Effect of acute sleep deprivation on heart rate recovery in healthy young adults

Joint association of sedentary time and physical activity with abnormal heart rate recovery in young and middle-aged adults

BACKGROUND

Abnormal heart rate recovery (HRR), representing cardiac autonomic dysfunction, is an important predictor of cardiovascular disease. Prolonged sedentary time (ST) is associated with a slower HRR. However, it is not clear how much moderate-to-vigorous physical activity (MVPA) is required to mitigate the adverse effects of sedentary behavior on HRR in young and middle-aged adults. This study aimed to examine the joint association of ST and MVPA with abnormal HRR in this population.

METHODS

A cross-sectional analysis was conducted on 1253 participants (aged 20-50 years, 67.8% male) from an observational study assessing cardiopulmonary fitness in Fujian Province, China. HRR measured via cardiopulmonary exercise tests on a treadmill was calculated as the difference between heart rate at peak exercise and 2 min after exercise. When the HRR was ≤ 42 beats·minute-1 within this time, it was considered abnormal. ST and MVPA were assessed by the IPAQ-LF. Individuals were classified as having a low sedentary time (LST [< 6 h·day-1]) or high sedentary time (HST [≥ 6 h·day-1]) and according to their MVPA level (low MVPA [0-149 min·week-1], medium MVPA [150-299 min·week-1], high MVPA [≥ 300 min·week-1]). Finally, six ST-MVPA groups were derived. Associations between ST-MVPA groups with abnormal HRR incidence were examined using logistic regression models.

RESULTS

53.1% of the young and middle-aged adults had less than 300 min of MVPA per week. In model 2, adjusted for possible confounders (e.g. age, sex, current smoking status, current alcohol consumption, sleep status, body mass index), HST was associated with higher odds of an abnormal HRR compared to LST (odds ratio (OR) = 1.473, 95% confidence interval (CI) = 1.172-1.852). Compared with the reference group (HST and low MVPA), the HST and high MVPA groups have a lower chance of abnormal HRR (OR, 95% CI = 0.553, 0.385-0.795). Compared with individuals with HST and low MVPA, regardless of whether MVPA is low, medium, or high, the odds of abnormal HRR in individuals with LST is significantly reduced (OR, 95% CI = 0.515, 0.308-0.857 for LST and low MVPA; OR, 95% CI = 0.558, 0.345-0.902 for LST and medium MVPA; OR, 95% CI = 0.476, 0.326-0.668 for LST and high MVPA).

CONCLUSION

Higher amounts of MVPA appears to mitigate the increased odds of an abnormal HRR associated with HST for healthy young and middle-aged adults.

Chronic sleep fragmentation reduces left ventricular contractile function and alters gene expression related to innate immune response and circadian rhythm in the mouse heart

Sleep disorders have emerged as a widespread public health concern, primarily due to their association with an increased risk of developing cardiovascular diseases. Our previous research indicated a potential direct impact of insufficient sleep duration on cardiac remodeling in children and adolescents. Nevertheless, the underlying mechanisms behind the link between sleep fragmentation (SF) and cardiac abnormalities remain unclear. In this study, we aimed to investigate the effects of SF interventions at various life stages on cardiac structure and function, as well as to identify genes associated with SF-induced cardiac dysfunction. To achieve this, we established mouse models of chronic SF and two-week sleep recovery (SR). Our results revealed that chronic SF significantly compromised left ventricular contractile function across different life stages, leading to alterations in cardiac structure and ventricular remodeling, particularly during early life stages. Moreover, microarray analysis of mouse heart tissue identified two significant modules and nine hub genes (Ddx60, Irf9, Oasl2, Rnf213, Cmpk2, Stat2, Parp14, Gbp3, and Herc6) through protein-protein interaction analysis. Notably, the interactome predominantly involved innate immune responses. Importantly, all hub genes lost significance following SR. The second module primarily consisted of circadian clock genes, and real-time PCR validation demonstrated significant upregulation of Arntl, Dbp, and Cry1 after SF, while subsequent SR restored normal Arntl expression. Furthermore, the expression levels of four hub genes (Ddx60, Irf9, Oasl2, and Cmpk2) and three circadian clock genes (Arntl, Dbp, and Cry1) exhibited correlations with structural and functional echocardiographic parameters. Overall, our findings suggest that SF impairs left ventricular contractile function and ventricular remodeling during early life stages, and this may be mediated by modulation of the innate immune response and circadian rhythm. Importantly, our findings suggest that a short period of SR can alleviate the detrimental effects of SF on the cardiac immune response, while the influence of SF on circadian rhythm appears to be more persistent. These findings underscore the importance of good sleep for maintaining cardiac health, particularly during early life stages.

