Naturally Occurring Consecutive Sleep Loss and Day-to-Day Trajectories of Affective and Physical Well-Being

Cognitive impairment and depression precede increased HDL-C levels in middle-aged and older Chinese adults: cross-lagged panel analyses

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) is widely recognized for its protective effects against cognitive decline. However, recent studies have presented conflicting results, with some suggesting no significant cognitive benefits or even an increased risk of dementia associated with high HDL-C levels. For those who suffer from depression, the cognitive benefits of HDL-C may be diminished or reversed. The purpose of this study is to investigate the associations between HDL-C, cognitive ability, and depressive symptoms in middle-aged and older Chinese adults.

METHODS

The datasets utilized were sourced from the China Health and Retirement Longitudinal Study (CHARLS) for the years 2011 and 2015, comprising 4,302 participants. Cross-lagged models were employed to explore the temporal sequence between cognitive performance and HDL-C levels, and to examine the interplay among depression, cognition, and HDL-C. Confounding factors such as sociodemographic characteristics, sleep conditions, and history of chronic diseases were controlled for.

RESULTS

The analysis revealed unidirectional effects of baseline impaired cognition and greater severity of depression on increased HDL-C levels at follow-up (β =  - 0.036 and β = 0.028, respectively, P < 0.05). However, higher baseline HDL-C levels did not significantly predict cognitive performance or depression 4 years later (β =  - 0.008 and β = 0.023, respectively, P > 0.05). Depressive symptoms and cognition were found to have a significant bidirectional association (β =  - 0.026 and β =  - 0.053, respectively, P < 0.05).

CONCLUSIONS

Cognitive impairment and depression are associated with higher HDL-C levels, whereas higher HDL-C levels do not appear to protect against cognitive decline or depressive symptoms. These findings underscore the importance of preserving cognitive and mental health, which may lower the likelihood of cardiovascular disease and dementia. Future studies should validate these findings and develop targeted interventions tailored to specific populations.

Association between factors in life course and physiological disorders among the middle-aged and older population in Zhoushan city of Zhejiang province

OBJECTIVES

To analyze the associations between factors in life course and physiological disorders in the middle-aged and elderly population of Zhoushan city of Zhejiang province, and the mediating roles of lifestyle and mental health.

METHODS

A total of 1553 island residents aged ≥45 years were enrolled from the Zhejiang Metabolic Syndrome Cohort Zhoushan Liuheng Sub-cohort. The demographic information, life-course information, lifestyle, and mental health information of participants were documented, and blood samples of were collected. The status of aging was evaluated by physiological disorders calculation model developed by authors previously. The Shapley value decomposition method was used to assess the cumulative and relative contribution of multiple factors in life course to the aging. Principal component analysis and hierarchical cluster analysis were used to classify subgroups. General linear regression model was used to assess the associations between the life-course subgroups and physiological disorders. Five key factors associated with aging were finally identified. Logistic regression model, general linear regression model, and mediation analysis model were used to assess the complex associations between life-course subgroups, key factors, unhealthy lifestyle, mental health, and aging.

RESULTS

Shapley value decomposition method indicated that eight types of life-course factors explained 6.63% (SE=0.0008) of the individual physiological disorders variance, with the greatest relative contribution (2.78%) from adversity experiences in adulthood. The study participants were clustered into 4 subgroups, and subgroups experiencing more adversity in adulthood and having low educational attainment or experiencing more trauma and having poorer relationships in childhood had significantly higher levels of physiological disorders. Life-course subgroups and key factors (childhood trauma and health, adversity experience in adulthood, and lower education) were positively associated with unhealthy lifestyles (β=0.12-0.41, P<0.05). In addition, life-course subgroups and key factors (adversity experience in adulthood) were positively associated with psychological problems (OR=2.14-4.68, P<0.05). Unhealthy lifestyle scores showed a marginal significant association with physiological disorders (β=0.03, P=0.055). However, no significant association was found between psychological problems and physiological disorders (β=0.03, P=0.748). The results of the mediation analysis model suggested that unhealthy lifestyles partially mediated the associations between life-course subgroups, adversity experience in adulthood and physiological disorders.

CONCLUSIONS

Multiple life-course factors contribute about 6% of the variance in physiological disorders in the middle aged and elderly population of the study area; subgroups with adverse life course experiences have higher levels of aging; and the association may be partially mediated by unhealthy lifestyles.

