Experimental sleep restriction causes endothelial dysfunction in healthy humans

Healthy Sleep Pattern, Metabolic Diseases, and Risk of Stroke: The Kailuan Cohort Study

Background

Sleep complaints were reported to be associated with stroke, however, the evidence on the association between healthy sleep pattern and stroke risk in Chinese is limited.

Objective

The aim of this study was to investigate the association between healthy sleep pattern and stroke in Chinese, and the influence of metabolic diseases on the association.

Methods

A total of 11,851 participants from the Kailuan study in China without stroke at baseline were included. We calculated a healthy sleep score according to four sleep factors, and defined the low-risk groups as follows: no insomnia, no excessive daytime sleepiness, no frequent snoring, and sleep 7-8h/d. Each low-risk sleep factor was assigned a score of 1. Cox proportional hazard models were used to assess the association between healthy sleep score and stroke. Mediation analysis was used to estimate the role of metabolic diseases (obesity, diabetes, and hypertension) in the healthy sleep score-stroke association.

Results

During a mean follow-up period of 7.7 years, 504 cases of stroke were identified. A higher healthy sleep score was associated with a lower risk of stroke in a dose-response manner (P-trend=0.03). The adjusted hazard ratio (HR) for participants with a healthy sleep score of 4 versus ≤2 was 0.75 (95% confidence interval [CI]: 0.56, 0.96). In addition, obesity, diabetes, and hypertension collectively explained 21.9% (95% CI: 17.2, 26.5) of the association between healthy sleep score and stroke.

Conclusion

Adherence to healthy sleep pattern was associated with a lower risk of stroke, and the favorable association was partially mediated by metabolic diseases.

The Role of Sleep in Cardiovascular Disease

PURPOSE OF REVIEW

Sleep is an important component of cardiovascular (CV) health. This review summarizes the complex relationship between sleep and CV disease (CVD). Additionally, we describe the data supporting the treatment of sleep disturbances in preventing and treating CVD.

RECENT FINDINGS

Recent guidelines recommend screening for obstructive sleep apnea in patients with atrial fibrillation. New data continues to demonstrate the importance of sleep quality and duration for CV health. There is a complex bidirectional relationship between sleep health and CVD. Sleep disturbances have systemic effects that contribute to the development of CVD, including hypertension, coronary artery disease, heart failure, and arrhythmias. Additionally, CVD contributes to the development of sleep disturbances. However, more data are needed to support the role of screening for and treatment of sleep disorders for the prevention of CVD.

Ckip-1 3'UTR alleviates prolonged sleep deprivation induced cardiac dysfunction by activating CaMKK2/AMPK/cTNI pathway

Sleep deprivation (SD) has emerged as a critical concern impacting human health, leading to significant damage to the cardiovascular system. However, the underlying mechanisms are still unclear, and the development of targeted drugs is lagging. Here, we used mice to explore the effects of prolonged SD on cardiac structure and function. Echocardiography analysis revealed that cardiac function was significantly decreased in mice after five weeks of SD. Real-time quantitative PCR (RT-q-PCR) and Masson staining analysis showed that cardiac remodeling marker gene Anp (atrial natriuretic peptide) and fibrosis were increased, Elisa assay of serum showed that the levels of creatine kinase (CK), creatine kinase-MB (CK-MB), ANP, brain natriuretic peptide (BNP) and cardiac troponin T (cTn-T) were increased after SD, suggesting that cardiac remodeling and injury occurred. Transcript sequencing analysis indicated that genes involved in the regulation of calcium signaling pathway, dilated cardiomyopathy, and cardiac muscle contraction were changed after SD. Accordingly, Western blotting analysis demonstrated that the cardiac-contraction associated CaMKK2/AMPK/cTNI pathway was inhibited. Since our preliminary research has confirmed the vital role of Casein Kinase-2 -Interacting Protein-1 (CKIP-1, also known as PLEKHO1) in cardiac remodeling regulation. Here, we found the levels of the 3' untranslated region of Ckip-1 (Ckip-1 3'UTR) decreased, while the coding sequence of Ckip-1 (Ckip-1 CDS) remained unchanged after SD. Significantly, adenovirus-mediated overexpression of Ckip-1 3'UTR alleviated SD-induced cardiac dysfunction and remodeling by activating CaMKK2/AMPK/cTNI pathway, which proposed the therapeutic potential of Ckip-1 3'UTR in treating SD-induced heart disease.

The Effect of Sleep Duration on Hypertension Risk in an Adult Asian Population: A Systematic Review and Meta-Analysis

Sleep duration has been proposed as a potential and important modifiable risk factor, yet its precise relationship with hypertension among Asian adults remains unclear. This meta-analysis aims to elucidate the impact of short sleep duration on hypertension risk within the adult Asian population. A systematic search of databases, including PubMed, Scopus, and ScienceDirect, was conducted to identify relevant studies published up to January 4, 2024. Eligible studies comprised observational cohort studies and cross-sectional studies that compared short sleep duration to normal sleep duration in relation to hypertension risk among Asian adults. The definitions for short and normal sleep durations were derived from the respective studies. The random effects model was utilized to pool effect estimates, and all statistical analyses were conducted using Review Manager 5.4 software (RevMan) (Cochrane Collaboration, Oxford, UK). Results from a systematic search obtained seven studies assessing sleep duration and hypertension risk in Asian populations. Based on a meta-analysis of six studies, short sleep duration is associated with a higher hypertension risk when compared to normal sleep duration (OR: 1.36; 95% CI: 1.13-1.64; p: 0.0010; I2: 75%). Subgroup analysis based on sex showed that the association is evident across males (OR: 1.12; 95% CI: 1.01-1.25; p: 0.03; I2: 64%) and females (OR: 1.22; 95% CI: 1.10-1.35; p: 0.0003; I2: 82%). In conclusion, based on the analyzed studies, short sleep duration is associated with a higher mild risk of hypertension, irrespective of sex. Thus, short sleep duration can be a modifiable risk factor that can be prevented to reduce the risk of hypertension. By incorporating sleep hygiene practices and promoting healthy sleep habits, significant improvement in cardiovascular health can be made, especially in hypertension risk at a population level. Further studies on the effect of sleep duration in different age populations should be conducted to confirm the impact of short sleep duration.

Health position paper and redox perspectives - Disease burden by transportation noise

Transportation noise is a ubiquitous urban exposure. In 2018, the World Health Organization concluded that chronic exposure to road traffic noise is a risk factor for ischemic heart disease. In contrast, they concluded that the quality of evidence for a link to other diseases was very low to moderate. Since then, several studies on the impact of noise on various diseases have been published. Also, studies investigating the mechanistic pathways underlying noise-induced health effects are emerging. We review the current evidence regarding effects of noise on health and the related disease-mechanisms. Several high-quality cohort studies consistently found road traffic noise to be associated with a higher risk of ischemic heart disease, heart failure, diabetes, and all-cause mortality. Furthermore, recent studies have indicated that road traffic and railway noise may increase the risk of diseases not commonly investigated in an environmental noise context, including breast cancer, dementia, and tinnitus. The harmful effects of noise are related to activation of a physiological stress response and nighttime sleep disturbance. Oxidative stress and inflammation downstream of stress hormone signaling and dysregulated circadian rhythms are identified as major disease-relevant pathomechanistic drivers. We discuss the role of reactive oxygen species and present results from antioxidant interventions. Lastly, we provide an overview of oxidative stress markers and adverse redox processes reported for noise-exposed animals and humans. This position paper summarizes all available epidemiological, clinical, and preclinical evidence of transportation noise as an important environmental risk factor for public health and discusses its implications on the population level.

Pressure Building Against the Clock: The Impact of Circadian Misalignment on Blood Pressure

PURPOSE OF REVIEW

Misalignment between the endogenous biological timing system and behavioral activities (i.e., sleep/wake, eating, activity) contributes to adverse cardiovascular health. In this review, we discuss the effects of recurring circadian misalignment on blood pressure regulation and the implications for hypertension development. Additionally, we highlight emerging therapeutic approaches designed to mitigate the negative cardiovascular consequences elicited by circadian disruption.