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.

Acute sleep deprivation: impairment of biventricular function assesed by speckle tracking echocardiography in healthy subjects

OBJECTIVES

Sleep deprivation (SD) has been found to be associated with an increased incidence of adverse cardiovascular disease (CVD) events. The aim of this study was to investigate whether or not acute SD has a pathological effect on the geometry and the systolic and diastolic functions of the right and left heart chambers by standard transthoracic echocardiography (TTE) and speckle tracking echocardiography (STE) in healthy individuals with acute SD.

METHODS

Nurses with no history of acute or chronic diseases underwent TTE and STE after working a night shift, a sleepless period of 24 h and 7 days of normal sleep after the night shift. Measurements of TTE and STE taken in the rested state were compared with those taken after 24 h of sleep deprivation.

RESULTS

The study included 52 nurses (38 women, 73%). The mean age of the study population was 27.9 ± 7.4 years and mean BMI was 24.1 ± 4.8. Left atrial reservoir (51.5 ± 13.5 vs. 45.4 ± 10; p = 0.004), conduit (- 37.3 ± 11.3 vs. - 33.6 ± 7.9; p = 0.01), left ventricular global longitudinal strain (LVGLS, - 22.6 ± 2.4 vs. - 21.3 ± 2.4; p = 0.001), right ventricular global longitudinal strain (RVGLS, - 25.3 ± 3.7 vs. - 23.5 ± 3.9; p = 0.005) and right ventricular free wall longitudinal strain (RVFWSL, - 29.1 ± 4.2 vs. - 27 ± 4.5; p = 0.001) were impaired significantly after SD.

CONCLUSION

This study is the first to investigate the negative effects of acute sleep deprivation on LV and RV strain in healthy adults using echocardiography. The findings showed that acute sleep deprivation leads to deterioration in function of both ventricles and left atrium. Speckle tracking echocardiography demonstrated subclinical diminished heart function.

Sleep Deprivation and Heart Rate Variability in Healthy Volunteers: Effects of REM and SWS Sleep Deprivation

Objective

Using PSG-guided acute selective REM/SWS sleep deprivation in volunteers, this study examined the effects of sleep deprivation on the cardiovascular and autonomic nervous systems, as well as the relationship between cardiac neuromodulation homeostasis and cardiovascular disease.

Methods

An experiment was conducted using 30 healthy volunteers (male : female = 1 : 1, aged 26.33 ± 4.5 years) divided into groups for sleep deprivation of SWS and REM sleep, and then, each group was crossed over for normal sleep (2 days) and repeated sleep deprivation (1 day, 3 times). During the study period, PSG and ELECTRO ECG monitoring were conducted, and five-minute frequency domain parameters and blood pressure values were measured before and after sleep deprivation.

Results

Changes in VLF, LFnu, LF/HF, HF, and HFnu after SWS sleep deprivation were statistically significant (P < 0.05), but not LF (P = 0.063). Changes in VLF, LF, HF, LF/HF, LFnu, and HFnu after REM sleep deprivation were not statistically significant (P > 0.05).

Conclusions

An increase in sympathetic nerve activity results from sleep deprivation and sudden awakening from SWS sleep is associated with a greater risk of cardiovascular disease.

Long-Term Sleep Deprivation-Induced Myocardial Remodeling and Mitochondrial Dysfunction in Mice Were Attenuated by Lipoic Acid and N-Acetylcysteine

The impact of long-term sleep deprivation on the heart and its underlying mechanisms are poorly understood. The present study aimed to investigate the impact of chronic sleep deprivation (CSD) on the heart and mitochondrial function and explore an effective drug for treating CSD-induced heart dysfunction. We used a modified method to induce CSD in mice; lipoic acid (LA) and N-acetylcysteine (NAC) were used to treat CSD mice. Echocardiography, hematoxylin-eosin (H&E) staining, Sirius red staining, and immunohistochemistry were used to determine heart function and cardiac fibrosis. The serum levels of brain natriuretic peptide (BNP), superoxide Dismutase (SOD), micro malondialdehyde (MDA), and glutathione (GSH) were measured to determine cardiovascular and oxidative stress-related damage. Transmission electron microscopy was used to investigate mitochondrial damage. RNA-seq and Western blotting were used to explore related pathways. We found that the left ventricular ejection fraction (LVEF) and fraction shortening (LVFS) values were significantly decreased and myocardial hypertrophy was induced, accompanied by damaged mitochondria, elevated reactive oxygen species (ROS), and reduced SOD levels. RNA-sequence analysis of the heart tissue showed that various differentially expressed genes in the metabolic pathway were enriched. Sirtuin 1 (Sirt1) and Glutathione S-transferase A3 (Gsta3) may be responsible for CSD-induced heart and mitochondrial dysfunction. Pharmacological inhibition of ROS by treating CSD mice with LA and NAC effectively reduced heart damage and mitochondrial dysfunction by regulating Sirt1 and Gsta3 expression. Our data contribute to understanding the pathways of CSD-induced heart dysfunction, and pharmacological targeting to ROS may represent a strategy to prevent CSD-induced heart damage.