Subjective sleep may mediate the associations between tomorrow anticipations and next-day affect

This study investigated whether stress and positive anticipations about tomorrow are associated with emotional experiences the following day, mediated by the preceding night's sleep. Data were from 141 full-time nurses, utilizing a 14-day ecological momentary assessment combined with actigraphy sleep monitoring. Each evening, participants rated the anticipated pleasantness or stressfulness of the following day. Each morning, participants reported on their previous night's sleep. Additionally, participants reported their momentary positive affect (PA) and negative affect (NA) three times per day, with daily averages computed. Multilevel mediation models, adjusted for sociodemographics, work shift, workday, and previous day's affect, revealed that days following more stress anticipations were associated with reduced PA and increased NA. Conversely, days following more pleasantness anticipations were associated with increased PA and decreased NA. These within-person associations were mediated by self-reported time-in-bed, sufficiency, and quality, such that less stressful and more pleasant anticipations were associated with better sleep, and better sleep was subsequently associated with increased PA and decreased NA. No mediation was found by the actigraphy sleep parameters. Findings suggest that emotional states may covary not only with present stimuli but also with anticipation of future events and subjective sleep recovery in the context of those anticipations.

Monitoring Daily Sleep, Mood, and Affect Using Digital Technologies and Wearables: A Systematic Review

Background: Sleep and affective states are closely intertwined. Nevertheless, previous methods to evaluate sleep-affect associations have been limited by poor ecological validity, with a few studies examining temporal or dynamic interactions in naturalistic settings. Objectives: First, to update and integrate evidence from studies investigating the reciprocal relationship between daily sleep and affective phenomena (mood, affect, and emotions) through ambulatory and prospective monitoring. Second, to evaluate differential patterns based on age, affective disorder diagnosis (bipolar, depression, and anxiety), and shift work patterns on day-to-day sleep-emotion dyads. Third, to summarise the use of wearables, actigraphy, and digital tools in assessing longitudinal sleep-affect associations. Method: A comprehensive PRISMA-compliant systematic review was conducted through the EMBASE, Ovid MEDLINE(R), PsycINFO, and Scopus databases. Results: Of the 3024 records screened, 121 studies were included. Bidirectionality of sleep-affect associations was found (in general) across affective disorders (bipolar, depression, and anxiety), shift workers, and healthy participants representing a range of age groups. However, findings were influenced by the sleep indices and affective dimensions operationalised, sampling resolution, time of day effects, and diagnostic status. Conclusions: Sleep disturbances, especially poorer sleep quality and truncated sleep duration, were consistently found to influence positive and negative affective experiences. Sleep was more often a stronger predictor of subsequent daytime affect than vice versa. The strength and magnitude of sleep-affect associations were more robust for subjective (self-reported) sleep parameters compared to objective (actigraphic) sleep parameters.

Too little or too much: nonlinear relationship between sleep duration and daily affective well-being in depressed adults

BACKGROUND

In addition to having higher negative affect and lower positive affect overall, depressed individuals exhibit heightened affective reactivity to external stimuli than non-depressed individuals. Sleep may contribute to day-to-day fluctuations in depressed individuals, given that sleep disturbance is a common symptom of depression. Yet, little is known about changes in daily affect as a function of nightly sleep duration in depressed adults and non-depressed adults. The current study examined whether and how naturally-occurring sleep duration is associated with negative and positive affect, and how these associations differ between depressed vs. non-depressed adults.

METHODS

Data were drawn from the second wave of the National Study of Daily Experiences (NSDE), a daily diary project of the Midlife in the United States (MIDUS) study. The sample of 2,012 adults (Mage=56.5; 57% female; 84% white) completed eight-day diary interviews via telephone on their daily experiences including nightly sleep duration and negative and positive affect. They also completed assessments of the Composite International Diagnostic Interview-Short form, and depressed status was determined based on DSM-III. Multilevel regression models with linear, quadratic, and cubic terms of sleep duration examined the nonlinear relationship between nightly sleep duration and daily affect. Interaction terms with depression status were added to examine differences between depressed and non-depressed adults.