RECENT FINDINGS

Circadian misalignment elicited by work schedules that require individuals to be awake during the biological night (i.e., shift work) alters 24-h blood pressure rhythms. Mechanistically, circadian misalignment appears to alter blood pressure via changes in autonomic nervous system balance, variations to sodium retention, dysregulation of endothelial vasodilatory responsiveness, and activation of proinflammatory mechanisms. Recurring circadian misalignment produced by a mismatch in sleep timing on free days vs. work days (i.e., social jetlag) appears to have no direct effects on prevailing blood pressure levels in healthy adults; though, circadian disruptions resulting from social jetlag may increase the risk of hypertension through enhanced sympathetic activation and/or obesity. Furthermore, social jetlag assessment may be a useful metric in shift work populations where the magnitude of circadian misalignment may be greater than in the general population. Circadian misalignment promotes unfavorable changes to 24-h blood pressure rhythms, most notably in shift working populations. While light therapy, melatonin supplementation, and the timing of drug administration may improve cardiovascular outcomes, interventions designed to target the effects of circadian misalignment on blood pressure regulation are warranted.

An Update on Sleep Duration, Obesity, and Mortality Risk in Women

Sleep health is an essential component to overall health. Because of numerous societal, economic, and biological factors, obtaining adequate sleep poses a unique challenge to aging women. Yet, women have been traditionally understudied in sleep research. An increasing body of research supports abnormal sleep duration as a risk factor for obesity, cardiovascular disease, and mortality. This review focuses specifically on 3 areas of the discussion of insufficient sleep in women: (1) the mysterious poor health of long sleepers, (2) the potential underlying mechanisms linking abnormal sleep duration and cardiometabolic health, and (3) the need to investigate multiple levels of social determinants driving sleep disparities.

The 24-h activity cycle and cardiovascular outcomes: establishing biological plausibility using arterial stiffness as an intermediate outcome

This review proposes a biologically plausible working model for the relationship between the 24-h activity cycle (24-HAC) and cardiovascular disease. The 24-HAC encompasses moderate-to-vigorous physical activity (MVPA), light physical activity, sedentary behavior (SB), and sleep. MVPA confers the greatest relative cardioprotective effect, when considering MVPA represents just 2% of the day if physical activity guidelines (30 min/day) are met. While we have well-established guidelines for MVPA, those for the remaining activity behaviors are vague. The vague guidelines are attributable to our limited mechanistic understanding of the independent and additive effects of these behaviors on the cardiovascular system. Our proposed biological model places arterial stiffness, a measure of vascular aging, as the key intermediate outcome. Starting with prolonged exposure to SB or static standing, we propose that the reported transient increases in arterial stiffness are driven by a cascade of negative hemodynamic effects following venous pooling. The subsequent autonomic, metabolic, and hormonal changes further impair vascular function. Vascular dysfunction can be offset by using mechanistic-informed interruption strategies and by engaging in protective behaviors throughout the day. Physical activity, especially MVPA, can confer protection by chronically improving endothelial function and associated protective mechanisms. Conversely, poor sleep, especially in duration and quality, negatively affects hormonal, metabolic, autonomic, and hemodynamic variables that can confound the physiological responses to next-day activity behaviors. Our hope is that the proposed biologically plausible working model will assist in furthering our understanding of the effects of these complex, interrelated activity behaviors on the cardiovascular system.

Shift Work is Associated with an Elevated White Blood Cell Count: A Systematic Review and Meta-Analysis

The white blood cell (WBC) count increases significantly in reaction to infections and certain chronic diseases. Shift employment increases the risk for chronic low-grade inflammation and the progression of several chronic diseases. The objective of this study was to systematically evaluate the evidence from studies on total and differential WBC counts in shift employees. A literature search was performed in PubMed®, Web of Science, and Scopus databases using keywords for research published before March 1, 2022. A meta-analysis was conducted for total and differential WBC counts using a random-effects approach. A total of 25 studies covering a sample of 37,708 day and shift employees were included in this review. The studies represented America, Europe, East Asia, and Middle East. A significant increase in the total counts (×109/L) of WBC [mean difference (MD) = 0.43; 95% confidence interval (CI): 0.34-0.52; P < 0.001], lymphocytes (MD = 0.16; 95% CI: 0.02-0.30; P = 0.02), monocytes (MD = 0.04; 95% CI: 0-0.07; P = 0.03), and eosinophils (MD = 0.01; 95% CI: 0-0.01; P = 0.03) was observed in shift workers compared to the day counterparts. However, neutrophils and basophils were not significantly different between the groups. Shift work significantly increases the total and differential blood counts in peripheral circulation. Therefore, total and differential WBC counts represent a relatively inexpensive biomarker for diagnostics and prognostics of diseases in shift workers.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

Assessment of lifestyle "vital signs" in healthcare settings

Unhealthy lifestyles, such as maintenance of poor diets and physical inactivity, are a powerful driver of disease-producing risk factors and chronic illnesses. This has led to an increasing call to assess adverse lifestyle factors in healthcare settings. This approach could be aided by designating health-related lifestyle factors as "vital signs" that can be recorded during patient visits. Just such an approach has been used for assessing patients' smoking habits since the 1990s. In this review, we assess the rationale for addressing six other health-related lifestyle factors, beyond smoking, in patient care settings: physical activity (PA), sedentary behavior (SB), participation in muscle strengthening exercises, mobility limitations, diet, and sleep quality. For each domain, we evaluate the evidence that supports currently proposed ultra-short screening tools. Our analysis indicates strong medical evidence to support the use of one to two-item screening questions for assessing patients' PA, SB, muscle strengthening activities, and presence of "pre-clinical" mobility limitations. We also present a theoretical basis for measuring patients' diet quality through use of an ultrashort dietary screen, based on evaluation of healthy food intake (fruits/vegetables) and unhealthy food intake (high consumption of highly processed meats and/or consumption of sugary foods and beverages) and a proposed evaluation of sleep quality using a single-item screener. The result is a 10-item lifestyle questionnaire that is based on patient self-report. As such, this questionnaire has the potential to be employed as a practical tool for assessing health behaviors in clinical care settings without impairing the normal workflow of healthcare providers.

Investigation of the role of sleep and physical activity for chronic disease prevalence and incidence in older Irish adults

Background

Chronic diseases are the leading cause of death worldwide. Many of these diseases have modifiable risk factors, including physical activity and sleep, and may be preventable. This study investigated independent associations of physical activity and sleep with eight common chronic illnesses.

Methods

Data were from waves 1, 3 and 5 of The Irish Longitudinal Study on Ageing (n = 5,680). Inverse probability weighted general estimating equations were used to examine longitudinal lifetime prevalence and cumulative incidence of self-reported conditions.

Results

Sleep problems were significantly associated with increased odds of incident and prevalent arthritis and angina. Additionally sleep problems were associated with higher odds of lifetime prevalence of hypertension and diabetes. Physical activity was negatively associated incident osteoporosis and respiratory diseases and negatively associated with lifetime prevalence of hypertension, high cholesterol and diabetes.

Conclusions

Worse sleep quality and lower physical activity were associated with higher odds of chronic diseases. Interventions to improve sleep and physical activity may improve health outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-14108-6.

Sleep duration irregularity is associated with elevated blood pressure in young adults

Sleep irregularity (i.e., highly variable sleep patterns) is an emerging risk factor for cardiometabolic disease. Though irregular sleep patterns are common among young adults, the cardiometabolic health (CMH) repercussions of sleep irregularity in this population are unclear. We examined associations between sleep duration and irregularity with measures of CMH in 44 (24 M/20 F, 23 ± 5y, BMI 26 ± 4 kg/m², blood pressure (BP): 125/71 ± 14/9 mmHg) young adults. Participants wore actigraphy monitors for seven-days and sleep duration irregularity was operationalized as the standard deviation of nightly sleep duration (sleep SD). CMH variables of interest included brachial and aortic BP, arterial stiffness (cf-PWV), augmentation index (AIx75), and fasting blood glucose and lipids. Associations between sleep duration and sleep SD with CMH variables were assessed via correlations adjusted for sex and BMI. Sleep duration generally was not associated with CMH indices. However, sleep SD was associated with brachial systolic (r = 0.433, p = .027) and diastolic BP (r = 0.415, p = .035). Similarly, sleep duration SD was associated with aortic systolic BP (r = 0.447, p = .022). Our findings show that sleep irregularity, but not duration, is associated with higher brachial and central BP in young adults.Abbreviations: AIx75: augmentation index at a heart rate of 75 beats per minute; BP: blood pressure; CMH: cardiometabolic health; cf-PWV: carotid-femoral pulse wave velocity; DXA: dual x-ray absorptiometry; mg/dl: milligrams per deciliter; PWA: pulse wave analysis; PWV: pulse wave velocity; sleep duration SD: standard deviation of nightly sleep duration.