Sleep duration and disturbance are associated with orthostatic heart rate recovery: Findings from the Irish Longitudinal Study on Ageing

OBJECTIVE

To examine a novel measurement of autonomic innervation, the early heart rate response to orthostasis, in relation to sleep duration and disturbance (actigraphy-based and self-reported) in healthy older adults.

DESIGN

Cross-sectional analyses of a nationally representative prospective cohort study, the Irish Longitudinal Study on Ageing (TILDA).

PARTICIPANTS

Nine hundred sixty community-dwelling adults aged 50 and over (mean age 65.6 ± 8.1; 53% women).

MEASUREMENT

Orthostatic heart rate response was measured during an active stand test. Beat-to-beat heart rate was monitored over 3 minutes using noninvasive digital photoplethysmography. Mean values at each 10-second time point after standing were generated and differences from baseline at each time point were used for analysis. Actigraphy-based sleep measures were extracted from wrist-worn GENEactiv devices; self-reported sleep measures using interview questions.

RESULTS

Linear mixed-effects regression analyses, with inclusion of a large number of confounders, show that self-reported sleep duration and actigraphy-based sleep duration and disturbance were associated with altered orthostatic heart rate response, particularly within the first 20 seconds poststanding. Self-reported short sleep (β = -0.06; 95% confidence interval [CI]: -0.11, -0.01) and long sleep (β = -0.15; 95% CI: -0.24, -0.05) and actigraphy-based short sleep (β = -0.08; 95% CI: -0.14, -0.01) were characterized by a smaller increase at 10 seconds (p < .01). Actigraphy-based short sleep (β = 0.15; 95% CI: 0.08, 0.22) and sleep disturbance (β = 0.04; 95% CI: 0.02, 0.06) were associated with a slower return toward baseline at 20 seconds (p < .001).

CONCLUSIONS

Our findings suggest sympathetic dysregulation, impaired vagal reactivation, and/or decreased baroreceptor sensitivity in the presence of shortened or disturbed sleep.

Effect of selective sleep deprivation on heart rate variability in post-90s healthy volunteers

The 5-minute frequency domain method was used to examine the effects of polysomnography (PSG)-guided acute selective sleep deprivation (REM/SWS) on the cardiovascular autonomic nervous system, heart rate, and rhythm in healthy volunteers to understand the relationship between cardiac neuro regulatory homeostasis and cardiovascular system diseases in healthy subjects. The study included 30 healthy volunteers selected through the randomized-controlled method, randomly divided into REM sleep deprivation and SWS sleep deprivation groups. PSG analyses and dynamic electrocardiogram monitoring were done at night, during slow wave sleep or REM sleep. An all-night sleep paradigm, without any interruptions, was tested 3 times for comparison. The frequency domain parameter method was further used to monitor the volunteers 5 min before and after a period of sleep deprivation. According to the characteristics of the all-night sleep scatter plot, healthy volunteers were divided into abnormal and normal scatter plot groups. When compared with the period before sleep deprivation, high frequency (HF) and normalized high-frequency component (HFnu) were found to be decreased. Normalized low-frequency component (LFnu) increased in the abnormal scatter plot group after sleep deprivation, and this difference was statistically significant (P < 0.05). The scatter plot also showed that very low frequency (VLF) increased only in the normal group after deprivation and this difference, as well, was statistically significant (P < 0.05). The increase in diastolic blood pressure in the abnormal group was statistically significant (P < 0.05), but the change in blood pressure in the normal group was not statistically significant (P > 0.05). There are 62.5% of the patients and 20% of the employees that were observed to have abnormal whole-night sleep patterns during the uninterrupted whole-night sleep regime. Patients with atrial or ventricular premature beats (more than 0.1%), and those with ST-t changes during sleep, were all ascertained as abnormal. We concluded that some healthy people could face unstable autonomic nervous functioning related to their long-term tension, anxiety, time urgency, hostility, and other chronic stress states. In the face of acute sleep deprivation selectivity, mild stress based excitability of the vagus nerve is reduced, which diminishes the protective function, making them susceptible to conditions such as premature ventricular arrhythmia.