RESULTS

Depressed adults exhibited significant and greater fluctuations in daily affect as a function of nightly sleep duration than non-depressed adults. Specifically, the degree of decrease in positive affect and increase in negative affect was greater when depressed adults slept 2 or more hours less or longer than their usual sleep hours. Non-depressed adults exhibited relatively stable daily affect regardless of their nightly sleep hours.

CONCLUSIONS

Sleep duration is nonlinearly associated with affect in daily lives of depressed adults, highlighting that both having too little sleep and excessive sleep are associated with adverse daily affective well-being. Implementing sleep interventions to promote an appropriate sleep duration may help improve daily affect among depressed adults.

The effects of sustained mild sleep restriction on stress and distress among healthy adults: Findings from two randomized crossover studies

OBJECTIVE/BACKGROUND

Experimental studies suggest that sleep loss affects psychological outcomes. However, most studies focus on acute severe in-laboratory sleep restriction, with limited ecological validity. This study examines the impact of sustained mild sleep restriction (SR) on stress and distress among healthy adults in a naturalistic home environment.

PATIENTS/METHODS

We analyzed data from two randomized crossover studies. Individuals who regularly slept 7-9 h/night completed two 6-wk intervention phases separated by a 6-wk washout: habitual sleep (HS: maintenance of habitual bed and wake times) and SR (delayed bedtime by 1.5 h/night and maintenance of habitual wake time). Adherence to sleep duration requirements was verified with wrist actigraphy and daily sleep diaries during each intervention phase. Measures of perceived stress, subjective anxiety, subjective depression, rumination, and cortisol were collected at baseline and endpoint of each intervention phase.

RESULTS

Sixty-two participants (age 36.4 ± 14.0 y, 85.5 % women, 63.3 % racial/ethnic minority) were included in our analyses. Mean total sleep time was 7.4 ± 0.4 h/night during HS and 6.2 ± 0.4 h/night during SR (p < 0.001). Higher perceived stress (3.6 ± 1.0, p = 0.0007) and subjective anxiety (1.1 ± 0.5, p = 0.039) were observed after SR compared to HS. No effect of sleep condition was observed on subjective depression, rumination, and cortisol.

CONCLUSIONS

Our findings suggest that prolonged mildly insufficient sleep, similar to what commonly experienced in the real world, can lead to increased perceived stress and subjective anxiety in healthy adults. Addressing sleep loss, even if mild, should be a key component of interventions aimed at promoting mental health in the general population.

Assessing 'readiness' by tracking fluctuations in daily sleep duration and their effects on daily mood, motivation, and sleepiness

STUDY OBJECTIVES

Consumer sleep trackers issue daily guidance on 'readiness' without clear empirical basis. We investigated how self-rated mood, motivation, and sleepiness (MMS) levels are affected by daily fluctuations in sleep duration, timing, and efficiency and overall sleep regularity. We also determined how temporally specific these associations are.

METHODS

119 healthy university students (64 female, mean age = 22.54 ± 1.74 years) wore a wearable sleep tracker and undertook twice-daily smartphone-delivered ecological momentary assessment of mood, motivation, and sleepiness at post-wake and pre-bedtime timings for 2-6 weeks. Naps and their duration were reported daily. Nocturnal sleep on 2471 nights were examined using multilevel models to uncover within-subject and between-subject associations between sleep duration, timing, efficiency, and nap duration on following day MMS ratings. Time-lagged analyses examined the temporal specificity of these associations. Linear regression models investigated associations between MMS ratings and sleep variability, controlling for sleep duration.

RESULTS

Nocturnal sleep durations were short (6.03 ± 0.71 h), and bedtimes were late (1:42AM ± 1:05). Within-subjects, nocturnal sleep longer than a person's average was associated with better mood, higher motivation, and lower sleepiness after waking. Effects of such longer sleep duration lingered for mood and sleepiness till the pre-bedtime window (all Ps < .005) but did not extend to the next day. Between-subjects, higher intraindividual sleep variability, but not sleep duration, was associated with poorer mood and lower motivation after waking. Longer average sleep duration was associated with less sleepiness after waking and lower motivation pre-bedtime (all Ps < .05). Longer naps reduced post-nap sleepiness and improved mood. Controlling for nocturnal sleep duration, longer naps also associated with lower post-waking sleepiness on the following day.