A review article of the cardiovascular sequalae in esport athletes: a cause for concern?

The esports industry has grown exponentially and is expected to flourish rapidly in the coming years. Awareness about the cardiovascular sequalae in elite esport athletes has gained considerable momentum. Evidence supporting systematic screening in esport athletes is however lacking. In this narrative review, we discuss potential negative health effects on the cardiovascular system in esports enthusiasts. The pathophysiological mechanisms discussed in this narrative review may put esport athletes at an increased risk of cardiovascular events. Although large studies in esport athletes to substantiate these claims are inexistent, case reports or case-controlled studies have been included to support our hypotheses. Sleep deprivation, psychological stress, altered arterial stiffness, hypertension, and heart rate variability are some of these proposed mechanisms. The available data is unfortunately extrapolated from small cohorts. Nevertheless, the risk of sudden cardiac death is an important health concern which should be addressed appropriately. This review will raise awareness about the possible negative impact on the cardiovascular system in esport athletes.

Sleep Deficiency and Cardiometabolic Disease

Epidemiologic studies have demonstrated that short sleep duration is associated with an increased risk of cardio-metabolic health outcomes including cardiovascular disease mortality, coronary heart disease, type 2 diabetes mellitus, hypertension, and metabolic syndrome. Experimental sleep restriction studies have sought to explain these findings. This review describes the main evidence of these associations and possible mechanisms explaining them. Whether sleep extension reverses these now widely acknowledged adverse health effects and the feasibility of implementing such strategies on a public health level is discussed.

The Endothelium as a Hub for Cellular Communication in Atherogenesis: Is There Directionality to the Message?

Endothelial cells line every blood vessel and thereby serve as an interface between the blood and the vessel wall. They have critical functions for maintaining homeostasis and orchestrating vascular pathogenesis. Atherosclerosis is a chronic disease where cholesterol and inflammatory cells accumulate in the artery wall below the endothelial layer and ultimately form plaques that can either progress to occlude the lumen or rupture with thromboembolic consequences - common outcomes being myocardial infarction and stroke. Cellular communication lies at the core of this process. In this review, we discuss traditional (e.g., cytokines, chemokines, nitric oxide) and novel (e.g., extracellular vesicles) modes of endothelial communication with other endothelial cells as well as circulating and vessel wall cells, including monocytes, macrophages, neutrophils, vascular smooth muscle cells and other immune cells, in the context of atherosclerosis. More recently, the growing appreciation of endothelial cell plasticity during atherogenesis suggests that communication strategies are not static. Here, emerging data on transcriptomics in cells during the development of atherosclerosis are considered in the context of how this might inform altered cell-cell communication. Given the unique position of the endothelium as a boundary layer that is activated in regions overlying vascular inflammation and atherosclerotic plaque, there is a potential to exploit the unique features of this group of cells to deliver therapeutics that target the cellular crosstalk at the core of atherosclerotic disease. Data are discussed supporting this concept, as well as inherent pitfalls. Finally, we briefly review the literature for other regions of the body (e.g., gut epithelium) where cells similarly exist as a boundary layer but provide discrete messages to each compartment to govern homeostasis and disease. In this light, the potential for endothelial cells to communicate in a directional manner is explored, along with the implications of this concept - from fundamental experimental design to biomarker potential and therapeutic targets.

Effects of Acute Partial Sleep Deprivation and High-Intensity Interval Exercise on Postprandial Network Interactions

Introduction: High-intensity interval exercise (HIIE) is deemed effective for cardiovascular and autonomic nervous system (ANS) health-related benefits, while ANS disturbance increases the risk for cardiovascular disease (CVD). Postprandial lipemia and acute-partial sleep deprivation (APSD) are considered as CVD risk factors due to their respective changes in ANS. Exercising in the morning hours after APSD and have a high-fat breakfast afterwards may alter the interactions of the cardiovascular, autonomic regulation, and postprandial lipemic systems threatening individuals' health. This study examined postprandial network interactions between autonomic regulation through heart rate variability (HRV) and lipemia via low-density lipoprotein (LDL) cholesterol in response to APSD and HIIE. Methods: Fifteen apparently healthy and habitually good sleepers (age 31 ± 5.2 SD yrs) completed an acute bout of an isocaloric HIIE (in form of 3:2 work-to-rest ratio at 90 and 40% of VO2 reserve) after both a reference sleep (RSX) and 3-3.5 h of acute-partial sleep deprivation (SSX) conditions. HRV time and frequency domains and LDL were evaluated in six and seven time points surrounding sleep and exercise, respectively. To identify postprandial network interactions, we constructed one correlation analysis and one physiological network for each experimental condition. To quantify the interactions within the physiological networks, we also computed the number of links (i.e., number of significant correlations). Results: We observed an irruption of negative links (i.e., negative correlations) between HRV and LDL in the SSX physiological network compared to RSX. Discussion: We recognize that a correlation analysis does not constitute a true network analysis due to the absence of analysis of a time series of the original examined physiological variables. Nonetheless, the presence of negative links in SSX reflected the impact of sleep deprivation on the autonomic regulation and lipemia and, thus, revealed the inability of HIIE to remain cardioprotective under APSD. These findings underlie the need to further investigate the effects of APSD and HIIE on the interactions among physiological systems.

Racial and ethnic disparities in cardiometabolic disease and COVID-19 outcomes in White, Black/African American, and Latinx populations: Social determinants of health

Racial and ethnic-related health disparities in the United States have been intensified by the greater burden of Coronavirus Disease 2019 (COVID-19) in racial and ethnic minority populations. Compared to non-Hispanic White individuals, non-Hispanic Black and Hispanic/Latinx individuals infected by COVID-19 are at greater risk for hospitalization, intensive care unit admission, and death. There are several factors that may contribute to disparities in COVID-19-related severity and outcomes in these minority populations, including the greater burden of cardiovascular and metabolic diseases as discussed in our companion review article. Social determinants of health are a critical, yet often overlooked, contributor to racial and ethnic-related health disparities in non-Hispanic Black and Hispanic/Latinx individuals relative to non-Hispanic White individuals. Thus, the purpose of this review is to focus on the essential role of social factors in contributing to health disparities in chronic diseases and COVID-19 outcomes in minority populations. Herein, we begin by focusing on structural racism as a social determinant of health at the societal level that contributes to health disparities through downstream social level (e.g., occupation and residential conditions) and individual level health behaviors (e.g., nutrition, physical activity, and sleep). Lastly, we conclude with a discussion of practical applications and recommendations for future research and public health efforts that seek to reduce health disparities and overall disease burden.

