Shorter Sleep Predicts Longer Subsequent Day Sedentary Duration in Healthy Midlife Adults, but Not in Those with Sleep Apnea

Effects of daily sleep on physical activity after cardiac surgery

BACKGROUND

Maintaining physical activity is challenging after cardiac surgery. Postsurgical cardiac patients often experience sleep problems showing a reciprocal interaction with physical activity. As sleep and physical activity show day-to-day variations, their daily relationships need to be assessed. However, no studies have examined daily sleep-physical activity relationships in postsurgical cardiac patients.

OBJECTIVES

This study aimed to examine the effects of daily sleep factors on daily physical activity after cardiac surgery.

METHODS

Among 33 patients who underwent cardiac surgery at least 10 weeks earlier, 5 sleep and 4 physical activity variables were measured using a wrist-worn ActiGraph for 7 days. Mixed-effects models were applied for data analyses.

RESULTS

Most participants were male (57.6 %), non-Hispanic whites (63.6 %) who had coronary artery bypass graft surgery (54.6 %). Participants averaged 60.8 ± 10.1 years of age and 85.7 ± 91.2 months since surgery. They slept for an average of 385.6 ± 74.6 min (6.4 ± 1.2 h). Among sleep factors, greater number of awakenings (NOA) predicted lower next-day sedentary time. Higher sleep efficiency (SE) was associated with lower next-day sedentary time when not controlling for covariates. Among the psychosocial, demographic, and clinical covariates, higher comorbidity index was associated with fewer kcals expended, less daily moderate-to-vigorous physical activity, and more daily sedentary time.

CONCLUSIONS

Daily SE and NOA and individual health status, including comorbidity, should be assessed over time to support improvement of daily physical activity after cardiac surgery. Researchers should examine the relationship between NOA and next-day sedentary time with larger samples. Such research should address multiple psychosocial, demographic, and clinical factors and the potential mediating role of sleep.

The association between sedentary behavior and obstructive sleep apnea: a cross-sectional study from the NHANES (2007-2008 to 2015-2020)

BACKGROUND

Sedentary behavior (SB) may contribute to obesity and lower extremity fluid retention, which may favor the development of obstructive sleep apnea (OSA). However, linking sedentary behavior to OSA is unclear. The purpose of this study was to determine if there is an association between SB and OSA.

METHODS

Three typical questions in the NHANES questionnaire(①The frequency of feeling excessively sleepy per month. ②The frequency of gasping, snorting or stopping breathing per week. ③The frequency of snoring per week.) have been used for the assessment of OSA. A physical activity questionnaire(On a typical day, the amount of time you spend sitting or reclining.) was used to assess SB. This secondary analysis included National Health and Nutrition Examination Survey (NHANES) participants (unweighted = 20,115). Weighted sample and multiple logistic regression complex sample analysis techniques were used in this study.

RESULTS

After adjustment for confounders, participants with SB(> 8 h/d) had a higher risk of OSA compared to SB(< 4 h/d). Stratified analysis by gender showed that there was no significant association of SB and OSA in men. However, in women, with SB(< 4 h/d) as the reference, participants with(≥ 4 h/d) had an increased risk of OSA. By age-stratified analysis, the association of SB with OSA was stronger among older participants.

CONCLUSION

Analysis in this study showed a positive association between SB and OSA, more pronounced in women and participants older than 60 years old.

Sleep extension and cardiometabolic health: what it is, possible mechanisms and real-world applications

