Trends in Daily Heart Rate Variability Fluctuations Are Associated with Longitudinal Changes in Stress and Somatisation in Police Officers

The emergence of wearable sensors that allow for unobtrusive monitoring of physiological and behavioural patterns introduces new opportunities to study the impact of stress in a real-world context. This study explores to what extent within-subject trends in daily Heart Rate Variability (HRV) and daily HRV fluctuations are associated with longitudinal changes in stress, depression, anxiety, and somatisation. Nine Dutch police officers collected daily nocturnal HRV data using an Oura ring during 15–55 weeks. Participants filled in the Four-Dimensional Symptoms Questionnaire every 5 weeks. A sample of 47 five-week observations was collected and analysed using multiple regression. After controlling for trends in total sleep time, moderate-to-vigorous physical activity and alcohol use, an increasing trend in the seven-day rolling standard deviation of the HRV (HRVsd) was associated with increases in stress and somatisation over 5 weeks. Furthermore, an increasing HRV trend buffered against the association between HRVsd trend and somatisation change, undoing this association when it was combined with increasing HRV. Depression and anxiety could not be related to trends in HRV or HRVsd, which was related to observed floor effects. These results show that monitoring trends in daily HRV via wearables holds promise for automated stress monitoring and providing personalised feedback.

Mortality associated with nonrestorative short sleep or nonrestorative long time-in-bed in middle-aged and older adults

Associations of sleep duration with human health could differ depending on whether sleep is restorative. Using data from 5804 participants of the Sleep Heart Health Study, we examined the longitudinal association of sleep restfulness combined with polysomnography-measured total sleep time (TST) or time in bed (TIB), representing different sleeping behaviors, with all-cause mortality. Among middle-aged adults, compared with restful intermediate TST quartile, the lowest TST quartile with feeling unrested was associated with higher mortality (hazard ratio [HR], 1.54; 95% confidence interval [CI] 1.01–2.33); the highest TST quartile with feeling rested was associated with lower mortality (HR, 0.55; 95% CI 0.32–0.97). Among older adults, the highest TIB quartile with feeling unrested was associated with higher mortality, compared with restful intermediate TIB quartile (HR, 1.57; 95% CI 1.23–2.01). Results suggest a role of restorative sleep in differentiating the effects of sleep duration on health outcomes in midlife and beyond.

Characteristics of Obstructive Sleep Apnea Patients With Hypertension and Factors Associated With Autotitration Acceptance

In order to explore the characteristics and treatment status of obstructive sleep apnea (OSA) patients with hypertension, a retrospective study was conducted on 306 patients admitted from October 2018 to December 2019. According to the apnea hypopnea index (AHI), OSA patients with hypertension were divided into three groups. 69 cases were mild OSA (5 ≤ AHI < 15), 86 cases were moderate (15 ≤ AHI < 30), and 151 cases were severe (AHI ≥ 30). Compared with patients in the mild and moderate groups, the severe group had more male patients, with higher body mass index (BMI) and non-rapid eye movement stage 1 accounted for total sleep time (N1%), and lower non-rapid eye movement stage 2 accounted for total sleep time (N2%), average and minimum blood oxygen. Among all the patients, those who underwent the titration test accounted for 20.6% (63/306). Multivariate analysis showed that sleep efficiency (p < 0.001) and AHI (p < 0.001) were independent factors for patients to accept titration test. OSA patients with hypertension had a low acceptance of titration therapy. These people with higher sleep efficiency and AHI were more likely to receive autotitration.

Sleep-Wake Pattern, Sleep Quality and Daytime Status in Fixed Day-Shift Hospital Workers

Objectives: Sleep issues are more prevalent in healthcare workers compared to workers in other industries. This study investigated sleep-wake pattern, sleep quality, and daytime status in hospital workers using a Galaxy Watch3 (GW3), a wrist-worn device that uses an accelerometer and heart rate sensor to distinguish sleep and wakefulness.Methods: Multiple sleep parameters including total sleep time (TST) were obtained using a GW3. The Epworth sleepiness scale (ESS), insomnia severity index (ISI), Pittsburgh sleep quality index (PSQI), and bedtime procrastination scale (BPS) were used to assess participants’ status.Results: A total of 70 daytime hospital workers (male, 45.7%; mean age, 35.66±7.79 yr) participated in the monitoring of their sleep-wake patterns for 30 consecutive days. Participants had a mean ESS of 8.14±3.62, ISI of 6.13±3.83, and PSQI of 4.86±2.14. The mean TST was 5.75±0.74 hr (range: 3.42–6.88) during workdays and 5.92±0.92 hr (range: 2.87–8.25) during free days. Chronotype (mid-sleep on freedays corrected for sleep debt accumulated over the work week) was 3.60±1.03 clock hr (range: 1.84–6.69). BPS was negatively correlated with age (rho=-0.27, p=0.022), TST of workdays (rho=-0.53, p<0.001), and TST of free days (rho=-0.43, p<0.001). A higher BPS was associated with larger social jetlag (rho=0.28, p=0.018) and later chronotype (rho=0.41, p<0.001).Conclusions: In this study, 91.5% of daytime hospital workers suffered from chronic sleep insufficiency (<7 hr during both workdays and free days) although their daytime sleepiness or subjective sleep were not poor. Individuals with a later chronotype had poorer sleep quality and worse sleep procrastination behavior.

