Sleep extension and cardiometabolic health: what it is, possible mechanisms and real-world applications.

Short sleep duration is associated with heightened cardiometabolic disease risk and has reached epidemic proportions among children, adolescents and adults. Potential mechanisms underlying this association are complex and multifaceted, including disturbances in circadian timing, food intake and appetitive hormones, brain regions linked to control of hedonic eating, physical activity, an altered microbiome and impaired insulin sensitivity. Sleep extension, or increasing total sleep duration, is an emerging and ecologically relevant intervention with significant potential to advance our understanding of the mechanisms underlying the association between short sleep duration and the risk of cardiometabolic disease. If effective, sleep extension interventions have potential to improve cardiometabolic health across the lifespan. Existing data show that sleep extension is feasible and might have potential cardiometabolic health benefits, although there are limitations that the field must overcome. Notably, most existing studies are short term (2-8 weeks), use different sleep extension strategies, analyse a wide array of cardiometabolic health outcomes in different populations and, frequently, lack adequate statistical power, thus limiting robust scientific conclusions. Overcoming these limitations will require fully powered, randomized studies conducted in people with habitual short sleep duration and existing cardiometabolic risk factors. Additionally, randomized controlled trials comparing different sleep extension strategies are essential to determine the most effective interventions. Ongoing and future research should focus on elucidating the potential cardiometabolic health benefits of sleep extension. Such studies have high potential to generate crucial knowledge with potential to improve health and quality of life for those struggling with short sleep duration.

Sleepy without stimulation: subjective and objective sleepiness in actigraphy-verified natural short sleepers.

Natural short sleepers (NSS)-individuals who report minimal sleepiness or daytime dysfunction despite habitually sleeping less than the recommended amount (i.e., <7 h)-are a focus of growing interest in sleep research. Yet, the predominance of research on NSS has relied on subjective reports of functionality. The present study examined subjective and objective sleepiness among actigraphy-verified NSS in comparison with recommended (7-9 h/day) length sleepers (RLS) who reported similarly minimal daytime dysfunction. The study tested the hypothesis that under conditions of low environmental stimulation, NSS have increased risk of drowsiness and sleep onset, regardless of perceived alertness. The NSS and RLS groups were identified via screening and verified with a 14 day assessment with actigraphy, sleep diaries, and morning ratings of sleep restoration. In-laboratory resting electroencephalography (EEG) data were analysed using a computerised EEG-based algorithm (Vigilance Algorithm Leipzig; VIGALL) to classify second-by-second changes in objective sleepiness ranging from cognitively active alertness to sleep onset. Results demonstrated that NSS exhibited significantly higher drowsiness and sleep onset ('microsleeps') across 15 min of resting EEG despite perceptions of lower subjective sleepiness compared to RLS. Findings suggest that irrespective of perceived sleep restoration and alertness, NSS appear to be at high risk of objective sleepiness that is rapidly unmasked under conditions of low environmental stimulation. Such apparent discrepancy between subjective and objective sleepiness has potentially important public health implications. Future research directions, including tests of mechanisms and tailored sleep extension intervention, are discussed.

Short sleep duration and interest in sleep improvement in a multi-ethnic cohort of diverse women participating in a community-based wellness intervention: an unmet need for improvement.

BACKGROUND: Disparities in sleep duration are a modifiable contributor to increased risk for cardiometabolic disorders in communities of color. We examined the prevalence of short sleep duration and interest in improving sleep among a multi-ethnic sample of women participating in a culturally tailored wellness coaching program and discussed steps to engage communities in sleep health interventions. METHODS: Secondary analysis of data from a randomized trial were used. The wellness coaching trial utilized a Community-Based Participatory Research (CBPR) approach. Data were from the baseline survey and baseline wellness coaching notes. Short sleep duration was defined as < 7 h of self-reported sleep. Participants were prompted to set a goal related to healthy eating/physical activity and had the opportunity to set another goal on any topic of interest. Those who set a goal related to improving sleep or who discussed a desire to improve sleep during coaching were classified as having an interest in sleep improvement. Analyses utilized multivariable models to evaluate factors contributing to short sleep and interest in sleep improvement. We present our process of discussing results with community leaders and health workers. RESULTS: A total of 485 women of color participated in the study. Among these, 199 (41%) reported short sleep duration. In adjusted models, Blacks/African Americans and Native Hawaiians/Pacific Islanders had higher odds of reporting < 7 h of sleep than Hispanics/Latinas. Depression symptoms and self-reported stress management scores were significantly associated with short sleep duration. Interest in sleep improvement was noted in the wellness coaching notes of 52 women (10.7%); sleep was the most common focus of goals not related to healthy eating/physical activity. African Immigrants/Refugees and African Americans were less likely to report interest in sleep improvement. Community leaders and health workers reported lack of awareness of the role of sleep in health and discussed challenges to obtaining adequate sleep in their communities. CONCLUSION: Despite the high prevalence of short sleep duration, interest in sleep improvement was generally low. This study highlights a discrepancy between need and interest, and our process of community engagement, which can inform intervention development for addressing sleep duration among diverse women.