Observational and Genetic Associations of Modifiable Risk Factors with Aortic Valve Stenosis: A Prospective Cohort Study of 0.5 Million Participants

Background: Observational studies have shown that modifiable risk factors are associated with aortic valve stenosis (AVS). However, the causality behind these associations remains largely unknown. Objectives: To explore the associations of modifiable risk factors, including metabolic factors, biochemical measures, education, and lifestyles with AVS and their potential causal associations. Methods: We enrolled 361,930 British white people with genetic data in the UK biobank. Cox proportional risk regression models were used to estimate the hazard ratios between 28 modifiable risk factors and AVS. We used genetic instruments for modifiable risk factors to determine the potential causal relationships using a one-sample Mendelian randomization (MR) approach. Results: A total of 1602 participants developed AVS during an 8.4-year follow-up. Observational analyses showed higher adiposity, blood pressure, heart rate, low-density lipoprotein, urate, C-reactive protein, creatinine, albumin, and glycated hemoglobin, but lower serum vitamin D, and education, unhealthy lifestyle, and poor sleep quality were related to a higher risk of AVS after adjusting for the Bonferroni correction (p < 0.0013). Genetically predicted 1-SD higher levels of body mass index [HR: 1.09, 95% CI: 1.03 to 1.16], body fat percentage (1.17, 1.03 to 1.33), triglyceride (TG) [1.08, 1.00 to 1.16], low-density lipoprotein (LDL) (1.15, 1.08 to 1.21) and serum total cholesterol (TC) (1.13, 1.02 to 1.25) were associated with a higher risk of AVS, respectively. Genetically determined per category higher insomnia (1.32, 1.13 to 1.55) was also associated with AVS. The abovementioned genetic associations with the incident AVS showed an increasing relationship pattern. Conclusions: This study provides strong evidence for the potential causal roles of cardiometabolic factors in developing AVS, highlighting that an idea of metabolic status through a healthy lifestyle may help prevent AVS.

Not so sweet dreams: adults' quantity, quality, and disruptions of sleep during the initial stages of the COVID-19 pandemic

OBJECTIVES

The purpose of this study was to investigate Ontario adults' reported sleep quantity, quality, and disturbances during the early months of the COVID-19 pandemic (April-July 2020).

METHODS

As part of a larger, chronic disease-focused, and ongoing longitudinal study designed to explore Ontario adults' health and wellness-related behaviors during the pandemic, participants completed an online survey that included demographic information and the Pittsburgh Sleep Quality Index (PSQI). The PSQI consists of 19 items, one of which is open-ended, designed to assess an individual's quantity, quality, and patterns of sleep on seven domains (ie, subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleep medication, and daytime dysfunction over the last month). Summative content analysis was used to analyze responses to the open-ended question regarding participants' sleep disturbances.

RESULTS

This study included 2192 individuals, 85% of whom slept 6+ hours/night. The mean global PSQI score was 7.57, out of a possible 21 (SD = 4.09). The self-reported sleep disturbances of largest concern were: (1) general fear/anxiety/worry (n = 203); (2) children (n = 167); (3) mind wandering/overthinking (n = 118); (4) pain/injury (n = 78); (5) partner (n = 78); and (6) fear/anxiety/stress related to COVID-19 (n = 74).

CONCLUSION

The global PSQI score was indicative of poor sleep quality, and Ontario adults experienced a number of sleep disturbances during early days of the COVID-19 pandemic. These findings are noteworthy as sleep is a crucial component in positive health and wellbeing.

Causal Roles of Sleep Duration in Osteoporosis and Cardiometabolic Diseases: A Mendelian Randomization Study

