotype in actively practicing and/or performing musicians and non-musicians, and whether it was related to the daily timing of music performance. To test influences of daily changes due to the global COVID-19 pandemic, disruptions to musical, athletic, social, and sleep habits were also measured. Performing musicians, active (practicing but non-performing) musicians, inactive musicians, and non-musicians, residing in Canada, completed a 7-day online daily activity and sleep diary in Summer 2020. There were more evening chronotypes than morning chronotypes in the sample. Active/performing musicians tended to be earlier chronotypes than all other groups. Musicians' chronotype, but not nightly sleep timing, predicted the time of day that musicians made music: Late chronotypes made music later in the day and early chronotypes made music earlier in the day. Music performance and practice amount decreased during the COVID-19 period, but the daily timing of these activities did not change. All participants reported later sleep onset during the COVID-19 period; the amount of social interaction decreased during the COVID-19 period, while exercise increased for some and decreased for others. No changes in the daily timing of exercise, social interaction, or morning wake-up were reported. These findings suggest that performing musicians may be slightly earlier chronotypes than non-performing musicians and non-musicians, despite music performances often occurring in the evening. Chronotype was related to the time of day of music-making independent of nightly sleep timing, suggesting that times of day for making music reflect an individual's circadian rhythm.

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A single dose of alcohol does not meaningfully alter circadian phase advances and phase delays to light in humans

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00001.2016 ◽

2016 ◽

Vol 310 (8) ◽

pp. R759-R765 ◽

Cited By ~ 8

Author(s):

Helen J. Burgess ◽

Muneer Rizvydeen ◽

Louis F. Fogg ◽

Ali Keshavarzian

Keyword(s):

Single Dose ◽

Light Pulse ◽

Bright Light ◽

Phase Shifts ◽

Final Phase ◽

Circadian Timing ◽

Circadian Phase ◽

Sleep Episode ◽

Late Night ◽

Laboratory Session

Central circadian timing influences mental and physical health. Research in nocturnal rodents has demonstrated that when alcohol is consumed, it reaches the central hypothalamic circadian pacemaker (suprachiasmatic nuclei) and can directly alter circadian phase shifts to light. In two separate studies, we examined, for the first time, the effects of a single dose of alcohol on circadian phase advances and phase delays to light in humans. Two 23-day within-subjects placebo-controlled counterbalanced design studies were conducted. Both studies consisted of 6 days of fixed baseline sleep to stabilize circadian timing, a 2-day laboratory session, a 6-day break, and a repeat of 6 days of fixed sleep and a 2-day laboratory session. In the phase advance study ( n = 10 light drinkers, 24–45 yr), the laboratory sessions consisted of a baseline dim light phase assessment, sleep episode, alcohol (0.6 g/kg) or placebo, 2-h morning bright light pulse, and final phase assessment. In the phase-delay study ( n = 14 light drinkers, 22–44 yr), the laboratory sessions consisted of a baseline phase assessment, alcohol (0.8 g/kg) or placebo, 2-h late night bright light pulse, sleep episode, and final phase assessment. In both studies, alcohol either increased or decreased the observed phase shifts to light (interaction P ≥ 0.46), but the effect of alcohol vs. placebo on phase shifts to light was always on average smaller than 30 min. Thus, no meaningful effects of a single dose of alcohol vs. placebo on circadian phase shifts to light in humans were observed.

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Do Parental Expectations Play a Role in Children's Sleep and Mothers' Distress? An Exploration of the Goodness of Fit Concept in 54 Mother-Child Dyads

Sleep Disorders ◽

10.1155/2011/104832 ◽

2011 ◽

Vol 2011 ◽

pp. 1-8 ◽

Cited By ~ 2

Author(s):

Helene Werner ◽

Oskar G. Jenni

Keyword(s):

Goodness Of Fit ◽

Sleep Onset ◽

Parental Expectations ◽

Onset Time ◽

Kindergarten Children ◽

Parental Distress ◽

Time In Bed ◽

Falling Asleep ◽

Wake Patterns ◽

Children’S Sleep

This study describes parental expectations for sleep-wake patterns in healthy kindergarten children and explores their relation to children’s sleep quality and parental distress. Data analysis of 54 mother-child dyads (age range of the children: 4–7 years) indicated that parental expectations for children’s sleep-wake patterns differ between scheduled and free days and depend on children’s chronotype. Mothers of children with late chronotype showed less adequate expectations for children’s sleep onset time than mothers of children with early chronotype (e.g., morning types). Furthermore, children of mothers with less adequate expectations for children’s sleep onset time on scheduled days had longer settling periods during which sleep rituals may take place (r=0.31,P≤0.05), spent more time in bed than they actually sleep (r=0.35,P≤0.01), and had more frequently difficulties falling asleep (r=0.33,P≤0.01). However, less adequate expectations for children’s sleep onset time were not associated with parental distress (P>0.05). We conclude that parental expectations about their children’s sleep play a key role in understanding normal and abnormal sleep during childhood.

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Circadian tau differences and rhythm associations in delayed sleep–wake phase disorder and sighted non-24-hour sleep–wake rhythm disorder

SLEEP ◽

10.1093/sleep/zsaa132 ◽

2020 ◽

Author(s):

Gorica Micic ◽

Nicole Lovato ◽

Sally A Ferguson ◽

Helen J Burgess ◽

Leon Lack

Keyword(s):

Circadian Rhythm ◽

Core Body Temperature ◽

Sleep Onset ◽

Phase Relationship ◽

Biological Rhythms ◽

Circadian Phase ◽

Behavioral Rhythm ◽

Rhythm Disorder ◽

Dim Light ◽

Delayed Sleep

Abstract Study Objectives We investigated biological and behavioral rhythm period lengths (i.e. taus) of delayed sleep–wake phase disorder (DSWPD) and non-24-hour sleep–wake rhythm disorder (N24SWD). Based on circadian phase timing (temperature and dim light melatonin onset), DSWPD participants were dichotomized into a circadian-delayed and a circadian non-delayed group to investigate etiological differences. Methods Participants with DSWPD (n = 26, 17 m, age: 21.85 ± 4.97 years), full-sighted N24SWD (n = 4, 3 m, age: 25.75 ± 4.99 years) and 18 controls (10 m, age: 23.72 ± 5.10 years) participated in an 80-h modified constant routine. An ultradian protocol of 1-h “days” in dim light, controlled conditions alternated 20-min sleep/dark periods with 40-min enforced wakefulness/light. Subjective sleepiness ratings were recorded prior to every sleep/dark opportunity and median reaction time (vigilance) was measured hourly. Obtained sleep (sleep propensity) was derived from 20-min sleep/dark opportunities to quantify hourly objective sleepiness. Hourly core body temperature was recorded, and salivary melatonin assayed to measure endogenous circadian rhythms. Rhythm data were curved using the two-component cosine model. Results Patients with DSWPD and N24SWD had significantly longer melatonin and temperature taus compared to controls. Circadian non-delayed DSWPD had normally timed temperature and melatonin rhythms but were typically sleeping at relatively late circadian phases compared to those with circadian-delayed DSWPD. Conclusions People with DSWPD and N24SWD exhibit significantly longer biological circadian rhythm period lengths compared to controls. Approximately half of those diagnosed with DSWPD do not have abnormally delayed circadian rhythm timings suggesting abnormal phase relationship between biological rhythms and behavioral sleep period or potentially conditioned sleep-onset insomnia.

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