Associations of Anxiety, Insomnia, and Physical Activity during the COVID-19 Pandemic.

PURPOSE: Anxiety, insomnia, and physical activity (PA) are interrelated, but the bi-directional relationships between these three variables are not well understood. Less is known of these relationships in settings of disrupted daily activities and acute stress. This study aimed to characterize and examine relationships between insomnia, anxiety, and PA throughout the first year of the COVID-19 pandemic, when many lifestyle behaviors were disrupted. METHODS: Participants comprised a convenience sample of 204 adults (55.4% female; 43.85 ± 15.85 years old) who completed the Generalized Anxiety Disorder Questionnaire (GAD-7), Insomnia Severity Index (ISI), and the International Physical Activity Questionnaire (IPAQ) at three time points through the first year of the COVID-19 pandemic. A cross-lagged panel model was used to evaluate these variables' concurrent, autoregressive, and cross-lagged relationships across time. Follow-up dynamic panel modeling using maximum likelihood and structural equation modeling was employed. RESULTS: Approximately 64% of participants reported their work/occupation as affected by the pandemic. At baseline, associations between anxiety and insomnia were observed (ß-coefficient: 15.87; p < 0.001). Insomnia was a positive future predictor of anxiety (ISI time point 2: 7.9 ± 5.6 points; GAD-7 at time point 3: 4.1 ± 4.2 points; ß-coefficient: 0.16; p < 0.01). No associations were observed between PA and anxiety or insomnia (all p > 0.05). CONCLUSIONS: Insomnia and anxiety were interrelated, and effects were cross-lagged. These data can inform future work focused on improving anxiety in settings of acute stress and disruptions to daily life, such as changes in occupational structure and stability. Specifically, targeting sleep parameters may be of interest to elicit downstream positive health behaviors.

Interest and use of mental health and specialty behavioral medicine counseling in US primary care patients.

BACKGROUND: Counseling interventions have the potential to improve health and quality of life for primary care patients, but there are few studies describing the interest in and utilization of counseling among this patient population in the USA. PURPOSE: The purpose of the study was to evaluate interest in mental health and specialty behavioral medicine counseling and predictors of utilization over 1 year among US primary care patients. METHOD: Participants in this two-survey longitudinal study included 658 primary care patients in an urban US academic medical center (461 females, age M = 51.05, SD = 15.46 years). Retention rate was 61.2% at survey 2. Patient demographics, depression, anxiety, and interest in counseling services were assessed through a survey mailed 1 week following an outpatient appointment. Respondents to survey 1 were re-contacted 1 year later to assess. Interest and use of the following counseling services were evaluated in the relevant subgroups: mental health (the entire sample and patients with elevated anxiety and/or depression), health/lifestyle (overweight and obese participants), smoking cessation (current and occasional smokers), and pain management (participants with elevated daily pain ratings). RESULTS: At survey 1, 45.7% of the sample reported interest in mental health counseling, and 58.9% of the sample reported interest in behavioral medicine counseling. Among overweight or obese participants, 59.9% were interested in health/lifestyle counseling. Among smokers, 55.3% were interested in smoking cessation, and among participants with chronic pain, 33.8% were interest in pain management. Rates of utilization of services at survey 2 were 21.3% for mental health, 7.7% for health/lifestyle, 6.7% for smoking cessation, and 6.6% for pain management. Interest in receiving services at survey 1 was the strongest predictor of utilization. CONCLUSION: Results demonstrate high interest but low utilization over 1 year among US primary care patients. Identifying patients interested in counseling services and reducing barriers may help facilitate receipt of services for those with interest and need for behavioral treatments.