Sleep duration suggests some association with osteoporosis and cardiometabolic diseases, but it is unknown if these associations are causal or confounded. In this two-sample Mendelian randomization (MR) study, we included the largest genome-wide association studies (GWASs) associated with sleep duration and the outcome measures of osteoporosis and cardiometabolic diseases. Finally, 25 single nucleotide polymorphisms (SNPs) associated with short sleep duration and 7 SNPs associated with long sleep duration obtained the genome-wide significance (P < 5 × 10^-8) and were used as instrumental variables. Genetic predisposition to short sleep duration was strongly associated with increased risk of coronary artery disease (beta-estimate: 0.199, 95% confidence interval CI: 0.081 to 0.317, standard error SE:0.060, P value = 0.001) and heart failure (beta-estimate: 0.145, 95% CI: 0.025 to 0.264, SE:0.061, P value = 0.017), which were both confirmed by the sensitivity analyses. Both short and long sleep duration may reduce the estimated bone mineral density (eBMD, beta-estimate: -0.086, 95% CI: -0.141 to -0.031, SE:0.028, P value = 0.002 for short sleep duration; beta-estimate: -0.080, 95% CI: -0.120 to -0.041, SE:0.020, P value < 0.0001 for long sleep duration). There was limited evidence of associations between sleep duration and fracture, type 2 diabetes, atrial fibrillation, fasting glucose, fasting insulin, or HbA1c. This study provides robust evidence that short sleep duration is causally associated with high risk of coronary artery disease and heart failure and suggests that short sleep duration should be avoided to prevent these two cardiovascular diseases. Short and long sleep duration show some MR association with reduced eBMD, which indicates that both short and long sleep duration may be prevented to reduce the incidence of osteoporosis.

Job burnout and its impact on work ability in biosafety laboratory staff during the COVID-19 epidemic in Xinjiang

BACKGROUND

The coronavirus disease 2019 (COVID-19) has increased the physical and psychological stress of medical workers. This study was designed to investigate the prevalence and risk factors of job burnout and its impact on work ability among Biosafety Laboratory (BSL) staffs during the COVID-19 epidemic in Xinjiang.

METHODS

A total of 7911 qualified BSL staffs in Xinjiang were investigated by electronic questionnaires. The Maslach Burnout Inventory-General Survey (MBI-GS) was used for job burnout survey. Work Ability Index (WAI) was used for work ability survey. The prevalence and risk factors of job burnout in BSL staffs were analyzed through chi square test, t-test and one-way ANOVA. And then, the influence of demographic and job-related variables, i.e., confounding factors, were eliminated to the greatest extent by the propensity score analysis (PSA) method, to investigate the impact of job burnout on work ability in BSL staffs.

RESULTS

A total of 67.6% BSL staffs experienced job burnout. There were significant differences in the detection rate of job burnout among demographic and job-related variables, including gender, age, ethnicity, education, working years, professional title, marital status, number of night shift per month and overall sleep condition (all P < 0.05). The detection rate of job burnout in female was higher than that in male. The detection rates of job burnout in 45-50 years old, Han ethnicity, education of postgraduate or above, 11-20 years of working, intermediate professional title, married, staff with many night shifts per month and poor overall sleep condition were higher than that of other groups. The average burnout scores of the Emotional Exhaustion (EE), Cynicism (CY), Reduced Personal Accomplishment (PA) scale were 10.00 ± 5.99, 4.64 ± 4.59 and 15.25 ± 8.16, respectively. Multiple logistic regression analysis showed that the three dimensions of job burnout, i.e., EE, CY, PE, were negatively correlated with work ability and significantly affected the work ability of BSL staffs (all P < 0.001).

CONCLUSIONS

Our results suggest that the prevalence of job burnout is extremely common among BSL staffs. In addition, the work ability decreases with the increase of job burnout and the improvement of job burnout can enhance work ability among BSL staffs.

Sleep deprivation reduces vagal tone during an inspiratory endurance task in humans

STUDY OBJECTIVES

Sleep deprivation alters inspiratory endurance by reducing inspiratory motor output. Vagal tone is involved in exercise endurance. This study aimed to investigate the effect of sleep deprivation on vagal tone adaptation in healthy subjects performing an inspiratory effort.

METHODS

Vagal tone was assessed using Heart Rate Variability normalized units of frequency domain component HF (high frequency) before, at the start, and the end of an inspiratory loading trial performed until exhaustion by 16 volunteers after one night of sleep deprivation and one night of normal sleep, where sleep deprivation reduced the inspiratory endurance by half compared to the normal sleep condition (30 min vs 60 min).

RESULTS

At rest, heart rate was similar in sleep deprivation and normal sleep conditions. In normal sleep condition, heart rate increased during inspiratory loading task; this increase was greater in sleep deprivation condition. In normal sleep condition, vagal tone increased at the beginning of the trial. This vagal tone increase was absent in sleep deprivation condition.

CONCLUSIONS

Sleep deprivation abolished vagal tone response to inspiratory load, possibly contributing to a higher heart rate during the trial and to a reduced inspiratory endurance.

CLINICAL TRIAL REGISTRATION

NCT02725190.