Effect of five nights of sleep extension on peripheral vascular function: a randomized crossover investigation into long sleep duration

Long sleep duration, defined as ≥9 h, is associated with increased cardiovascular mortality. We sought to determine the effect of sleep extension on peripheral vascular health. Twelve middle-aged adults were randomly assigned to spend five nights with 8 h (control) or 10+ hours time in bed (TIB) in a crossover fashion. Sleep was assessed using wrist actigraphy. Peak reactive hyperemia in the forearm was measured using venous-occlusion plethysmography as an index of microvascular vasodilation. Nighttime and morning blood pressure was recorded along with pulse wave velocity (arterial stiffness). Average sleep duration was 7.1 ± 0.3 and 9.3 ± 0.3 h for 8 and 10+ hours TIB (P < 0.001), respectfully. On average, sleep was extended by 127 ± 29 min with nine participants reaching average sleep durations >9 h. Extended sleep did not change nighttime or morning blood pressure, or pulse wave velocity (all P > 0.05). In contrast, peak forearm vascular conductance (FVC, 0.27 ± 0.08 vs. 0.23 ± 0.07 ml/100 ml/min/mmHg, P = 0.02) and total excess blood flow (28 ± 9 vs. 24 ± 11 ml/100 ml, P < 0.01) were increased following sleep extension. The change in FVC and total excess blood flow were inversely correlated with the change in wake after sleep onset and TIB (both r = -0.62, P < 0.05), but not with sleep duration. These results demonstrate that extended time in bed accompanied by long sleep durations does not impair peripheral vascular function, but rather, may increase microvasculature vasodilatory capacity in midlife adults.

Sex-specific association of sleep duration with subclinical indicators of metabolic diseases among asymptomatic adults

Background

Accumulating evidence suggests sleep duration may be involved in metabolic regulation. However, studies regarding the association with the early stage of the metabolic disease are limited, and the findings were inconsistent.

Methods

A study among 4922 asymptomatic adults was conducted based on a Chinese national survey in 2009. The early stage of metabolic diseases was evaluated using three proxies: triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C), the product of triglyceride and fasting glucose (TyG), and lipid accumulation product (LAP). Multivariable linear and logistic regression models were used to explore the associations of sleep duration with the three indicators.

Results

The linear regression models revealed that, among females, sleep duration <7 h per day, compared with 7-9 h, was associated with an increased value of LAP and TyG by 25.232% (95%CI: 10.738%, 41.623%) and 0.104 (95%CI: 0.024, 0.185), respectively, in the crude model. The effects were attenuated but remained significant for LAP (11.405%; 95%CI: 1.613%, 22.262%). Similarly, the logistic regression models further found that sleep duration <7 h per day could increase the risk of elevated LAP (OR: 1.725, 95CI%:1.042, 2.856) after adjusting for multiple covariates. By contrast, no associations were found among males.

Conclusions

Short sleep duration was associated with subclinical indicators of metabolic diseases, and females were more susceptible to the association.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01626-w.

Sleep Duration and Hypertension: Epidemiological Evidence and Underlying Mechanisms

While the contribution of several physiological systems to arterial blood pressure regulation has been studied extensively, the role of normal and disrupted sleep as a modifiable determinant of blood pressure control, and in the pathophysiology of hypertension, has only recently emerged. Several sleep disorders, including sleep apnea and insomnia, are thought to contribute to the development of hypertension, although less attention is paid to the relationship between sleep duration and blood pressure independent of sleep disorders per se. Accordingly, this review focuses principally on the physiology of sleep and the consequences of abnormal sleep duration both experimentally and at the population level. Clinical implications for patients with insomnia who may or may not have abbreviated sleep duration are explored. As a corollary, we further review studies of the effects of sleep extension on blood pressure regulation. We also discuss epidemiological evidence suggesting that long sleep may also be associated with hypertension and describe the parabolic relationship between total sleep time and blood pressure. We conclude by highlighting gaps in the literature regarding the potential role of gut microbial health in the cross-communication of lifestyle patterns (exercise, diet, and sleep) with blood pressure regulation. Additionally, we discuss populations at increased risk of short sleep, and specifically the need to understand mechanisms and therapeutic opportunities in women, pregnancy, the elderly, and in African Americans.

Short Sleep Duration and Erectile Dysfunction: A Review of the Literature

The meaning of sleep has puzzled people for millennia. In modern society, short sleep duration is becoming a global problem. It has been established that short sleep duration can increase the risk of several diseases, such as cardiovascular and metabolic diseases. Currently, a growing body of research has revealed a possible link between sleep disorders and erectile dysfunction (ED). However, the mechanisms linking short sleep duration and ED are largely unknown. Thus, we provide a review of clinical trials and animal studies. In this review, we propose putative pathways connecting short sleep duration and ED, including neuroendocrine pathways and molecular mechanisms, aiming to pave the way for future research. Meanwhile, the assessment and improvement of sleep quality should be recommended in the diagnosis and treatment of ED patients.

Acute Myocardial Infarction and Daylight Saving Time Transitions: Is There a Risk?

Available evidence on the risk of acute myocardial infarction (AMI) in the days after the spring daylight saving time (DST) transition suggests either a modest increase or no risk increase. Partial sleep deprivation and enhanced circadian clock misalignment have been implicated as the underlying mechanisms for increased AMI risk, probably via enhanced thrombo-inflammatory processes and activation of the sympathetic nervous system. Most of the studies, as we suggest as a perspective here, have used potentially inappropriate control periods, including the two post-transitional weeks, because adjustment after the spring DST transition lasts at least four weeks for all chronotypes and probably even beyond this period for late chronotypes. The most plausible conclusions, at the moment, for the risk of AMI after the spring DST transition are: (1) the risk is increased, (2) a relatively modest risk increase could be currently underestimated or in some studies undetected, (3) late chronotypes and/or individuals with high levels of social jetlag (a proxy for circadian clock misalignment) could be more affected by the phenomenon, and (4) underlying pathophysiological mechanisms should be further explored. As a significant part of world’s population continues to be affected by the biannual clock change, the question of increased AMI risk in the post-transitional period remains an intriguing public health issue.

Sleep deprivation alters task-related changes in functional connectivity of the frontal cortex: A near-infrared spectroscopy study

Sleep deprivation (SD) is known to be associated with decreased cognitive performance; however, the underlying mechanisms are poorly understood. As interactions between distinct brain regions depend on mental state, functional brain networks established by these connections typically show a reorganization during task. Hence, analysis of functional connectivity (FC) could reveal the task-related change in the examined frontal brain networks. Our objective was to assess the impact of SD on static FC in the prefrontal and motor cortices and find whether changes in FC correlate with changes in neuropsychological scores. Healthy young male individuals (n = 10, 27.6 ± 3.7 years of age) participated in the study. A battery of tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) and 48 channel functional near-infrared spectroscopy (fNIRS) measurements were performed before and after 24 hr of SD. Network metrics were obtained by graph theoretical analysis using the fNIRS records in resting state and during finger-tapping sessions. During task, SD resulted in a significantly smaller decrease in the number and strength of functional connections (characterizing FC) in the frontal cortex. Changes in the global connection strengths correlated with decreased performance in the paired association learning test. These results indicate a global impact of SD on functional brain networks in the frontal lobes.

Effects of Experimental Sleep Restriction on Ambulatory and Sleep Blood Pressure in Healthy Young Adults: A Randomized Crossover Study

[Figure: see text].

The thrombotic risk of spaceflight: has a serious problem been overlooked for more than half of a century?

The first ever venous thrombotic condition associated with spaceflight, an internal jugular vein thrombus requiring anticoagulation, has recently been reported. Systematic investigation of space travel-associated thrombotic risk has not been conducted. Cellular, animal, and human studies performed in ground-based models and in actual weightlessness revealed influences of weightlessness and gravity on the blood coagulation system. However, human study populations were small and limited to highly selected participants. Evidence in individuals with medical conditions and older persons is lacking. Evidence for thrombotic risk in spaceflight is unsatisfactory. This issue deserves further study in heterogeneous, high risk populations to find prevention strategies and to enable safe governmental and touristic human spaceflight.

