Interactive Screen-Based Activities Predict Worse Actigraphic Sleep Health That Night Among Adolescents

PURPOSE

To determine the micro-longitudinal effects of duration and timing of screen-based activities on sleep within and between adolescents.

METHODS

Daily survey and actigraphy data from the age 15 wave of the Future of Families and Child Wellbeing Study were analyzed using multilevel modeling. Four hundred seventy five adolescents provided three or more days of valid daily survey and nighttime sleep data.

RESULTS

Within-person results showed that on days when adolescents played video games more than their daytime average ± SE (1.3 ± 1.2 hours), sleep onset (6 ± 2 minutes, p < .01) and midpoint (4 ± 2 minutes, p < .02) were delayed for each additional hour of gaming. Between-person results showed that for each hour adolescents used screens to communicate with friends across the day, sleep onset was later (11 ± 3 minutes, p < .01), sleep midpoint was later (8 ± 3 minutes, p < .01), and sleep duration was shorter (-5 ± 2 minutes, p < .03). Adolescents who used screens to communicate with friends or play video games in the hour before bed had later sleep onset (30 ± 14 minutes, p < .03) and midpoint (25 ± 13 minutes, p < .05).

DISCUSSION

Among adolescents, passive screen usage such as browsing the Internet or watching videos may not affect sleep timing or duration, but limiting interactive screen-based activities could protect adolescent sleep health and well-being.

Actigraphic sleep dimensions and associations with academic functioning among adolescents

STUDY OBJECTIVES

There is mixed evidence regarding associations of sleep duration with academic functioning in adolescents and a lack of research on other sleep dimensions, particularly using objective sleep measures. We examined associations of multiple actigraphic sleep dimensions with academic functioning among adolescents.

METHODS

Data were from the sleep sub-study of the age 15 wave of the Future of Families and Child Wellbeing Study (n=774-782), a national, diverse sample of teens. Adolescents wore wrist-actigraphs for ~1 week and completed a survey reporting grades and school-related problems. Regression models assessed whether average sleep duration, timing, maintenance efficiency, and SD-variability were associated with self-reported academic functioning in cross-sectional analyses adjusted for demographic characteristics, depressive symptoms, and anxious symptoms.

RESULTS

Later sleep timing (hrs) and greater sleep variability (SD-hrs) were associated with poorer academic outcomes, including sleep onset variability with higher odds of receiving a D or lower (OR=1.29), sleep onset (β=-.07), sleep offset (β=-.08), and sleep duration variability (β=-.08) with fewer A grades, sleep offset with lower GPA (β=-.07), sleep offset (OR=1.11), sleep duration variability (OR=1.31), and sleep onset variability (OR=1.42) with higher odds of being suspended or expelled in the past two years, and sleep duration variability with greater trouble at school (β=.13). Sleep duration, sleep maintenance efficiency, and sleep regularity index were not associated with academic functioning.

CONCLUSION

Later sleep timing and greater sleep variability are risk factors for certain academic problems among adolescents. Promoting sufficient, regular sleep timing across the week may improve adolescent academic functioning.

Effects of a 1-hour per night week-long sleep extension in college students on cardiometabolic parameters, hydration status, and physical activity: A pilot study

OBJECTIVES

Short sleep duration is associated with poor physical health in college students. Few studies examine the effects of sleep extension on physical health in this population, who are susceptible to sleep loss. We examined health effects of a 1-week, 1-hour nightly sleep extension in college students.

METHODS

Twelve healthy undergraduate college students (83% female; age 20.2 ± 1.5years) completed a study consisting of sleeping typically for 1week ("Habitual"), then extending sleep by ≥1 hour/night during the second week ("Extension"). Sleep and physical activity actigraphy were collected throughout. Following each week, participants completed cardiometabolic assessments including a meal response and provided a urine sample for markers of hydration.

RESULTS

In Extension compared to Habitual, average sleep duration increased (mean change±SEM, +42.6 ± 15.1 minutes; p = .005), while subjective sleepiness (-1.8 ± 0.8 units; p = .040), systolic blood pressure (-6.6 ± 2.8 mmHg; p = .037), postprandial glucose area under the curve (-26.5 ± 10.2 mg/dL × h; p = .025) and time to baseline (-83.0 ± 46.4 minutes; p = .031) after the meal response, sedentary time (-44.3 ± 15.7 minutes; p = .018), and percentage of wake in moderate-to-vigorous activity (-0.89% ± 0.35%; p = .030) decreased. Participants who increased average sleep duration by ≥20 minutes (n = 9) were better hydrated according to urine osmolality (-187.0 ± 68.4 mOsm/kg; p = .026) and specific gravity (-0.01 ± 0.002 g/mL; p = .012) and had reduced odds of dehydration according to urine osmolality (≥800 mOsm/kg; -67%; OR=0.03; p = .035).