CONCLUSIONS

Positive connections between nocturnal sleep and nap duration with MMS are temporally circumscribed, lending credence to the construction of sleep-based, daily 'readiness' scores. Higher sleep duration variability lowers an individual's post waking mood and motivation.

CLINICAL TRIAL ID

ClinicalTrials.gov NCT04880629.

The effect of short daytime napping on cognitive function, sleep quality, and quality of life in mild cognitive impairment patients

Mild cognitive impairment (MCI) is a neurological disorder that can increase the risk of Alzheimer's disease (AD) by three to five times more than those with normal cognition. To better understand the effects of daytime napping on MCI patients, a study was conducted to measure the effects of short naps on cognitive function, sleep quality, and quality of life. In total, 38 participants were asked to take 20-minute naps between 1:00p.m. and 3:00p.m. three times a week for eight weeks. The cognitive function of the participants was measured using the Thai version of the Montreal Cognitive Assessment (Thai-MoCA), their sleep quality was measured using the Thai version of the Pittsburgh Sleep Quality Index (Thai-PSQI), and their quality of life was measured using the Thai version of the Quality of Life (Thai-QoL) questionnaire. After the 8-week period, the participants' scores for the Thai-MoCA and the Thai-QoL questionnaire showed a significant improvement (p < 0.001 for both), while the Thai-PSQI decreased significantly (p = 0.012). This suggests that taking short daytime naps can help to improve the cognitive function, sleep quality, and quality of life of MCI patients.

Warning: medical education is hazardous to your mental health. Medical students should make an informed decision to begin and continue training

For decades there has been ample evidence that training to become a physician and practicing medicine is hazardous to one's health and wellness. In the face of the extremely high rates of suicide, substance abuse, depression and burnout in the medical student, resident, and physician populations, it would be dishonest to suggest medical education and practice is all gain and no pain. This article is directed to members of the medical education community and challenges stakeholders to view their teaching and training of medical students as an intervention requiring free and informed consent. We hope this exercise shifts the paradigm of educators and enables students to enter medical training from a free and informed position.

Effects of sleep deprivation on coronary heart disease

The presence of artificial light enables humans to be active 24 h a day. Many people across the globe live in a social culture that encourages staying up late to meet the demands of various activities, such as work and school. Sleep deprivation (SD) is a severe health problem in modern society. Meanwhile, as with cardiometabolic disease, there was an obvious tendency that coronary heart disease (CHD) to become a global epidemic chronic disease. Specifically, SD can significantly increase the morbidity and mortality of CHD. However, the underlying mechanisms responsible for the effects of SD on CHD are multilayered and complex. Inflammatory response, lipid metabolism, oxidative stress, and endothelial function all contribute to cardiovascular lesions. In this review, the effects of SD on CHD development are summarized, and SD-related pathogenesis of coronary artery lesions is discussed. In general, early assessment of SD played a vital role in preventing the harmful consequences of CHD.

Effects of High-Intensity Interval Training on Sleep: A Systematic Review and Meta-Analysis

Objectives: To use a quantitative approach to examine the effects of high-intensity interval training (HIIT) interventions on sleep for adults. Methods: PubMed, Ebsco, Web of Science, Cochrane Central Register of Controlled Trials, the China National Knowledge Infrastructure, and Wanfang Data were searched from their inception to December 2020. Intervention studies with a control group that examined the effects of HIIT interventions on sleep were included in this meta-analysis. The risk of bias was assessed using the tool provided by the Cochrane Handbook for Systematic Reviews of Interventions. Effect sizes (ESs), calculated as weighted mean difference (WMD) and standardized mean difference (SMD), were used to examine the effects of objective outcomes and subjective outcomes separately. Results: A large increase in sleep quality (SQ) reflected by the Pittsburgh Sleep Quality Index global scores [WMD = −0.90, 95%CI (−1.72, −0.07), p = 0.03, n = 8] and a small-to-medium favorable effect on sleep efficiency (SE) [SMD = 0.43, 95%CI (0.20, 0.65), p = 0.0002, n = 10] were found after HIIT intervention. In addition, sub-analyses results suggest that ESs were moderated by the type, duration and frequency, as well as the length of the HIIT intervention. Conclusions: HIIT may be a promising way to improve overall subjective SQ and objective SE. PROSPERO, protocol registration number: CRD42021241734.