Positive airway pressure adherence among patients with obstructive sleep apnea and cognitive impairment: A narrative review.

Adults with Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD) have increased rates of Obstructive Sleep Apnea (OSA). Positive Airway Pressure (PAP) is the first-line treatment for OSA and may have potential benefits for slowing cognitive decline in these individuals. However, adherence is low in PAP users overall and those with cognitive impairment may have unique challenges. Furthermore, there has been little systematic study of the use of PAP or strategies to enhance PAP adherence among those with AD or MCI. The aim of this review is to examine existing observational, quasi-experimental and experimental studies of the effects of PAP on cognitive function. In addition, our goal was to gather evidence about the adherence rates, and support for PAP among adults with MCI and mild to moderate AD. Through searches of electronic databases (University of Utah Library, SAGE Publishing, PubMed, Wiley, EBSCO, Science Direct, ProQuest, and NCBI), we identified 11 articles that fit our study inclusion criteria. Synthesis of data was performed with a focus on cognitive outcomes of PAP interventions and adherence. Findings from the studies showed that multiple indices of memory improved with PAP use. Adherence in MCI and AD populations was largely comparable to adherence reported in general adult populations, but more research is needed to optimize systems for providing support for PAP users and caregivers. Results support PAP as a promising intervention in this population but more research is needed to make definitive conclusions about the relationship between PAP use and improved cognitive function. Furthermore, research is needed to determine if additional interventions are needed to support patients and caregivers.

A feasibility study to understand the components of behavioral sleep extension.

Objectives: The goal of this study was to examine the contribution of sleep extension intervention components (wearable sleep tracker and coaching) on sleep extension outcomes. Patient involvement: This study collected open ended qualitative responses of treatment preference, acceptability, and feasibility as a key outcome. Methods: Adults aged 25 to 65 years with sleep duration <7 h and BMI ≥ 25 were randomized into one of four groups: Self-Management (control), Fitbit, Telephone Coaching, or Fitbit + Coaching. Self-report questionnaires and actigraphy were completed at baseline, post-intervention (6 weeks), and 12-weeks. Analyses used mixed models. Results: Among the 38 adults randomized, the Fitbit + Coaching group had larger but non-significant improvements in sleep duration compared with the self-management group. The coaching group demonstrated significant improvements in sleep-related impairment. All groups demonstrated feasibility and acceptability but the Fitbit + Coaching group reported themes of accountability. Conclusions: Results suggest that sleep extension interventions are feasible and acceptable but components affect the pattern of sleep and other outcomes. Practical implications: Sleep extension is feasible and acceptable; the combination of coaching and the wearable device may lead to larger changes in sleep due to enhanced accountability.

What a difference a year makes: Objective rest/activity patterns, circadian phase markers, and sleep quality before and during the COVID-19 pandemic.

OBJECTIVES: The COVID-19 pandemic led to numerous changes in sleep duration, quality, and timing. The goal of this study was to examine objective and self-reported changes in sleep and circadian timing before and during the pandemic. METHODS: Data were utilized from an ongoing longitudinal study of sleep and circadian timing with assessments at baseline and 1-year follow-up. Participants had baseline assessment between 2019 and March 2020 (before pandemic) and 12-month follow-up between September 2020 and March 2021 (during pandemic). Participants completed 7 days of wrist actigraphy, self-report questionnaires, and laboratory-collected circadian phase assessment (dim light melatonin onset). RESULTS: Actigraphy and questionnaire data were available for 18 participants (11 women and 7 men, Mean = 38.8 years, SD = 11.8). Dim light melatonin onset was available for 11 participants. Participants demonstrated statistically significant decreases in sleep efficiency (Mean = -4.11%, SD = 3.22, P = .001), worse scores on Patient-Reported Outcome Measurement Information System sleep disturbance scale (Mean increase = 4.48, SD = 6.87, P = .017), and sleep end time delay (Mean = 22.4 mins, SD = 44.4 mins, P = .046). Chronotype was significantly correlated with change in dim light melatonin onset (r = 0.649, P = .031). This suggests that a later chronotype is associated with a greater delay in dim light melatonin onset. There were also non-significant increases in total sleep time (Mean = 12.4 mins, SD = 44.4 mins, P = .255), later dim light melatonin onset (Mean = 25.2 mins, SD = 1.15 hrs, P = .295), and earlier sleep start time (Mean = 11.4 mins, SD = 48 mins, P = .322). CONCLUSION: Our data demonstrate objective and self-reported changes to sleep during the COVID-19 pandemic. Future studies should look at whether some individuals will require intervention to phase advance sleep when returning to previous routines such as returning to office and school settings.