CONCLUSIONS

This pilot study's findings suggest that sleep extension may improve cardiometabolic functioning and hydration, and alter sedentary behavior and physical activity, in college students. Sleep extension may be employed to improve multiple aspects of health in this sleep-deprived population.

Entrainment to gradual vs. immediate 8-hour phase advance shifts with and without short-wavelength enriched polychromatic green light

OBJECTIVES

For optimal health and well-being the sleep episode and the circadian timing system should be properly aligned. We evaluated the effectiveness of different dynamic light and sleep/wake shift schedules for rapid circadian entrainment following an 8-hour advance of sleep.

METHODS

Forty-three healthy participants completed an 8-day inpatient protocol in which the 8-hour sleep episode was advanced by 8 hours. Participants were assigned to one of five conditions: (1) dim ambient WHITE light and GRADUAL shift in which the sleep episode was incrementally advanced over 5days; (2) dim GREEN, short-wavelength (∼504 nm) polychromatic light and GRADUAL shift; (3) dim WHITE light and SLAM shift, including an abrupt 8-hour advance on day 3 following an extended 32-hour wake episode; (4) GREEN light and SLAM shift; or (5) COMBINED (higher illuminance WHITE plus GREEN) light and modified SLAM shift with 2 short naps scheduled on the day prior to the abrupt advance. Phase shifts of the plasma dim light melatonin onset and sleep measures were compared to examine effects of protocol condition.

RESULTS

After 5days, the COMBINED light/modified SLAM shift condition showed larger phase advances of dim light melatonin onset (4.02 ± 1.13 hours) compared to the other 4 conditions (range 1.50 ± 0.96-2.83 ± 2.23 hours; p < .05) and resulted in increased REM sleep duration and fewer sleep disruptions.

CONCLUSIONS

Consideration of the type of shift and the illuminance and wavelength of light may assist in designing lighting countermeasures to sleep and circadian disruption, which has implications for jetlag, shiftwork, and circadian rhythm sleep disorders.

Recovery Sleep After Sleep Restriction Is Insufficient to Return Elevated Daytime Heart Rate and Systolic Blood Pressure to Baseline Levels

OBJECTIVE

Sleep restriction alters daytime cardiac activity, including elevating heart rate (HR) and blood pressure (BP). There is minimal research on the cumulative effects of sleep loss and the response after subsequent recovery sleep on HR and BP. This study examined patterns of HR and BP across baseline, sleep restriction, and recovery conditions using multiple daytime cardiac measurements.

METHODS

Participants (15 healthy men, mean [standard deviation] = 22.3 [2.8] years) completed an 11-day inpatient protocol with three nights of 10 hours/night baseline sleep opportunity, five sleep restriction nights (5-hour/night sleep opportunity), and two recovery nights (10-hour/night sleep opportunity). Resting HR and BP were measured every 2 hours during wake. Multilevel models with random effects for individuals examined daytime HR and BP across study conditions and days into the study.

RESULTS

Mean daytime HR was 1.2 (0.5) beats/min lower during sleep restriction compared with baseline ( p < .001). During recovery, HR was 5.5 (1.0) beats/min higher ( p < .001), and systolic BP (SBP) was 2.9 (1.1) mm Hg higher ( p = .009). When accounting for days into the study (irrespective of condition) and measurement timing across the day, HR increased by 7.6 beats/min and SBP increased by 3.4 mm Hg across the study period ( p < .001).

CONCLUSIONS

Our findings suggest that daytime HR and SBP increase after successive nights of sleep restriction, even after accounting for measurement time of day. HR and SBP did not recover to baseline levels after two recovery nights of sleep, suggesting that longer recovery sleep may be necessary to recover from multiple, consecutive nights of moderate sleep restriction.

Actigraphic Sleep Variability is Associated With Lower Positive Mood in Adolescents

PURPOSE

Poor sleep health is associated with lower positive mood in adolescents, and more variable sleep is associated with more negative mood. There is a lack of research on the associations between sleep variability and positive mood in adolescents. We investigated whether several types of sleep variability, measured with actigraphy, were associated with positive mood reported on a daily diary in adolescents.