Macro- and microvascular reactivity during repetitive exposure to shortened sleep: sex differences

Epidemiological studies have reported strong association between sleep loss and hypertension with unknown mechanisms. This study investigated macrovascular and microcirculation changes and inflammatory markers during repetitive sleep restriction. Sex differences were also explored. Forty-five participants completed a 22-day in-hospital protocol. Participants were assigned to, (1) eight-hour sleep per night (control), or (2) sleep restriction (SR) condition: participants slept from 0300 to 0700 h for three nights followed by a recovery night of 8-h sleep, repeated four times. Macrocirculation assessed by flow mediated dilation (FMD) and microcirculation reactivity tests were performed at baseline, last day of each experimental block and during recovery at the end. Cell adhesion molecules and inflammatory marker levels were measured in blood samples. No duration of deprivation (SR block) by condition interaction effects were found for FMD, microcirculation, norepinephrine, cell adhesion molecules, IL-6 or IL-8. However, when men and women were analyzed separately, there was a statistical trend (p = 0.08) for increased IL-6 across SR blocks in women, but not in men. Interestingly, men showed a significant progressive (dose dependent) increase in skin vasodilatation (p = 0.02). A novel and unexpected finding was that during the recovery period, men that had been exposed to repeated SR blocks had elevated IL-8 and decreased norepinephrine. Macrocirculation, microcirculation, cell adhesion molecules, and markers of inflammation appeared to be resistant to this model of short-term repetitive exposures to the blocks of shortened sleep in healthy sleepers. However, men and women responded differently, with women showing mild inflammatory response and men showing more vascular system sensitivity to the repetitive SR.

Sleep duration and vascular inflammation using hybrid positron emission tomography/magnetic resonance imaging: results from the Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

Short sleep duration (SD) is associated with cardiovascular disease (CVD). We investigated the relationship between objective SD and subclinical atherosclerosis employing hybrid PET/MRI with ¹⁸F-FDG tracer in the MESA cohort.

METHODS

We utilized data from MESA-SLEEP and MESA-PET ancillary studies. SD and sleep fragmentation index (SFI) were assessed using 7-day actigraphy. The primary and secondary outcomes were carotid inflammation, defined using target-to-background ratios (TBR), and measures of carotid wall remodeling (carotid wall thickness [CWT]), summarized by SD category. Multivariate linear regression was performed to assess the association between SD and SFI with the primary/secondary outcomes, adjusting for several covariates including apnea-hypopnea index (AHI), and CVD risk.

RESULTS

Our analytical sample (n=58) was 62% female (mean age 68±8.4 years). Average SD was 5.1±0.9 hours in the short SD group (≤6 hours/night, 31%), and 7.1±0.8 hours in the normal SD group (69%). Prevalence of pathologic vascular inflammation (TBRmax>1.6) was higher in the short SD group (89% vs. 53%, p=0.009). Those with short SD had a higher TBRmax (1.77 vs 1.71), though this was not statistically significant (p=0.39). CWT was positively correlated with SFI even after adjusting for covariates (Beta [SE]=0.073±[0.032], p=0.025).

CONCLUSIONS

Prevalence of pathologic vascular inflammation was higher among those who slept ≤6 hours, and vascular inflammation was higher among those with a SD of ≤6 hours. Interestingly, SFI was positively correlated with CWT even after adjustment for covariates. Our results are hypothesis-generating but suggest that both habitual SD and SFI should be investigated in future studies as potential risk factors for subclinical atherosclerosis.

Sleep duration regularity, but not sleep duration, is associated with microvascular function in college students

STUDY OBJECTIVES

Vascular dysfunction is a hypothesized mechanism linking poor sleep habits to an increased incidence of cardiovascular diseases (CVDs). However, the vascular profile associated with free-living sleep duration and sleep regularity has not been well elucidated, particularly in young adults. Thus, this study aimed to evaluate the associations between mean sleep duration, regularity in sleep duration, and peripheral vascular function in young adult college students.

METHODS

Fifty-one healthy undergraduate students (20 ± 1 years) completed 14 days of 24-hour wrist actigraphy and subsequent vascular assessments. Macrovascular function was measured using brachial artery flow-mediated dilation (FMD) while microvascular function was measured via passive leg movement (PLM).

RESULTS

Mean sleep duration was unrelated to FMD and PLM. Conversely, more irregular sleep duration (14-day sleep duration standard deviation [SD]) was unfavorably associated with all three measures of PLM-induced hyperemia (peak leg blood flow [LBF], p = 0.01; change in LBF from baseline to peak, p < 0.01; LBF area under the curve, p < 0.01), and remained significant in regression models which adjusted for sex, body mass index, blood pressure, physical activity, alcohol and caffeine consumption, and sleep duration (all p < 0.05). When using a median split to dichotomize "low" and "high" sleep duration SD groups, those demonstrating high variability in sleep duration exhibited ~45% lower PLM responses compared with those demonstrating low variability.

CONCLUSIONS

Irregular sleep duration is associated with poorer microvascular function as early as young adulthood. These findings support the growing body of evidence that irregular sleep patterns may be an independent and modifiable risk factor for CVD.

Effects of sleep deprivation on endothelial function in adult humans: a systematic review

Sleep deprivation is highly prevalent and is associated with increased cardiovascular disease (CVD) morbidity and mortality. Age-related alterations in sleep and chronobiology may exaggerate CVD susceptibility in older individuals. The mechanisms responsible for the association between sleep deprivation and CVD are not fully understood, but endothelial dysfunction may play a central role. Our objective was to conduct a systematic literature review to evaluate the evidence on the effects of sleep deprivation on endothelial function (EF). This review adhered to the PRISMA guidelines and was pre-registered with PROSPERO (#CRD42020192485, 07/24/2020). We searched PubMed, Web of Science, Embase, and Cochrane Library for articles published through May 1, 2020. Eligibility criteria included publication in English and use of well-established EF methodologies in adult humans. Two investigators independently performed the literature search, study selection, data extraction, risk-of-bias assessment, and qualitative data synthesis. Out of 3571 articles identified, 24 articles were included in the systematic review. Main findings include the following: (1) shorter sleep duration is associated with lower macrovascular EF; (2) not sleeping 7-9 h/night is linked with impaired microvascular EF; (3) sleep restriction impairs micro- and macrovascular EF; (4) acute total sleep deprivation impairs micro- and macrovascular EF but data on macrovascular EF are less consistent; and (5) shift work impairs macrovascular EF. In conclusion, sleep deprivation impairs EF, which may explain the link between insufficient sleep and CVD. Future investigations should fully elucidate the underlying mechanisms and develop strategies to combat the adverse endothelial effects of sleep deprivation across the lifespan.

The impact of the 24-h movement spectrum on vascular remodeling in older men and women: a review

Aging is associated with increased risk of cardiovascular and cerebrovascular events, which are preceded by early, negative remodeling of the vasculature. Low physical activity is a well-established risk factor associated with the incidence and development of disease. However, recent physical activity literature indicates the importance of considering the 24-h movement spectrum. Therefore, the purpose of this review was to examine the impact of the 24-h movement spectrum, specifically physical activity (aerobic and resistance training), sedentary behavior, and sleep, on cardiovascular and cerebrovascular outcomes in older adults, with a focus on recent evidence (<10 yr) and sex-based considerations. The review identifies that both aerobic training and being physically active (compared with sedentary) are associated with improvements in endothelial function, arterial stiffness, and cerebrovascular function. Additionally, there is evidence of sex-based differences in endothelial function: a blunted improvement in aerobic training in postmenopausal women compared with men. While minimal research has been conducted in older adults, resistance training does not appear to influence arterial stiffness. Poor sleep quantity or quality are associated with both impaired endothelial function and increased arterial stiffness. Finally, the review highlights mechanistic pathways involved in the regulation of vascular and cerebrovascular function, specifically the balance between pro- and antiatherogenic factors, which mediate the relationship between the 24-h movement spectrum and vascular outcomes. Finally, this review proposes future research directions: examining the role of duration and intensity of training, combining aerobic and resistance training, and exploration of sex-based differences in cardiovascular and cerebrovascular outcomes.