Behavioral and psychological treatments for NREM parasomnias: A systematic review.

BACKGROUND: Non-rapid eye movement (NREM) parasomnias are often benign and transient, requiring no formal treatment. However, parasomnias can also be chronic, disrupt sleep quality, and pose a significant risk of harm to the patient or others. Numerous behavioral strategies have been described for the management of NREM parasomnias, but there have been no published comprehensive reviews. This systematic review was conducted to summarize the range of behavioral and psychological interventions and their efficacy. METHODS: We conducted a systematic search of the literature to identify all reports of behavioral and psychological treatments for NREM parasomnias (confusional arousals, sexsomnia, sleepwalking, sleep terrors, sleep-related eating disorder, parasomnia overlap disorder). This review was conducted in line with PRISMA guidelines. The protocol was registered with PROSPERO (CRD42021230360). The search was conducted in the following databases (initially on March 10, 2021 and updated February 24, 2023): Ovid (MEDLINE), Cochrane Library databases (Wiley), CINAHL (EBSCO), PsycINFO (EBSCO), and Web of Science (Clarivate). Given a lack of standardized quantitative outcome measures, a narrative synthesis approach was used. Risk of bias assessment used tools from Joanna Briggs Institute. RESULTS: A total of 72 publications in four languages were included, most of which were case reports (68%) or case series (21%). Children were included in 32 publications and adults in 44. The most common treatment was hypnosis (33 publications) followed by various types of psychotherapy (31), sleep hygiene (19), education/reassurance (15), relaxation (10), scheduled awakenings (9), sleep extension/scheduled naps (9), and mindfulness (5). Study designs and inconsistent outcome measures limited the evidence for specific treatments, but some evidence supports multicomponent CBT, sleep hygiene, scheduled awakenings, and hypnosis. CONCLUSIONS: This review highlights the wide breadth of behavioral and psychological interventions for managing NREM parasomnias. Evidence for the efficacy of these treatments is limited by the retrospective and uncontrolled nature of most research as well as the infrequent use of validated quantitative outcome measures. Behavioral and psychological treatments have been studied alone and in various combinations, and recent publications suggest a trend toward preference for multicomponent cognitive behavioral therapies designed to specifically target priming and precipitating factors of NREM parasomnias.

Effects of Sleep-Extend on glucose metabolism in women with a history of gestational diabetes: a pilot randomized trial.

OBJECTIVES: Women with a history of gestational diabetes (GDM) are at 7-fold increase in the risk of developing diabetes. Insufficient sleep has also been shown to increase diabetes risk. This study aimed to explore the feasibility of a sleep extension in women with a history of GDM and short sleep, and effects on glucose metabolism. METHODS: Women age 18-45 years with a history of GDM and actigraphy confirmed short sleep duration (<7 h/night) on weekdays were randomized at a ratio of 1 control (heathy living information) to 2 cases (6 weeks of "Sleep-Extend" intervention: use of a Fitbit, weekly digital content, and weekly coaching to increase sleep duration). An oral glucose tolerance test (OGTT), 7-day actigraphy recording, and questionnaires were obtained at baseline and 6 weeks. Mean differences between baseline and end-of-intervention parameters were compared using independent samples t-tests. RESULTS: Mean (SD) sleep duration increased within the Sleep-Extend group (n=9, +26.9 (42.5) min) but decreased within the controls (n=5, - 9.1 (20.4) min), a mean difference (MD) of 35.9 min (95% confidence interval (CI) - 8.6, 80.5). Fasting glucose increased, but less in Sleep-Extend vs. control groups (1.6 (9.4) vs 10.4 (8.2) mg/dL, MD - 8.8 mg/dL (95% CI - 19.8, 2.1), while 2-h glucose levels after an OGTT did not differ. Compared to controls, Sleep-Extend had decreased fatigue score (MD - 10.6, 95%CI - 20.7, - 0.6), and increased self-report physical activity (MD 5036 MET- minutes/week, 95%CI 343, 9729. Fitbit compliance and satisfaction in Sleep-Extend group was high. CONCLUSION: Sleep extension is feasible in women with a history of GDM, with benefits in fatigue and physical activity, and possibly glucose metabolism. These data support a larger study exploring benefits of sleep extension on glucose metabolism in these high-risk women. TRIAL REGISTRATION: ClinicalTrials.gov , NCT03638102 (8/20/2018).