METHODS

Data were collected from a substudy of the Year 15 wave of the Future of Families and Child Wellbeing Study (n = 580; 53% female, mean age ± standard deviation [SD] = 15.4 ± 0.5 years, range 14.7-17.7). Adolescents wore an actigraphy device (M ± SD = 5.6 ± 1.4 nights per adolescent, range: 3-10) and completed daily diaries (M ± SD = 5.5 ± 1.4 days per adolescent, range: 3-9) for ∼1 week, where they rated their levels of happiness and excitement during that day from 0 (not at all) to 4 (extremely). Happiness and excitement were averaged into "positive mood." Separate linear regression models assessed whether actigraphy-measured variability of sleep duration, onset, and offset (residual individual standard deviation, riSD), sleep regularity index, social jetlag, and free night catch-up sleep were associated with average positive mood per person. Analyses adjusted for age, birth sex, race/ethnicity, household income, and the primary caregiver's education level.

RESULTS

Greater variability in sleep duration (p = .011, β = -0.11) and lower sleep regularity index (p = .034, β = 0.09) were associated with lower ratings of positive mood. There were no other significant associations (p ≥ .10).

DISCUSSION

Variable and irregular sleep are associated with lower levels of positive mood in adolescence, which may increase the risk of poor emotional health in adulthood.

Worse sleep health predicts less frequent breakfast consumption among adolescents in a micro-longitudinal analysis

BACKGROUND

Poor self-reported sleep health has been linked to not consuming breakfast in adolescents, but it is unknown whether poor sleep measured objectively predicts next-day breakfast consumption within adolescents. We investigated within- and between-person associations of objectively measured sleep dimensions and subjective sleep quality with adolescent breakfast consumption.

METHODS

Data were collected from a micro-longitudinal substudy of the Year 15 wave of the Fragile Families and Child Wellbeing Study (n = 590). Adolescents wore an actigraphy device and completed daily diaries for ~ 1 week (M ± SD = 5.6 ± 1.4 nights per adolescent, range: 3-9), where they rated their sleep quality and reported whether they had eaten breakfast that day, with no specific definition of breakfast provided (M ± SD = 5.5 ± 1.4 days per adolescent, range: 3-9). Separate mixed models assessed whether actigraphy-measured sleep duration (linear and quadratic, sleep duration x sleep duration), timing, maintenance efficiency, and subjective quality predicted odds of breakfast consumption both within and between adolescents. Variability of sleep duration and timing (standard deviation per person), sleep regularity index (SRI), and social jetlag were tested as additional between-person predictors. Analyses with predictors other than sleep duration were adjusted for sleep duration.

RESULTS

Following nights when adolescents had shorter or longer sleep duration (p = .005; curvilinear association), later sleep onset, or later sleep midpoint (both p = .025) than their own usual, they had lower odds of consuming breakfast the next day (within-person associations). Adolescents who on average had later sleep onset (p = .013) or midpoint (p = .013) or who reported lower sleep quality (p = .011) had lower average odds of consuming breakfast (between-person associations). Adolescents with greater variability of sleep duration (p = .005), midpoint (p = .004), or offset (p < .001) had lower average odds of consuming breakfast (between-person associations). Sleep maintenance efficiency (within or between adolescents), SRI, and social jetlag were not associated with breakfast consumption (all p > .10).

CONCLUSIONS

Multiple dimensions of sleep health are associated with breakfast consumption, both within and between adolescents. Poor sleep and dietary behaviors in adolescence may negatively impact future metabolic health.

Secondhand smoke exposure is longitudinally associated with shorter parent-reported sleep duration during childhood

BACKGROUND

Secondhand smoke exposure has been cross-sectionally associated with worse sleep health outcomes in children and shorter sleep duration in adolescents.

OBJECTIVES

We assessed longitudinal and cross-sectional associations between secondhand smoke (SHS) exposure and shorter sleep duration in children from the Fragile Families and Child Wellbeing Study, a longitudinal birth cohort. We additionally examined whether associations would persist after controlling for potential confounders.

PARTICIPANTS

Mothers (n = 4898) were recruited using a stratified random sample of large United States cities and oversampling for nonmarital births.

MEASUREMENTS

Mothers were asked about whether they smoked during pregnancy, whether their child spent time with someone who is smoking, and their child's weekday sleep duration. Sociodemographic factors, asthma diagnosis, and bedtime routines were assessed as potential confounders. Data collected at ages 3, 5, and 9 years were analyzed using multivariable regression models (N = 1912; 51.6% boys).

RESULTS

SHS exposure at age 3 predicted 15.0 fewer minutes at age 5 (P = .001) and 12.3 fewer minutes at age 9 (P = .003). SHS exposure at age 9 was cross-sectionally associated with 14.4 fewer minutes of sleep duration at age 9 (P = .002). Findings persisted after controlling for potential confounders.