A machine learning model for multi-night actigraphic detection of chronic insomnia: development and validation of a pre-screening tool

We propose a novel machine learning-based method for analysing multi-night actigraphy signals to objectively classify and differentiate nocturnal awakenings in individuals with chronic insomnia (CI) and their cohabiting healthy partners. We analysed nocturnal actigraphy signals from 40 cohabiting couples with one partner seeking treatment for insomnia. We extracted 12 time-domain dynamic and nonlinear features from the actigraphy signals to classify nocturnal awakenings in healthy individuals and those with CI. These features were then used to train two machine learning classifiers, random forest (RF) and support vector machine (SVM). An optimization algorithm that incorporated the predicted quality of each night for each individual was used to classify individuals into CI or healthy sleepers. Using the proposed actigraphic signal analysis technique, coupled with a rigorous leave-one-out validation approach, we achieved a classification accuracy of 80% (sensitivity: 76%, specificity: 82%) in classifying CI individuals and their healthy bed partners. The RF classifier (accuracy: 80%) showed a better performance than SVM (accuracy: 75%). Our approach to analysing the multi-night nocturnal actigraphy recordings provides a new method for screening individuals with CI, using wrist-actigraphy devices, facilitating home monitoring.

Causal associations of short and long sleep durations with 12 cardiovascular diseases: linear and nonlinear Mendelian randomization analyses in UK Biobank

AIMS

Observational studies have suggested strong associations between sleep duration and many cardiovascular diseases (CVDs), but causal inferences have not been confirmed. We aimed to determine the causal associations between genetically predicted sleep duration and 12 CVDs using both linear and nonlinear Mendelian randomization (MR) designs.

METHODS AND RESULTS

Genetic variants associated with continuous, short (≤6 h) and long (≥9 h) sleep durations were used to examine the causal associations with 12 CVDs among 404 044 UK Biobank participants of White British ancestry. Linear MR analyses showed that genetically predicted sleep duration was negatively associated with arterial hypertension, atrial fibrillation, pulmonary embolism, and chronic ischaemic heart disease after correcting for multiple tests (P < 0.001). Nonlinear MR analyses demonstrated nonlinearity (L-shaped associations) between genetically predicted sleep duration and four CVDs, including arterial hypertension, chronic ischaemic heart disease, coronary artery disease, and myocardial infarction. Complementary analyses provided confirmative evidence of the adverse effects of genetically predicted short sleep duration on the risks of 5 out of the 12 CVDs, including arterial hypertension, pulmonary embolism, coronary artery disease, myocardial infarction, and chronic ischaemic heart disease (P < 0.001), and suggestive evidence for atrial fibrillation (P < 0.05). However, genetically predicted long sleep duration was not associated with any CVD.

CONCLUSION

This study suggests that genetically predicted short sleep duration is a potential causal risk factor of several CVDs, while genetically predicted long sleep duration is unlikely to be a causal risk factor for most CVDs.

Evaluations of Commercial Sleep Technologies for Objective Monitoring During Routine Sleeping Conditions

PURPOSE

The commercial market is saturated with technologies that claim to collect proficient, free-living sleep measurements despite a severe lack of independent third-party evaluations. Therefore, the present study evaluated the accuracy of various commercial sleep technologies during in-home sleeping conditions.

MATERIALS AND METHODS

Data collection spanned 98 separate nights of ad libitum sleep from five healthy adults. Prior to bedtime, participants utilized nine popular sleep devices while concurrently wearing a previously validated electroencephalography (EEG)-based device. Data collected from the commercial devices were extracted for later comparison against EEG to determine degrees of accuracy. Sleep and wake summary outcomes as well as sleep staging metrics were evaluated, where available, for each device.

RESULTS

Total sleep time (TST), total wake time (TWT), and sleep efficiency (SE) were measured with greater accuracy (lower percent errors) and limited bias by Fitbit Ionic [mean absolute percent error, bias (95% confidence interval); TST: 9.90%, 0.25 (-0.11, 0.61); TWT: 25.64%, -0.17 (-0.28, -0.06); SE: 3.49%, 0.65 (-0.82, 2.12)] and Oura smart ring [TST: 7.39%, 0.19 (0.04, 0.35); TWT: 36.29%, -0.18 (-0.31, -0.04); SE: 5.42%, 1.66 (0.17, 3.15)], whereas all other devices demonstrated a propensity to over or underestimate at least one if not all of the aforementioned sleep metrics. No commercial sleep technology appeared to accurately quantify sleep stages.