Regular aerobic exercise counteracts endothelial vasomotor dysfunction associated with insufficient sleep

Insufficient sleep is associated with endothelial vasomotor dysfunction and increased cardiovascular risk. Regular aerobic exercise is an effective lifestyle strategy for improving endothelial function and, in turn, reducing cardiovascular risk. We tested the hypotheses that regular aerobic exercise would 1) improve endothelial vasodilation and 2) decrease endothelin (ET)-1-mediated vasoconstrictor tone in middle-aged adults who chronically sleep <7 h/night. Thirty-six healthy, middle-aged adults were studied: 16 with normal sleep duration (age: 57 ± 2 yr; sleep duration: 7.4 ± 0.1 h/night) and 20 with short sleep duration (age: 56 ± 1 yr; sleep duration: 6.2 ± 0.1 h/night). The 20 short sleepers completed a 3-mo aerobic exercise training intervention. Forearm blood flow was determined (via plethysmography) in response to intra-arterial acetylcholine (ACh), BQ-123 (ET_A receptor antagonist), ACh + BQ-123, and sodium nitroprusside. Forearm blood flow responses to ACh were lower (∼20%; P < 0.05) in the short (from 4.2 ± 0.2 to 10.5 ± 0.6 mL/100 mL tissue/min) versus normal (4.2 ± 0.2 to 12.7 ± 0.6 mL/100 mL tissue/min) sleepers. In response to BQ-123, the short-sleep group had a significantly greater increase in resting forearm blood flow than the normal-sleep group (∼25% vs. ∼8%). ACh + BQ-123 resulted in a significant (∼25%) increase in the ACh-mediated vasodilation in the short-sleep group only. After exercise training, although nightly sleep duration was unchanged (6.4 ± 0.1 h/night), ACh-mediated vasodilation was significantly higher (∼20%), ET-1-mediated vasoconstriction was significantly lower (∼80%), and the vasodilator response to ACh was not increased with ET_A receptor blockade. Regular aerobic exercise, independent of changes in nightly sleep duration, can counteract insufficient sleep-related endothelial vasomotor dysfunction.NEW & NOTEWORTHY Habitual insufficient nightly sleep (<7 h/night) is associated with increased risk of cardiovascular disease and events. Endothelial dysfunction, specifically reduced endothelium-dependent vasodilation and increased endothelin (ET)-1-mediated vasoconstriction, is considered to be a major contributing mechanism underlying increased vascular risk with insufficient sleep. In contrast to insufficient sleep, regular aerobic exercise enhances endothelial vasomotor function, reducing the risk of cardiovascular disease and associated events. In the present study, we determined the effects of aerobic exercise training on endothelium-dependent vasodilation and ET-1 vasoconstriction in adults who habitually sleep <7 h/night. After exercise training, although nightly sleep duration was unchanged, endothelium-dependent vasodilation was significantly enhanced and ET-1-mediated vasoconstrictor tone was significantly reduced in adults who sleep <7 h/night. Regular aerobic exercise training can mitigate insufficient sleep-related endothelial vasomotor dysfunction and, in turn, potentially reduce the cardiovascular risk associated with habitual insufficient nightly sleep.

The Association Between Sleep and Metabolic Syndrome: A Systematic Review and Meta-Analysis

PURPOSE

Sleep duration is thought to play a key role in the development of metabolic syndrome. However, the results have been inconsistent.

METHODS

We conducted a systematic review and meta-analysis of cohort studies and searched publications in PubMed, Embase, Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov. The summary relative risks (RRs) were estimated using a random model. The sensitivity analysis was performed by sequentially excluding each study to test the robustness of the pooled estimates.

FINDING

We included 13 studies involving 300,202 patients in which short sleep and long sleep significantly increased the risk of metabolic syndrome 15% (RR = 1.15, 95%CI = 1.09-1.22, p < 0.001) and 19% (RR = 1.19, 95%CI = 1.05-1.35, p < 0.001). Moreover, the relationship between sleep duration and metabolic syndrome risk presented a U-shaped curve. Short and long sleep increased the risk of obesity by 14% (RR = 1.14, 95%CI = 1.07-1.22, p<0.001) and 15% (RR = 1.15, 95%CI = 1.00-1.30, p = 0.04), and high blood pressure 16% (RR = 1.16, 95%CI = 1.02-1.31, p = 0.03) and 13% (RR = 1.13, 95%CI = 1.04-1.24, p = 0.01), respectively. Short sleep can potentially increase the risk of high blood sugar by 12% (RR = 1.12, 95%CI = 1.00-1.15, P = 0.05).

IMPLICATIONS

Based on our findings, sleep is a behavior that can be changed and is economical. Clinically doctors and health professionals should be encouraged to increase their efforts to promote healthy sleep for all people.

Sleep deprivation and endothelial function: reconciling seminal evidence with recent perspectives

Sleep is critical for the maintenance of physiological homeostasis and, as such, inadequate sleep beckons a myriad of pathologies. Sleep deprivation is a growing health concern in contemporary society since short sleep durations are associated with increased cardiovascular disease risk and atherosclerotic plaque development. Vascular endothelial dysfunction is an antecedent to atherosclerosis and cardiovascular disease. Herein, we review seminal literature indicating that short sleep durations attenuate endothelial function and explore more recent evidence indicating that sleep deprivation perturbs autonomic balance and the circadian rhythmicity of peripheral vascular clock components. We further examine literature that indicates a mechanistic link between short sleep duration and endothelial dysfunction and subsequent morbidity. Understanding the mechanisms that regulate endothelial function in the context of sleep deprivation facilitates the development and optimization of interventions, such as exercise, that mitigate the ramifications of inadequate sleep on vascular function and cardiovascular health.Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/sleep-deprivation-and-endothelial-function/.

Acute partial sleep deprivation and high-intensity interval exercise effects on postprandial endothelial function

PURPOSE

Acute-total and chronic-partial sleep deprivation increase the risks for cardiovascular disease (CVD). Cardiovascular function assessed by flow mediated dilation (FMD) is reduced after sleep deprivation. High-intensity interval exercise (HIIE) improves postprandial FMD. Sleep-deprived individuals may practice HIIE followed by a high-fat breakfast. This study investigated the acute-partial sleep deprivation (APSD) and HIIE interaction on postprandial FMD.

METHODS

Fifteen healthy males (age 31 ± 5 years) participated in: (a) reference sleep (~ 9.5 h) with no HIIE (RS), (b) RS and HIIE (RSX), and (c) APSD and HIIE (SSX). HIIE was performed in 3:2 min intervals at 90% and 40% of VO₂ reserve. FMD was assessed the night before (D1), the morning of the next day (D2), 1 h (1hrPE) and 4 h post HIIE (4hrPE).

RESULTS

FMD% change was lower at RS compared to both RSX (F_1,14 = 23.96, p < 0.001, η² = 0.631) and SSX (F_1,14 = 4.8, p = 0.47, η² = 0.253) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = 0.2, p = 0.889, η² = 0.001), but SSX elicited greater FDM responses. Absolute FMD change was lower at RS compared to both RSX (F_1,14 = 21.5, p < 0.001, η² = 0.606) and SSX (F_1,14 = 7.01, p = 0.019, η² = 0.336) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = .03, p = 0.858, η² = 0.002), but SSX elicited greater FDM responses.

CONCLUSIONS

HIIE short-term effects on cardiovascular function remain cardioprotective even after an acute-partial sleep deprivation.

Association of self-reported sleep duration and quality with BaPWV levels in hypertensive patients

The association between sleep conditions and arterial stiffness remains inconclusive. We aimed to investigate the relationship of sleep duration and quality with brachial-ankle pulse-wave velocity (baPWV) in hypertensive patients. A total of 14,485 hypertensive adults were included in this cross-sectional analysis. Information about sleep duration and quality was obtained via questionnaire. A baPWV level ≥1800 cm/s was defined as indicative of arterial stiffness. Compared with participants with a sleep duration <8 h per day, participants with a sleep duration ≥8 h per day had a significantly higher baPWV level (β = 13.7 cm/s; 95% CI: 3.9, 23.5) and a nonsignificantly higher prevalence of arterial stiffness (39.7% vs. 33.0%; OR, 1.08; 95% CI: 0.99-1.19). Similarly, compared with participants with good or medium sleep quality, participants with poor sleep quality had a significantly higher baPWV level (β = 16.3 cm/s; 95% CI: 0.1, 32.6) and a nonsignificantly greater prevalence of arterial stiffness (36.6% vs. 35.3%; OR, 1.13; 95% CI: 0.97-1.32). When sleep duration and quality were examined jointly, participants with a sleep duration ≥8 h and/or poor sleep quality had a significantly higher baPWV level (β = 14.4 cm/s; 95% CI: 5.3, 23.4) and a greater prevalence of arterial stiffness (38.8% vs. 32.7%; OR, 1.10; 95% CI: 1.01-1.20) than those with a sleep duration <8 h and good/medium sleep quality. In summary, among hypertensive patients, a longer sleep duration (≥8 h per day) and poor sleep quality were associated with higher baPWV levels and a higher prevalence of arterial stiffness.

