Sleep disturbance is associated with not only shorter sleep duration, but also longer time in bed: a Japanese general population survey

Timing is everything: Circadian rhythms and their role in the control of sleep

Sleep and the circadian clock are intertwined and have persisted throughout history. The suprachiasmatic nucleus (SCN) orchestrates sleep by controlling circadian (Process C) and homeostatic (Process S) activities. As a "hand" on the endogenous circadian clock, melatonin is critical for sleep regulation. Light serves as a cue for sleep/wake control by activating retino-recipient cells in the SCN and subsequently suppressing melatonin. Clock genes are the molecular timekeepers that keep the 24 h cycle in place. Two main sleep and behavioural disorder diagnostic manuals have now officially recognised the importance of these processes for human health and well-being. The body's ability to respond to daily demands with the least amount of effort is maximised by carefully timing and integrating all components of sleep and waking. In the brain, the organization of timing is essential for optimal brain physiology.

Association of insomnia symptoms and non-restorative sleep with Typus melancholicus: a Japanese general population survey

This study aimed to investigate the association between insomnia symptoms and non-restorative sleep (NRS) in individuals with Typus melancholicus, a personality trait linked to depression, in the general population. We analyzed data from a Japanese cross-sectional survey of 2519 randomly sampled adults. Typus melancholicus was evaluated using a modified version of Kasahara's Typus melancholicus inventory (modified-KTM). Logistic regression analysis was used to examine the associations of insomnia symptoms and NRS with modified-KTM scores. We demonstrated that insomnia symptoms and NRS were both positively associated with modified-KTM scores. Our results provide evidence for an association between Typus melancholicus and insomnia.

A Cross-Sectional Study of Evening Hyperphagia and Nocturnal Ingestion: Core Constituents of Night Eating Syndrome with Different Background Factors

This web-based cross-sectional survey aimed to elucidate the differences between the two core symptoms of night eating syndrome (NES): evening hyperphagia and nocturnal ingestion in the general Japanese population aged 16–79 years. Participants who consumed at least 25% of daily calories after dinner were defined as having evening hyperphagia. Those who consumed food after sleep initiation at least twice a week were determined to have nocturnal ingestion. Of the 8348 participants, 119 (1.5%) were categorized in the evening hyperphagia group, 208 (2.6%) in the nocturnal ingestion group, and 8024 in the non-NES group. Participants with evening hyperphagia and nocturnal ingestion had significantly higher anxiety scores (p < 0.05 and p < 0.001, respectively) and depression (p < 0.001 for both) than those without NES. Multiple logistic regression analysis revealed that evening hyperphagia was significantly and independently associated with higher body mass index, shorter sleep duration, later sleep-wake schedule, and higher insomnia score, while nocturnal ingestion was significantly and independently associated with younger age, smoking habit, living alone, earlier sleep-wake schedule, and higher insomnia score. Sleep duration and sleep-wake schedule characteristics in the two groups were opposite, suggesting differences in the sleep pathophysiology mechanisms.

Age and gender differences in objective sleep properties using large-scale body acceleration data in a Japanese population

Using large-scale objective sleep data derived from body acceleration signals of 68,604 Japanese residents ranging from adolescents to the elderly (10–89 years old), we found significant age- and gender-related differences in sleep properties (timing, duration, and quality) in real-life settings. Time-in-bed and total sleep time (TST) showed a U-shaped association with age, indicating their decrease in adulthood following their increase in the elderly. There was a remarkable shift in sleep phase toward earlier bedtime and earlier wake time with increasing age (> 20 years), together with worsening of sleep quality, which is estimated by sleep efficiency (SE) and wake time after sleep onset. Gender comparisons showed that TST was shorter in women than in similarly aged men, which is much evident after the age of 30 years. This was associated with later bedtimes and greater age-related deterioration of sleep quality in women. Compared to men in the same age group, women over age 50 demonstrated a greater reduction in SE with aging, due mainly to increasing durations of nighttime awakening. These differences can be attributed to several intricately intertwined causes, including biological aging as well as socio-cultural and socio-familial factors in Japan. In conclusion, our findings provide valuable insights on the characteristics of Japanese sleep habits.

Sleep disturbance in heart failure: A concept analysis

AIM

This concept analysis aims to analyze the concept of sleep disturbance (SD) in the context of heart failure (HF) to guide the development of a clearly defined definition.

BACKGROUND

The term "sleep disturbance" has been used in the literature to describe sleep problems and sleep disorders among individuals with HF. Environmental, physical, psychological, behavioral, and developmental factors complicate the phenomenon of SD in HF.

DESIGN

Walker and Avant's method was used for this concept analysis.

DATA SOURCE

Published literature from 2000 to 2020 was identified from electronic health profession-related databases. The current definition and usages of SD were abstracted from empirical work and electronic databases.

REVIEW METHODS

A focused review of abstracts and full text relating to SD in HF was performed. Studies featuring original data and peer-reviewed articles written in English were included to investigate the multifactorial contextual meaning of the concept.

RESULTS

SD in HF can be described as a condition in which individuals experience difficulty initiating and maintaining sleep, and difficulty continuing or resuming sleep due to frequent nocturnal arousals due to HF symptoms, sleep-disordered breathing, insomnia, and psychological burdens.

CONCLUSIONS

To evaluate SD in HF, clinicians must examine the underlying causes to provide the contextual meaning of the concept. A clearly defined and distinguishable concept of SD in HF provides a possibility for accurate measurements of sleep quality, exploring interventions, and evaluating outcomes.