CONCLUSION

Generally speaking, commercial sleep technologies displayed lower error and bias values when quantifying sleep/wake states as compared to sleep staging durations. Still, these findings revealed that there is a remarkably high degree of variability in the accuracy of commercial sleep technologies, which further emphasizes that continuous evaluations of newly developed sleep technologies are vital. End-users may then be able to determine more accurately which sleep device is most suited for their desired application(s).

Sleep deprivation and its association with diseases- a review

Sleep deprivation, a consequence of multiple health problems or a cause of many major health risks, is a significant public health concern in this era. In the recent years, numerous reports have been added to the literature to provide explanation and to answer previously unanswered questions on this important topic but comprehensive updates and reviews in this aspect remain scarce. The present study identified 135 papers that investigated the association between sleep deprivation and health risks, including cardiovascular, respiratory, neurological, gastrointestinal, immunology, dermatology, endocrine, and reproductive health. In this review, we aimed to provide insight into the association between sleep deprivation and the development of diseases. We reviewed the latest updates available in the literature and particular attention was paid to reports that detailed all possible causal relationships involving both extrinsic and intrinsic factors that may be relevant to this topic. Various mechanisms by which sleep deprivation may affect health were presented and discussed, and this review hopes to serve as a platform for ideas generation for future research.

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.

The Impact of Sleep and Circadian Disorders on Physician Burnout

Nearly 50% of physicians report symptoms of clinical burnout. Occupational factors and personal health play substantial roles in physician burnout. The role of sleep in physician burnout is not well understood. Burnout is at epidemic levels in health care, with research suggesting nearly one in two physicians experience clinical burnout as defined according to the Maslach Burnout Index. Sleep deprivation, burnout, and clinician health are intricately intertwined. The relation between sleep deprivation and burnout is not only suggested in hypothetical models but also confirmed in observational studies of workers of all types. Models describing the relation between burnout and sleep suggest as potential causative mechanisms of sleep disturbances the following: (1) a chronic depletion of energy stores; or (2) activation of the hypothalamic-pituitary-adrenal axis and increasing levels of bodily stress. Sleep deprivation and burnout are widespread in health-care workers, affecting not only nurses but also medical students, physicians-in-training, and practicing physicians. Although sleep deprivation is associated with clinical burnout, direct studies showing that sleep extension can improve burnout recovery are lacking. Early detection and early intervention to improve both sleep deprivation and burnout are warranted in health-care professionals. Interventions should be directed not only at individuals but also at the entire health system. This review highlights the latest developments and emerging concepts concerning the role of sleep and circadian disorders in physician burnout.

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.

Hemodynamic, Autonomic, and Vascular Function Changes after Sleep Deprivation for 24, 28, and 32 Hours in Healthy Men

This study aimed to analyze the impact of sleep deprivation (SD) on cardiac, hemodynamic, and endothelial parameters and to determine whether these are sustained with increased periods of SD. The study included 60 healthy men (mean: age 31.2±6.3 years; body mass index 24.6±2.6 kg/m²). Hemodynamic parameters, parameters of myocardial contractility, spectral analysis of heart rate (HR) and blood pressure (BP) variability, and the sensitivity of arterial baroreflex function were evaluated. Biochemical tests were performed to assess L-arginine (L-Arg) and asymmetric dimethylarginine (ADMA) levels in reflection of endothelial nitric oxide synthase ability. Measurements of cardiovascular system parameters were obtained at 9 a.m. (baseline) on the first day of the study and 9 a.m. (24-h SD), 1 p.m. (28-h SD), and 5 p.m. (32-h SD) on the second day. Blood samples for evaluating biochemical parameters were obtained at baseline and after 24-h SD. ANOVA Friedman's test revealed a significant effect for time in relation to HR (χ²=26.04, df=5, p=0.000), systolic BP (χ²=35.98, df=5, p=0.000), diastolic BP (χ²=18.01, df=5, p=0.003), and mean BP (χ²=28.32, df=5, p=0.000). L-Arg and ADMA levels changed from 78.2±12.9 and 0.3±0.1 at baseline to 68.8±10.2 and 0.4±0.1 after 24-hr SD, respectively (p=0.001, p=0.004). SD in healthy men is associated with increases in BP, which appear to occur after 24 hours of SD and are maintained over increasing periods of SD. The observed hemodynamic changes may have resulted due to disordered vascular endothelial function, as reflected in alterations in L-Arg and ADMA levels.

Relation of heart rate recovery after exercise testing to coronary artery calcification

BACKGROUND

We examined whether slow heart rate recovery (HRR) after exercise testing as an estimate of impaired autonomic function is related to coronary artery calcification (CAC), an emerging marker of coronary atherosclerosis.