Couples-based interventions to promote PAP adherence among older adults: a qualitative study of patients, partners, and providers.

STUDY OBJECTIVES: Bed partners play a critical role in the treatment of obstructive sleep apnea and are affected by the treatment (or lack thereof) of their partner's obstructive sleep apnea, but few studies have included partners formally in treatment. In this qualitative study, we examine key stakeholder perspectives (patient, bedpartner, and sleep medicine provider) to inform the development of a novel, couples-based intervention to promote adherence to positive airway pressure (PAP) and sleep health among older adult couples. METHODS: We conducted 3 focus group discussions with patients with obstructive sleep apnea/using PAP and their partners and 3 focus group discussions with sleep medicine providers. A standard interview guide was used to gather stakeholder input: (1) to understand interdependence of sleep among couples with sleep apnea; (2) to understand collaborative strategies that couples are currently using to address their sleep health challenges, including their perceptions of what is helpful vs not helpful; and (3) feasibility of the intervention design and delivery. Interviews were transcribed and thematically analyzed. RESULTS: Participants (n = 25) included 9 patients, 7 partners, and 9 providers. Analysis of the discussion identified themes within the 3 topics addressed in the focus group discussions: (1) interdependence of sleep health among couples, (2) collaboration and other dyadic strategies for increasing PAP use, and (3) facilitators and barriers to a couples-based PAP adherence intervention. Results of the focus group discussions provided new insights into collaborative strategies that could be used to enhance the sleep health of both patients and partners. Patient/partners reported that a couples-based treatment could reduce common frustrations experienced by new PAP users, thereby benefiting their relationship. However, barriers to couples-based treatment included patients and partners feeling overwhelmed and reluctance to discuss intimacy. Providers recognized the benefits of involving partners but reported concern about exacerbating conflict in the couple. CONCLUSIONS: Results indicate that couples and providers are enthusiastic about couples-based treatment that addresses their individual and dyadic sleep health challenges and identified important barriers that will need to be addressed to enhance uptake by clinicians and participation/retention of couples. CITATION: Baron KG, Troxel WM, Galway S, et al. Couples-based interventions to promote PAP adherence among older adults: a qualitative study of patients, partners, and providers. J Clin Sleep Med. 2022;18(11):2627-2634.

EEG measures index neural and cognitive recovery from sleep deprivation.

Sleep deprivation impairs many cognitive abilities, but these impairments can be reversed after a certain quantity and quality of sleep. The ability to inhibit responding is particularly susceptible to disruption after prolonged wakefulness. How recovery sleep (RS) alters brain activity, leading to improved performance on a variety of cognitive tasks, remains unclear. This issue was examined in the current study using spectral analysis of electroencephalogram (EEG) data during sleep. These measures of sleep physiology were acquired after both normal sleep (NS) and RS, and were related to measures of inhibitory control and concurrent brain activity. Subjects were nine young adults who underwent functional magnetic resonance imaging twice, after 9 h of NS and after 10 h of RS that followed 38 h of being awake. A multiple regression model was used to examine differences between conditions in (1) EEG spectral power during sleep, (2) probability of successful inhibition in a go/no-go task, and (3) activation within a region of right prefrontal cortex during the task. Performance recovery, as indexed by reduced performance differences between conditions, was predicted by increased delta power and decreased sigma power in RS compared with NS. These EEG variables predicted most of the variance in inhibitory performance difference between conditions. Regressions also suggested that RS improved performance because of changes in brain function including prefrontal regions that resulted from delta rebound. We thus propose that slow waves, reflected in delta power during RS, act to restore brain function, thereby improving cognitive performance that entails response inhibition.

Integrative behavioral treatment for NREM parasomnias: a case series.