Extreme sleep fragmentation for 11 consecutive days and nights does not significantly alter total sleep time, and sleep stage distribution, during the continuous alpine downhill skiing world record

Introduction: Extreme levels of sleep deprivation, fragmentation and management, are major problems in many sportive disciplines, ultramarathons, polar or extreme altitude expeditions, and in space operations. Material and methods: Polysomnographic (PSG) data was continuously recorded (total sleep time and sleep stage distribution) in a 34-year-old male whilst performing the new world record in long-term downhill skiing. He napped only during the short ski lift rides for 11 days and nights. Results: After an initial period of complete sleep deprivation for 24 hours, total sleep time and the total times of non-REM and REM achieved during the lift rides returned to standard values on the second day. PSG data revealed an average sleep time per 24 hours of 6 hours and 6 minutes. During daylight sleep was rarely registered. The subject experienced only two minor falls without injury and immediately resumed skiing. Conclusion: In a healthy, trained, elite male athlete, sleep fragmentation over 11 consecutive days did not significantly impair the sleep, motor or cognitive skills required to perform a continuous downhill skiing world record after an initial adaptation phase.

Expert Demand for Consumer Sleep Technology Features and Wearable Devices

Global demand for sleep-tracking wearables, or consumer sleep technologies (CSTs), is steadily increasing. CST marketing campaigns often feature a scientific component, but the scientific relevancy and monetary value of CST features within the sleep research community remains unquantified. Sleep medicine experts were recruited through social media and nonprobability sampling techniques to complete a survey identifying sleep metrics and device features that are most desirable to the scientific community. A hypothetical purchase task (HPT) estimated economic valuation for devices with different features by price. Forty-six (N=46) respondents with an average of 10&plusmn;6 years&rsquo; experience conducting research in real-world settings completed the online survey. Total sleep time was ranked as the most important measure of sleep followed by objective sleep quality while sleep architecture/depth and diagnostic information were ranked as least important. Experts preferred wrist-worn devices that could reliably determine sleep episodes as short as 20 minutes. Economic value was greater for hypothetical devices with longer battery life. These data set a precedent to determine how scientific relevance of a product impacts the potential market value of a CST device. This is the first known attempt to establish consensus opinion or economic valuation for scientifically-desirable CST features and metrics using expert elicitation.

Association Between Bedtime at Night and Systolic Blood Pressure in Adults in NHANES

Objectives: This study aimed to explore the association between bedtime at night and systolic blood pressure (SBP) in adults.Methods: We conducted a cross-sectional study composed of 7,642 individuals from the National Health and Nutrition Examination Survey (NHANES). Bedtime was defined as the response to the question: “What time do you usually fall asleep on weekdays or workdays?” SBP was taken using the average of all measured values. Multiple linear regression analyses were done to explore the relationship between bedtime and SBP.Results: The bedtime was changed from categorical variable to continuous variable for data analysis, and a significantly negative association was identified between bedtime and SBP (β, −0.23 [95% CI, −0.43, −0.02]). With the delay of bedtime, the SBP showed a gradual decrease trend, and it was dropped to the lowest at 0:00. After 0:00, the SBP was gradually increased with the delay of sleep time. The stratified analyses showed that in the female group, with the delay of bedtime, the range of SBP was decreased more obviously at 0:00. In the 18–45 year group, bedtime had little effect on SBP. Among ≥45 years old group, this trend was still the same. In the black group, an obvious downward trend was found at 22:00.Conclusion: With the delay of bedtime, the SBP had shown a gradual decrease trend, and it was dropped to the lowest at 0:00. After 0:00, the SBP was gradually increased with the delay of sleep time. Bedtime and SBP showed a U-shaped relationship.