METHODS

We evaluated 2088 men who participated in a health-screening program that included measures of CAC and peak or symptom-limited cardiopulmonary exercise testing. HRR was calculated as the difference between peak heart rate (HR) during exercise testing and the HR at 2 min of recovery after peak exercise. We measured CAC using multidetector computed tomography to calculate the Agatston coronary artery calcium score. Advanced CAC was defined as a mean CAC >75th percentile for each age group.

RESULTS

HRR was negatively correlated with CAC (r = -.14, p < .01). After adjusting for conventional risk factors, participants in the lowest quartile of HRR (<38 bpm) were 1.59 times (95% CI: 1.17-2.18; p < .05) more likely to have advanced CAC than their counterparts in the highest quartile of HRR (>52 bpm). Each 1 bpm decrease in HRR was associated with 1% increase in advanced CAC after adjusting for potential confounders.

CONCLUSIONS

An attenuated HRR after exercise testing is associated with advanced CAC, independent of coronary risk factors and other related hemodynamic response. KEY MESSAGES Slow heart rate recovery (HRR) after maximal exercise testing, indicating decreased autonomic function, is associated with an increased risk of cardiovascular event and mortality. Slow HRR has been linked with the occurrence of malignant ventricular arrhythmias, but it remains unclear whether slow HRR is associated with an increased risk of coronary artery calcification (CAC), an emerging marker of coronary atherosclerosis. An attenuated HRR after exercise testing was associated with advanced CAC, independent of coronary risk factors and other potential hemodynamic confounder, supporting the hypothesis that slow HRR is related to the burden of atherosclerotic coronary artery disease.

An Official American Thoracic Society Statement: The Importance of Healthy Sleep. Recommendations and Future Priorities

RATIONALE

Despite substantial public interest, few recommendations on the promotion of good sleep health exist to educate health care providers and the general public on the importance of sleep for overall health.

OBJECTIVES

The aim of this American Thoracic Society (ATS) statement is to provide a review of the current scientific literature to assist health care providers, especially pulmonologists and sleep physicians, in making recommendations to patients and the general public about the importance of achieving good quality and adequate quantity of sleep.

METHODS

ATS members were invited, based on their expertise in sleep medicine, and their conclusions were based on both empirical evidence identified after comprehensive literature review and clinical experience.

MAIN RESULTS

We focus on sleep health in both children and adults, including the impact of occupation on sleep, the public health implications of drowsy driving, and the common sleep disorders of obstructive sleep apnea and insomnia. This ATS statement also delineates gaps in research and knowledge that should be addressed and lead to new focused research priorities to advance knowledge in sleep and sleep health.

CONCLUSIONS

Good quality and quantity of sleep are essential for good health and overall quality of life; therefore a strong recommendation was made for the implementation of public education programs on the importance of sleep health.

Effect of acute sleep deprivation on left atrial mechanics assessed by three-dimensional echocardiography

BACKGROUND

Although sleep deprivation (SD) affects cardiovascular system in many ways, physio-pathological changes in cardiac chamber volume and function have not been described well. The aim of the present study was to investigate the effect of SD on left atrial (LA) and ventricular function with three-dimensional (3D) echocardiography.

METHODS

Thirty-two healthy individuals (12 females, mean age 33.25 ± 8.18) were evaluated. Echocardiographic examination was performed once after a night of regular sleep and a night of sleep debt. Beside conventional parameters, 3D phasic volumes and function were measured using a commercially available 3D echocardiography system and offline analysis software.

RESULTS

Mean sleep duration of the study group was 8.15 ± 2.19 h in the day of regular sleep and 2.56 ± 2.25 h in the day of sleep deprivation. There was a significant prolongation in deceleration time (180.83 ± 15.34 vs. 166.44 ± 26.12; p = 0.044) and increase in E/e' (6.95 ± 1.26 vs. 6.38 ± 0.85; p = 0.005). Among 3D measurements, the difference in left ventricular ejection fraction (EF), LA EF, LA reservoir function and LA active EF were not significant. Mean LA passive EF of the individuals was significantly lower after night shift (24.10 ± 7.66 vs. 31.49 ± 7.75; p = 0.006).

CONCLUSION

Acute SD is associated with a reduction in LA passive emptying function in healthy adults. 3D-derived indices were sufficient to show subclinical diastolic dysfunction according to impairment in passive phase of LA ejection. Prospective large-scale studies are needed to enlighten this issue.