NONE: A variety of behavioral interventions have been shown to improve symptoms of non-rapid eye movement parasomnias. Prior reports have typically examined outcomes of a single behavioral intervention. However, non-rapid eye movement parasomnias may benefit from a multipronged treatment approach similar to that used in the behavioral treatment of other sleep disorders. Through a series of 3 case reports, we demonstrate the utility of a case-conceptualization based, integrative approach to behavioral treatment of adult non-rapid eye movement parasomnias. For all patients (2 with disorders of arousal and 1 with sleep-related eating disorder), symptoms were satisfactorily reduced after 3-6 sessions. Treatment was tailored to each individual, but common elements included education, hypnosis, and identifying and reducing priming factors (eg, stress, insufficient sleep) and precipitating factors (eg, noise or touch from bed partners).

Challenges and Opportunities for Applying Wearable Technology to Sleep.

Wearable technology has a history in sleep research dating back to the 1970s. Because modern wearable technology is relatively cheap and widely used by the general population, this represents an opportunity to leverage wearable devices to advance sleep medicine and research. However, there is a lack of published validation studies designed to quantify device performance against accepted gold standards, especially across different populations. Recommendations for conducting performance assessments and using wearable devices are now published with the goal of standardizing wearable device implementation and advancing the field.

Meal timing relative to DLMO: Associations with BMI and body fat.

BACKGROUND: Timing of eating relative to the dim light melatonin onset (DLMO) may serve as a modifiable risk factor for adverse cardiometabolic outcomes. The primary aim of this study was to examine whether the timing of eating relative to DLMO is associated with body mass index (BMI), body fat, and diet in healthy adults without the confound of sleep deprivation. METHODS: Healthy men and women (N = 97), ages 18-50, with a habitual sleep duration of ≥6.5 hours and ≤8.5 hours completed 7 days of actigraphy and daily sleep and food diaries. Participants underwent a dual-energy X-ray absorptiometry scan and blood draws to assess DLMO in the clinical research unit. RESULTS: A shorter duration between DLMO and the average clock time of the last meal (last meal-DLMO) was related to a higher number of meals consumed, b = 0.25, SEb = 0.06, P< .001, longer feeding duration, b = 0.84, SEb = 0.06, P< .001, greater carbohydrate intake, b = 9.08, SEb = 3.55, P= .01, and greater sugar intake, b = 4.73, SEb = 1.83, P= .01. Last meal-DLMO was not associated with BMI in the full sample; however, among those with later DLMO (after 10:30 PM) last meal-DLMO was related to higher BMI, b = 0.92, SEb = 0.36, P= .02. CONCLUSION: These results suggest that timing of last meal relative to DLMO may serve as a marker of circadian misalignment and that eating the last meal closer to DLMO may negatively impact dietary habits.

The association between time-of-day of habitual exercise training and changes in relevant cancer health outcomes among cancer survivors.

OBJECTIVE: To assess the relationship between time-of-day of exercise training and changes in relevant cancer health outcomes among cancer survivors. METHODS: Retrospective analysis of data collected from 2016-2019 from a hospital-based exercise oncology program. Descriptive statistics were calculated for demographic, clinical, and exercise timing characteristics (e.g. AM, PM, or mix) among survivors with available data for exercise training time (n = 233). For the total sample and a breast cancer sub-analysis, univariate analysis of covariance, adjusted for age, was carried out by exercise training time, for change in the following outcomes collected during the program's assessment sessions: cardiorespiratory fitness and muscular endurance (human performance variables), physical function, anthropometrics, self-reported fatigue, and quality of life (QoL). Change in body mass index (BMI) and body weight was included in the breast cancer analysis. RESULTS: Overall, 37.3% of survivors habitually engaged in AM exercise (e.g. ≥ 75% AM training), 34.3% in PM exercise, and 28.3% in a mix of AM and PM exercise training throughout the program. Median time in the program was 17 weeks. Significant improvements in most human performance and physical function variables were observed in the total sample regardless of exercise training time-of-day. Among breast cancer survivors, PM but not AM or mixed was associated with improvements in fitness, and lower-body muscular endurance and function. Mixed exercise timing was linked with greater increase in waist circumference (total sample: 3.02cm, 95%CI 1.55, 4.49; breast cancer: 3.57cm 95%CI 0.96, 6.18), body weight (breast cancer: 1.6kg, 95%CI 0.3, 2.8) and BMI (breast cancer: 0.6kg/m2, 95%CI 0.1, 1.0). AM and PM exercise, but not mixed, was associated with improvements in fatigue and QoL. CONCLUSION: Time-of-day of exercise training may differentially impact changes in human performance and physical function variables. Mixed exercise training time may result in less favorable outcomes related of weight management variables among cancer survivors.