Adaptive Scheduling for Time-Triggered Network-on-Chip-Based Multi-Core Architecture Using Genetic Algorithm

Adaptation in time-triggered systems can be motivated by energy efficiency, fault recovery, and changing environmental conditions. Adaptation in time-triggered systems is achieved by preserving temporal predictability through metascheduling techniques. Nevertheless, utilising existing metascheduling schemes for time-triggered network-on-chip architectures poses design time computation and run-time storage challenges for adaptation using the resulting schedules. In this work, an algorithm for path reconvergence in a multi-schedule graph, enabled by a reconvergence horizon, is presented to manage the state-space explosion problem resulting from an increase in the number of scenarios required for adaptation. A meta-scheduler invokes a genetic algorithm to solve a new scheduling problem for each adaptation scenario, resulting in a multi-schedule graph. Finally, repeated nodes of the multi-schedule graph are merged, and further exploration of paths is terminated. The proposed algorithm is evaluated using various application model sizes and different horizon configurations. Results show up to 56% reduction of schedules necessary for adaptation to 10 context events, with the reconvergence horizon set to 50 time units. Furthermore, 10 jobs with 10 slack events and a horizon of 40 ticks result in a 23% average sleep time for energy savings. Furthermore, the results demonstrate the reduction in the state-space size while showing the trade-off between the size of the reconvergence horizon and the number of nodes of the multi-schedule graph.

Efficacy of Face-to-Face Delivered Cognitive Behavioral Therapy in Improving Health Status of Patients With Insomnia: A Meta-Analysis

Background: Face-to-face cognitive behavioral therapy (CBT) is one of the most widely used non-pharmacological treatment approaches for insomnia. The aim of this study is to assess the efficacy of face-to-face delivered CBT on health outcomes and to evaluate the effect of CBT components as subgroup variables to explain the efficacy of face-to-face delivered CBT on health outcomes in adults over 18 years old with insomnia.Methods: Relevant randomized controlled trial studies published in the past 22 years were searched through the electronic databases. The Physiotherapy Evidence Database (PEDro) scale was used to assess the quality of the 31 included studies. The mean difference and standard deviation of outcome variables and subgroup variables were analyzed using random effect model, and the heterogeneity among the articles was assessed with the Q-test and I2. Egger regression analysis was used to assess publication bias.Results: The meta-analysis showed a significant reduction in Insomnia Severity Index [standardized mean difference (SMD) = −2.56, 95% CI −3.81 to −1.30, p &lt; 0.001], Pittsburgh Sleep Quality Index (SMD = −0.96, 95% CI −1.25 to −0.68, p &lt; 0.001), sleep onset latency (SMD = −1.31, 95% CI −2.00 to −0.63, p &lt; 0.001), wakening after sleep onset (SMD = −1.44, 95% CI −2.14 to −0.74, p &lt; 0.001), number of awakenings (SMD = −1.18, 95% CI −2.10 to −0.26, p &lt; 0.05), depression (SMD = −1.14, 95% CI −1.85 to −0.42, p &lt; 0.01), and fatigue (SMD = −2.23, 95% CI −3.87 to −0.58, p &lt; 0.01), and a significant increase in total sleep time (SMD = 0.63, 95% CI 0.28 to 0.98, p &lt; 0.001), sleep efficiency (SMD = 1.61, 95% CI 0.92 to 2.29, p &lt; 0.001), and physical health (SMD = 0.42, 95% CI 0.08 to 0.76, p &lt; 0.05), in the CBT intervention group compared with the control group. There was no significant change in anxiety (SMD = −0.62, 95% CI −1.55 to 0.32, p &gt; 0.05) and mental health (SMD = 1.09, 95% CI −0.59 to 2.77, p &gt; 0.05) in CBT intervention group compared with control group. Group-delivered studies with larger number of intervention sessions and longer duration of single session provided a larger improvement in sleep quality.Conclusion: Face-to-face delivered CBT is effective in increasing total sleep time, sleep efficiency, and physical health, and reducing Insomnia Severity Index scores, Pittsburgh Sleep Quality Index scores, sleep onset latency, wakening after sleep onset, number of awakenings, depression, anxiety, and fatigue in patients with insomnia. Face-to-face delivered CBT is more effective when delivered through a larger number of sessions with longer duration of each session, and when delivered in groups. Face-to-face CBT is recommended to provide treatment to patients with insomnia in clinical settings.Systematic Review Registration:www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020200091, identifier: CRD4202020009.