CONCLUSION

These results provide associational support for the hypothesis that SHS exposure may have long-term consequences for childhood sleep duration. Future studies should investigate the relationship between SHS exposure and shorter sleep duration using objective measurements of serum cotinine and sleep actigraphy and by exploring potential mechanisms.

0303 Heart Rate and Systolic Blood Pressure Increase During Experimental Sleep Restriction

Introduction

Experimental sleep restriction is associated with elevated daytime cardiac activity, including heart rate (HR) and blood pressure (BP). However, some studies have found changes in systolic (SBP) but not diastolic blood pressure (DBP) or found changes in neither. Although findings are mixed, there may be a dose-response effect of cumulative sleep loss on daytime cardiac activity, such that HR and BP increase above basal levels with additional nights of insufficient sleep. This study examined changes in cardiac activity during experimental sleep restriction.

Methods

We used multilevel models with random effects for individuals to analyze data from 15 healthy males (M=22.3 years old, SD=2.8) in an 11-day inpatient protocol consisting of three nights of 10-hour/night baseline sleep opportunity, five nights of sleep restriction (5-hour/night sleep opportunity), and then two recovery nights (10-hour/night sleep opportunity). HR and BP were measured approximately every two hours during wake.

Results

HR increased 0.75 beats/minute with each successive night of sleep restriction (SE=0.18, p&lt;0.001). HR was 5.13 beats/minute higher during the recovery condition than during baseline or sleep restriction (SE=1.05, p&lt;0.001). During sleep restriction only, HR was lower in the later morning and evening compared to the earliest morning timepoint of the day, F(10, 743)=10.44, p&lt;0.001. SBP increased 0.33 mmHg following each successive night of sleep restriction (SE=0.16, p=0.041); however, SBP was only marginally higher during the sleep restriction condition than during baseline (b=1.90, SE=1.09, p=0.082).

Conclusion

Our findings suggest that HR and SBP increase with each additional day of experimental sleep restriction, even after accounting for diurnal effects on HR and SBP. HR did not recover to baseline levels following a night of recovery sleep, suggesting that longer recovery sleep may be necessary to recover from a week of sleep restriction.

Support

Grant UL1TR000127 (Chang PI), Clinical and Translational Science Institute; College of Health and Human Development at Pennsylvania State University.

Validity of Actigraphy in Young Adults With Insomnia

Objective/Background: Actigraphy is an inexpensive and objective wrist-worn activity sensor that has been validated for the measurement of sleep onset latency (SOL), number of awakenings (NWAK), wake after sleep onset (WASO), total sleep time (TST), and sleep efficiency (SE) in both middle-aged and older adults with insomnia. However, actigraphy has not been evaluated in young adults. In addition, most previous studies compared actigraphy to in-lab polysomnography (PSG), but none have compared actigraphy to more ecologically valid ambulatory polysomnography.Participants: 21 young adults (mean age = 19.90 ± 2.19 years; n = 13 women) determined to have chronic primary insomnia through structured clinical interviews.Methods: Sleep diaries, actigraphy, and ambulatory PSG data were obtained over a single night to obtain measures of SOL, NWAK, WASO, time spent in bed after final awakening in the morning (TWAK), TST, and SE.Results: Actigraphy was a valid estimate of SOL, WASO, TST, and SE, based on significant correlations (r = 0.45 to 0.87), nonsignificant mean differences between actigraphy and PSG, and inspection of actigraphy bias from Bland Altman plots (SOL α = 1.52, WASO α = 7.95, TST α = -8.60, SE α = -1.38).Conclusions: Actigraphy was a valid objective measure of SOL, WASO, TST, and SE in a young adult insomnia sample, as compared to ambulatory PSG. Actigraphy may be a valid alternative for assessing sleep in young adults with insomnia when more costly PSG measures are not feasible.

Associations Between Sleep and Health-Risk Behaviors in a Rural Adolescent Population

INTRODUCTION

Insufficient sleep has been associated with engagement in a number of health-risk behaviors in adolescents, including substance use and sexual activity. Associations between sleep and health-risk behaviors in adolescents living in rural areas of the United States are not well investigated. In rural settings, adolescents' sleep patterns, lifestyle factors, and health-risk opportunities may differ from those of urban adolescents, making the independent study of sleep and health behavior associations necessary.

METHOD

This study examined data from the Rural Adolescent Health Survey (N = 322) administered in rural North Dakota.

RESULTS

Rural adolescents who reported engaging in smoking, alcohol use, or drug use slept significantly less than adolescents who did not report engaging in these activities.

DISCUSSION

Sleep was not associated with chewing tobacco use or risky sexual activity, which may reflect an effect of rural cultural values on sleep and health-risk behavior associations.