Self-reported sleep quality is associated with central hemodynamics in healthy individuals

BACKGROUND

Insufficient sleep is associated with arterial stiffness and elevated cardiovascular disease risk. Central hemodynamics are influenced by arterial stiffness, yet independently predict cardiovascular risk. Relationships between sleep characteristics and central hemodynamic parameters are largely unexplored. We aimed to characterize the relationship between self-reported sleep quality and central hemodynamics in healthy individuals. To explore the secondary hypothesis that impairments in glucose metabolism may underlie relationships between sleep and central hemodynamic variables, we also explored associations between self-reported sleep quality and fasting blood glucose values.

METHODS

Thirty-one healthy study subjects (20 to 69 years, 17 men) were free from metabolic or cardiovascular disease and did not take sleep medication. Self-reported sleep quality was obtained using the Pittsburgh Sleep Quality Index (PSQI) with normal sleepers defined by PSQI scores 0-5 and poor sleepers by PSQI score > 5. Relationships were assessed between PSQI, central hemodynamic profiles (systolic and diastolic blood pressures, pulse and augmentation pressures, augmentation index) estimated from oscillometric pulse wave analysis, and blood glucose values.

RESULTS

Central pulse pressure was significantly elevated in poor (PSQI score > 5) compared with that in normal (PSQI scores 0-5) sleepers (P < 0.05). Linear regression models, adjusted for age, gender, and body mass index, demonstrated PSQI score to be an independent predictor (P < 0.05) of both central pulse (β = 0.469) and augmentation (β = 0.364) pressures. Global PSQI scores were not related to fasting blood glucose values (r = 0.045; P > 0.05).

CONCLUSIONS

Significant relationships between central pulse and augmentation pressures and self-reported sleep quality highlight the importance of considering sleep when examining lifestyle contributors to central hemodynamics.

Effects of Sleep Duration on Cardiovascular Events

PURPOSE OF REVIEW

Sleep is an essential component of human health, and suboptimal sleep duration has been associated with increased cardiovascular morbidity and mortality. This review summarizes physiological and pathological effects of sleep duration on the cardiovascular system.

RECENT FINDINGS

Both decreased and increased duration of sleep lead to increased cardiovascular mortality and has a U-shaped curve. Sleep apnea is an independent risk factor for atherosclerosis and hypertension, and its treatment with continuous positive airway pressure (CPAP) results in increased survival. Estimated sleep duration of 6-8 h is associated with decreased mortality and major cardiovascular events and should be addressed by clinicians during routine visits.

Post-exercise Response of Arterial Parameters for Arterial Health Assessment Using a Microfluidic Tactile Sensor and Vibration-Model-Based Analysis: A Proof-of-Concept Study

OBJECTIVE

Arterial stiffness and endothelial function are two established surrogate markers of subclinical atherosclerosis and are quantified by three arterial parameters: elasticity, viscosity and radius of the arterial wall. Yet, the current methods for their assessment are unsuitable for routine use. Post-exercise response of the cardiovascular (CV) system serves as a more sensitive detection of subclinical arterial abnormalities that are not apparent at-rest. The objective of this study is to propose a novel method that can measure post-exercise response of arterial parameters and is also suitable for routine use.

APPROACH

A microfluidic tactile sensor with a location-insensitive configuration was used for arterial pulse signal measurements on six asymptomatic male subjects, offering measurement reliability, ease use by a layperson, and affordability. By treating the arterial pulse signal as a vibration signal of the arterial wall, vibration-model-based analysis of only one measured pulse signal with no calibration was conducted for simultaneous estimation of three arterial parameters. Exercise-intensity-normalized percent changes in arterial parameters were utilized to remove the influence of variation in exercise intensity on post-exercise response, and then their measured values were compared for difference in post-exercise response between the subjects.

MAIN RESULTS

One subject who was obese, on subject who had insomnia, and the oldest subject in the study demonstrated differences in post-exercise response at the radial artery (RA), as compared with the three subjects free of those three factors. Despite a lack of statistical significance, the observed difference at the RA between subjects was supported by (i) their consistency with the related findings in the literature, and (ii) their consistency with the measured values at the carotid artery (CA) and superficial temporal artery (STA) and the anatomical difference between the three arteries.

SIGNIFICANCE

The proposed method has the potential of offering an affordable and convenient diagnosis tool for routine arterial health assessment.

Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology

The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.

Crucial role for Nox2 and sleep deprivation in aircraft noise-induced vascular and cerebral oxidative stress, inflammation, and gene regulation

Aims

Aircraft noise causes endothelial dysfunction, oxidative stress, and inflammation. Transportation noise increases the incidence of coronary artery disease, hypertension, and stroke. The underlying mechanisms are not well understood. Herein, we investigated effects of phagocyte-type NADPH oxidase (Nox2) knockout and different noise protocols (around-the-clock, sleep/awake phase noise) on vascular and cerebral complications in mice.

Methods and results

C57BL/6j and Nox2^−/− (gp91phox^−/−) mice were exposed to aircraft noise (maximum sound level of 85 dB(A), average sound pressure level of 72 dB(A)) around-the-clock or during sleep/awake phases for 1, 2, and 4 days. Adverse effects of around-the-clock noise on the vasculature and brain were mostly prevented by Nox2 deficiency. Around-the-clock aircraft noise of the mice caused the most pronounced vascular effects and dysregulation of Foxo3/circadian clock as revealed by next generation sequencing (NGS), suggesting impaired sleep quality in exposed mice. Accordingly, sleep but not awake phase noise caused increased blood pressure, endothelial dysfunction, increased markers of vascular/systemic oxidative stress, and inflammation. Noise also caused cerebral oxidative stress and inflammation, endothelial and neuronal nitric oxide synthase (e/nNOS) uncoupling, nNOS mRNA and protein down-regulation, and Nox2 activation. NGS revealed similarities in adverse gene regulation between around-the-clock and sleep phase noise. In patients with established coronary artery disease, night-time aircraft noise increased oxidative stress, and inflammation biomarkers in serum.

Conclusion

Aircraft noise increases vascular and cerebral oxidative stress via Nox2. Sleep deprivation and/or fragmentation caused by noise triggers vascular dysfunction. Thus, preventive measures that reduce night-time aircraft noise are warranted.

Impaired endothelial function may predict treatment response in restless legs syndrome

While dopaminergic dysfunction is believed to be a crucial role in restless legs syndrome (RLS), changes in peripheral microvasculature system such as peripheral hypoxia and altered skin temperature, have been found. This study aimed to investigate whether patients with RLS would have a cerebral and peripheral endothelial dysfunction, and this may have association with treatment responsiveness. We evaluated cerebral endothelial function using breath-holding index (BHI) on transcranial Doppler in bilateral middle cerebral artery (MCA), posterior cerebral artery (PCA) and basilar artery (BA) and peripheral endothelial function using brachial flow-mediated dilation (FMD) in 34 patients with RLS compared with age and sex-matched controls. The values of BHI in both MCA and BA were significantly lower in RLS group than control group. The values of FMD also were significantly lower in RLS patients. There was a weak correlation between BHI and FMD (p = 0.038 in Rt MCA, p = 0.032 in Lt MCA, p = 0.362 in BA) in RLS, but not in controls. BHI differed according to treatment responsiveness. (p < 0.005). Our study suggests that RLS patients have poorer cerebral and peripheral endothelial function than controls, showing an underlying mechanism of RLS and further evidence of a possible association between RLS and cardiovascular disease.

Sleep Deprivation and Chronic Health Conditions Among Sexual Minority Adults

OBJECTIVES

To examine associations between sleep duration and health outcomes among distinct groups of sexual minority adults.