Short sleep duration is associated with heightened cardiometabolic disease risk and has reached epidemic proportions among children, adolescents and adults. Potential mechanisms underlying this association are complex and multifaceted, including disturbances in circadian timing, food intake and appetitive hormones, brain regions linked to control of hedonic eating, physical activity, an altered microbiome and impaired insulin sensitivity. Sleep extension, or increasing total sleep duration, is an emerging and ecologically relevant intervention with significant potential to advance our understanding of the mechanisms underlying the association between short sleep duration and the risk of cardiometabolic disease. If effective, sleep extension interventions have potential to improve cardiometabolic health across the lifespan. Existing data show that sleep extension is feasible and might have potential cardiometabolic health benefits, although there are limitations that the field must overcome. Notably, most existing studies are short term (2-8 weeks), use different sleep extension strategies, analyse a wide array of cardiometabolic health outcomes in different populations and, frequently, lack adequate statistical power, thus limiting robust scientific conclusions. Overcoming these limitations will require fully powered, randomized studies conducted in people with habitual short sleep duration and existing cardiometabolic risk factors. Additionally, randomized controlled trials comparing different sleep extension strategies are essential to determine the most effective interventions. Ongoing and future research should focus on elucidating the potential cardiometabolic health benefits of sleep extension. Such studies have high potential to generate crucial knowledge with potential to improve health and quality of life for those struggling with short sleep duration.

The role of insufficient sleep and circadian misalignment in obesity

Traditional risk factors for obesity and the metabolic syndrome, such as excess energy intake and lack of physical activity, cannot fully explain the high prevalence of these conditions. Insufficient sleep and circadian misalignment predispose individuals to poor metabolic health and promote weight gain and have received increased research attention in the past 10 years. Insufficient sleep is defined as sleeping less than recommended for health benefits, whereas circadian misalignment is defined as wakefulness and food intake occurring when the internal circadian system is promoting sleep. This Review discusses the impact of insufficient sleep and circadian misalignment in humans on appetite hormones (focusing on ghrelin, leptin and peptide-YY), energy expenditure, food intake and choice, and risk of obesity. Some potential strategies to reduce the adverse effects of sleep disruption on metabolic health are provided and future research priorities are highlighted. Millions of individuals worldwide do not obtain sufficient sleep for healthy metabolic functions. Furthermore, modern working patterns, lifestyles and technologies are often not conducive to adequate sleep at times when the internal physiological clock is promoting it (for example, late-night screen time, shift work and nocturnal social activities). Efforts are needed to highlight the importance of optimal sleep and circadian health in the maintenance of metabolic health and body weight regulation.

Association between sedentary time and sleep quality based on the Pittsburgh Sleep Quality Index among South Korean adults

Background

Sleep problems increase the risk of premature illness and death. We evaluated the association between sedentary time and sleep quality among South Korean adults.

Methods

The data of adults (aged ≥ 19 years) from the 2018 Korea Community Health Survey were analyzed. Sedentary time, which included hours spent sitting or lying down daily, was categorized into four standardized groups. Poor sleep quality was defined using the global cutoff point (> 5 points) of the Pittsburg Sleep Quality Index. Multiple logistic regression analyses were performed to identify the association between sedentary time (≤ 3.9, 4.0–5.9, 6.0–7.9, and ≥ 8 hours /day) and sleep quality, by sex.

Results

Of the 224,118 participants, 35,784/100,454 men (35.6%) and 58,271/123,664 women (47.1%) had poor sleep quality. Compared with ≤ 3.9 h/day, sedentary times 4.0–5.9, 6.0–7.9, and ≥ 8 h/day were associated with worse sleep quality among men (odds ratio [OR]: 1.12, 95% confidence interval [CI]: 1.08–1.16; OR: 1.19, 95% CI: 1.14–1.25; OR: 1.30, 95% CI: 1.25–1.34, respectively) and women (OR: 1.06, 95% CI: 1.03–1.10; OR: 1.12, 95% CI: 1.08–1.16; OR: 1.22, 95% CI: 1.18–1.26, respectively). In subgroup analyses of sleep quality, subjective sleep quality, latency, disturbance, use of sleeping medication, and daytime dysfunction showed a strong dose-response relationship with increasing sedentary time in both sexes.

Conclusions

Regardless of sex, the longer the sedentary time, the stronger the association with poor sleep quality. Nationwide efforts are required to recommend standards for sedentary time and develop evidenced-based healthy behavior guidelines.