Perceived barriers to psychological treatments and their relationship to depression.

In spite of repeated calls for research and interventions to overcome individual and systemic barriers to psychological treatments, little is known about the nature of these barriers. To develop a measure of perceived barriers to psychological treatment (PBPT), items derived from 260 participants were administered to 658 primary care patients. Exploratory factor analysis on half the sample resulted in 8 factors, which were supported by confirmatory factor analysis conducted on the other half. Associations generally supported the criterion validity of PBPT scales, with self-reported concurrent use of psychotherapy and psychotherapy attendance in the year after PBPT administration. Depression was associated with greater endorsement of barriers. These findings suggest that the PBPT may be useful in assessing perceived barriers.

Do Physical Activity, Caloric Intake, and Sleep Vary Together Day to Day? Exploration of Intraindividual Variability in 3 Key Health Behaviors.

BACKGROUND: Little is known about how daily fluctuations in health behaviors relate to chronic disease risk. The goal of this study was to examine whether variability in physical activity, caloric intake, and sleep is related to body composition (body mass index and body fat percentage). METHODS: Healthy adults (N = 103; 64% female) were monitored for 7 days to assess physical activity (SenseWear Armband), caloric intake (daily food diaries), and sleep duration and timing (Actiwatch Spectrum). Data were analyzed using correlations (between- and within-subjects correlations) and regression. RESULTS: The results demonstrated that variabilities in physical activity, caloric intake, and sleep were unrelated. Caloric intake and sleep variability were unrelated to body composition. At greater levels of physical activity variability, any level of physical activity was protective for body composition. CONCLUSIONS: These results suggest that among healthy adults, variabilities in health behaviors may be independent of each other, and physical activity variability may be more strongly related to body composition among those who are less active.

Meal timing influences daily caloric intake in healthy adults.

The role that meal pattern plays in weight regulation is a popular topic of scientific and common debate. The goal of this study was to evaluate the relationship between meal timing with caloric intake and body mass index (BMI). We hypothesized that late meal timing and eating closer to sleep onset time would be associated with greater energy intake and higher BMI. Participants included 59 individuals recruited from the community. Rest/activity patterns were assessed using 7 days of wrist actigraphy, and caloric intake was evaluated using 7 days of diet logs. Results demonstrated that the timing of meals was associated with overall energy intake but not with BMI. In multivariate analyses controlling for age, sex, sleep duration, and timing, eating more frequently, later timing of the last meal, and a shorter duration between last meal and sleep onset predicted higher total caloric intake. In a mediational model, eating frequency explained the relationship between eating closer to sleep onset and total caloric intake. Results suggest that later relative timing of meals, particularly eating close to sleep, could lead to weight gain due to a greater number of eating occasions and higher total daily caloric intake. These findings have important implications for the development of novel, time-based interventions for weight management.

Timing and intensity of light correlate with body weight in adults.

Light exposure can influence sleep and circadian timing, both of which have been shown to influence weight regulation. The goal of this study was to evaluate the relationship between ambient light, sleep and body mass index. Participants included 54 individuals (26 males, mean age 30.6, SD = 11.7 years). Light levels, sleep midpoint and duration were measured with wrist actigraphy (Actiwatch-L) for 7 days. BMI was derived from self-reported height and weight. Caloric intake was determined from 7 days of food logs. For each participant, light and activity data were output in 2 minute epochs, smoothed using a 5 point (10 minute) moving average and then aggregated over 24 hours. The mean light timing above 500 lux (MLiT500) was defined as the average clock time of all aggregated data points above 500 lux. MLiT500 was positively correlated with BMI (r = 0.51, p<0.001), and midpoint of sleep (r = 0.47, p<0.01). In a multivariable linear regression model including MLiT500 and midpoint of sleep, MLiT500 was a significant predictor of BMI (B = 1.26 SE = 0.34, ß = 0.53 p = 0.001, r2Δ = 0.22). Adjusting for covariates, MLiT500 remained an independent predictor of BMI (B = 1.28 SE = 0.36, ß = 0.54, p = 0.002, r2Δ = 0.20). The full model accounted for 34.7% of the variance in BMI (p = 0.01). Exposure to moderate levels of light at biologically appropriate times can influence weight, independent of sleep timing and duration.