METHODS

Using data from the 2014 Behavioral Risk Factor Surveillance System, we compared sleep duration (very short: ≤ 5 hr; short: 6 hr; normal: 7-8 hr; and long: ≥ 9 hr per day) between cisgender straight adults and distinct groups of sexual minorities. We further examined associations between sleep duration and 10 chronic health conditions among sexual minorities.

RESULTS

Of 146,893 respondents, 142,507 (96.2%) were cisgender straight, and 4,386 (3.8%) were lesbian, gay, bisexual, transgender (LGBT). Overall, 17.3% of LGBT respondents reported very short sleep per day, compared with 12.2% for cisgender straight respondents (p < 0.0001). Among LGBT populations, the prevalence of very short sleep varied significantly among distinct groups, ranging from 13.2% among transgender female to male adults to 35.5% among transgender gender nonconforming adults. Very short sleep was further associated with increased odds of having stroke (aOR = 4.1, 95% CI [2.2-7.6]), heart attack (aOR = 3.0, CI [1.6-5.8]), coronary heart disease (aOR = 3.1, 95% CI [1.5-6.2]), asthma (aOR = 1.7, 95% CI [1.1-2.4]), chronic obstructive pulmonary disease (aOR = 2.5, CI [1.5-4.0]), arthritis (aOR = 2.1, CI [1.4-3.0]), and cancer (aOR = 1.8, 95% CI [1.0-3.2]) among sexual minorities. Disparities in the prevalence of stroke, heart attack, coronary health disease, COPD, diabetes, obesity, arthritis, and cancer were found among LGBT populations.

CONCLUSIONS

Sexual minorities have a higher prevalence of sleep deprivation as compared with their straight counterparts. Sleep deprivation varies by sexual identity and gender. Very short sleep duration is associated with some chronic health conditions among LGBT populations. Promotion of sleep health education and routine medical assessment of sleep disorders are critically needed for sexual minority adults.

Insufficient sleep is associated with a pro-atherogenic circulating microRNA signature

NEW FINDINGS

What is the central question of the study Is habitual short sleep associated with altered circulating levels of specific inflammation- and vascular-related microRNAs? What is the main finding and its importance? Circulating levels of miR-125a, miR-126 and miR-146a were significantly lower in the short sleep compared with the normal sleep group. Altered circulating profiles of these vascular-related microRNAs have been linked to vascular inflammation, dysfunction and increased cardiovascular disease events. Sleep-related changes in these microRNAs are consistent with, and might play a role in, the aberrant vascular physiology and increased vascular risk associated with short sleep.

ABSTRACT

Habitual short sleep duration (<7 h night^-1 ) is associated with increased morbidity and mortality attributable, in large part, to increased inflammatory burden and endothelial dysfunction. MicroRNAs (miRNAs) play a key role in regulating vascular health, and circulating levels are now recognized to be sensitive and specific biomarkers of cardiovascular function, inflammation and disease.  The aim of this study was to determine whether the expression of circulating miR-34a, miR-92a, miR-125a, miR-126, miR-145, miR-146a and miR-150 is disrupted in adults who habitually sleep <7 h night^-1 (short sleep). These were chosen based upon their well-established links with vascular inflammation, function and, in turn, cardiovascular risk. Twenty-four adults were studied: 12 with normal nightly sleep duration (six men and six women; age, 55 ± 3 years old; sleep duration, ≥7.0 h night^-1 ) and 12 with short nightly sleep duration (seven men and five women; 55 ± 2 years old; sleep duration, <7 h night^-1 ), and circulating miRNA expression was assayed by RT-PCR. All subjects were non-smokers, normolipidaemic, non-medicated and free of overt cardiovascular disease. Circulating levels of miR-125a (3.07 ± 1.98 versus 7.34 ± 5.34 a.u.), miR-126 [1.28 (0.42-2.51) versus 1.78 (1.29-4.80) a.u.] and miR-146a [2.55 (1.00-4.80) versus 6.46 (1.50-11.44) a.u.] were significantly lower (∼60, 40 and 60%, respectively) in the short compared with the normal sleep group. However, there were no significant group differences in circulating levels of miR-34a, miR-92a, miR-145 and miR-150. In summary, chronic short sleep is associated with a marked reduction in circulating levels of miR-125a, miR-126 and miR-146a. Dysregulation of these miRNAs might contribute to the increased inflammatory burden and endothelial dysfunction associated with habitual insufficient sleep.

Experimental sleep restriction effect on adult body weight: a meta-analysis

BACKGROUND

Sleep is increasingly recognized as a potential risk for overweight and obesity. Observational studies have shown links between short sleep duration with weight gain. However, the findings from longitudinal studies in adults are conflicting. This review aimed to examine the effectiveness of experimental sleep restriction on adult body weight.

METHOD

A systematic search was undertaken in MEDLINE, EMBASE, PsycINFO, and CENTRAL (Cochrane center register of controlled trials) to identify experimental studies examining the effectiveness of sleep restriction on body weight, and search period was from January 2005 to June 2018. Meta-analysis was applied by using the random model.

RESULTS

A total of 275 adults from six experimental studies were included. The pooled standard mean difference in body weight and body fat was 0.44 (95% CI - 0.13 to 1.02) (Z = 1.51, p > 0.05) and 0.35 kg (95% CI - 0.19 to 0.88) (Z = 1.27, p > 0.05), respectively. The experimental sleep restriction did not result in significant differences in adult body weight or body fat. Subgroup analysis showed that there were differences in weight gain between genders and races.

CONCLUSION

The finding from this review cannot support the hypothesis from observational studies that short sleep leads to weight gain.

Sleep, Autonomic Nervous Function and Atherosclerosis

Behavioral and psychosocial factors related to development of cardiovascular disease have been gaining increased attention. Notably, sleep is considered to be one of the most important behavioral factors involved in progression of atherosclerosis and cardiovascular events, with autonomic nervous function a potential mechanism. Several studies have shown associations of sleep and autonomic dysfunction with major surrogate markers of atherosclerosis, such as carotid intima-media thickness and arterial stiffness. Endocrinological, immunological, oxidative, inflammatory, and metabolic responses, as well as endothelial dysfunction may mediate the effects of the autonomic nervous system. For this review, we examined recent findings related to sleep, autonomic nervous dysfunction, and atherosclerosis, with the aim of understanding the involved pathophysiological mechanisms.

Obstructive sleep apnoea and comorbidity - an overview of the association and impact of continuous positive airway pressure therapy

INTRODUCTION

Obstructive sleep apnoea (OSA) is highly prevalent and there is considerable evidence supporting an independent association with a wide range of co-morbidities including cardiovascular, endocrine and metabolic, neuropsychiatric, pulmonary, and renal. Areas covered: A PubMed search of all the recent literature relating to OSA and co-morbidities was undertaken to critically evaluate the potential relationships and possible benefit of continuous positive airway pressure (CPAP) therapy. Expert commentary: The evidence supporting an independent association is stronger for some co-morbidities than others and in cardiovascular diseases is strongest for hypertension and atrial fibrillation. Potential mechanisms include intermittent hypoxia, fluctuating intrathoracic pressure, and recurring micro-arousals that trigger cell and molecular consequences including sympathetic excitation, systemic inflammation and oxidative stress, in addition to metabolic and endothelial dysfunction. Different mechanisms may predominate in individual co-morbidities. Recent long term randomised controlled trials have cast doubt on benefits to co-morbidities from CPAP therapy of OSA, especially where co-morbidities are already established. However, benefits may result in patients who are compliant with therapy and further research is required to clearly establish the role of OSA therapy in both primary and secondary prevention of co-morbidities.

Roles of sleep deprivation in cardiovascular dysfunctions

It is widely recognized that inadequate sleep is associated with multiple acute and chronic diseases and results in increased mortality and morbidity for cardiovascular diseases. In recent years, there has been increasing interest in sleep related investigations. Emerging evidence indicates that sleep deprivation changes the biological phenotypes of DNA, RNA and protein levels, but the underlying mechanisms are not clear. We summarized the current research on the detrimental roles of sleep deprivation on the heart and elucidated the underlying mechanisms of sleep deficiency to improve our understanding of sleep deprivation and the emerging strategies to target this process for therapeutic benefit.