Reduced physical activity in adults at risk for type 2 diabetes who curtail their sleep

Sleep deprivation in development of obesity, effects on appetite regulation, energy metabolism, and dietary choices

Sleep deprivation, which is a decrease in duration and quality of sleep, is a common problem in today's life. Epidemiological and interventional investigations have suggested a link between sleep deprivation and overweight/obesity. Sleep deprivation affects homeostatic and non-homoeostatic regulation of appetite, with the food reward system playing a dominant role. Factors such as sex and weight status affect this regulation; men and individuals with excess weight seem to be more sensitive to reward-driven and hedonistic regulation of food intake. Sleep deprivation may also affect weight through affecting physical activity and energy expenditure. In addition, sleep deprivation influences food selection and eating behaviours, which are mainly managed by the food reward system. Sleep-deprived individuals mostly crave for palatable energy-dense foods and have low desire for fruit and vegetables. Consumption of meals may not change but energy intake from snacks increases. The individuals have more desire for snacks with high sugar and saturated fat content. The relationship between sleep and the diet is mutual, implying that diet and eating behaviours also affect sleep duration and quality. Consuming healthy diets containing fruit and vegetables and food sources of protein and unsaturated fats and low quantities of saturated fat and sugar may be used as a diet strategy to improve sleep. Since the effects of sleep deficiency differ between animals and humans, only evidence from human subject studies has been included, controversies are discussed and the need for future investigations is highlighted.

In Search of Environmental Factors Associated With Global Differences in Birth Weight and BMI

OBJECTIVE

The "fetal origin of adult diseases hypothesis" encompasses the notion that intrauterine growth restriction (IUGR) alters fetal development trajectories. Various neonatal metrics inform IUGR, but not all contributors to IUGR have an impact on development trajectories. Chronic IUGR (twins) and slowly varying IUGR (seasonal) have little to no effect on later life trajectories. Perhaps development trajectories may evolve through other mechanisms, as for example, multiple short-lived periods of IUGR and repeated stimulation of metabolic pathways.

METHODS

Daily temperature variation could deliver a frequent IUGR as pregnant women would experience some degree of placental vasoconstriction during maximum/midday temperatures. We assessed the association with daily temperature amplitudes for globally distributed records of crude fetal growth rates (CFGR) and BMI. Paired birthweight (BW) and gestational age (GA) data permitted analyses of CFGR in 70 countries and subsequent analysis of CFGR for association with daily temperature amplitude, seasonal temperature amplitude, mean annual temperature, calorie intake per day per-1 person-1, BMI, height, and socioeconomic conditions. Analog analyses were performed for gestational age, calorie intake, BMI, and height.

RESULTS

CFGR and BMI showed a clear association with daily temperature amplitudes, which was not the case for gestational age, calorie intake, and height.

CONCLUSION

We show that daily temperature amplitudes are associated with both CFGR and BMI. These results permit a wider ecological appreciation of the hypothesis because daily temperature amplitudes inform environmental aridity and food scarcity. We discuss how scarcity, affluence, and the epidemiological environment influence the prevalence of afflictions associated with the fetal origin of adult disease hypothesis.

Methodological Choices on 24-h Movement Behavior Assessment by Accelerometry: A Scoping Review

BACKGROUND

There are no reviews describing current measurement protocols and accelerometer processing decisions that are being used in 24-h MovBeh studies, across the lifespan. We aim to synthesise information on methods for assessing 24-h movement behaviors using accelerometry across all age groups.

MAIN BODY

PubMed, PsycINFO, SPORTDiscus, and EMBASE were searched until December 2022. Observational or intervention reports describing accelerometry methods in studies on combinations of movement behaviors, with a 24-h protocol across all ages, were included. This review included 102 studies: three studies in toddlers, 15 in preschoolers, 17 in children, 23 in adolescents and 44 in adults and older adults. The Actigraph GT3X was the most commonly used device; the majority of the included reports collected data for seven days, including three weekdays and one weekend day, with a ≥ 16 h/day per 24-h period for valid data. The criteria for non-wear time varied between ≥ 20 and  ≥ 90 min of consecutive zero counts, depending on the age group. The most common epoch used was 15 or 60 s for youth and adults, respectively. The choice of sleep algorithms and SB/PA cut-points, of the included reports, depended on age and the original validation/calibration study. To deal with non-compliant participants, exclusion of non-compliant participants from the analysis was most frequently used. Most studies used diaries/logs to complement the accelerometer data.

CONCLUSIONS

Accelerometer protocols and methodological decisions varied considerably between reports. Therefore, consensus on methodological decisions is needed to improve precision and comparability between studies, which is challenging given the complexity of the procedures, the number of available brands and types of accelerometers, and the plethora of programming options.

The sleep for health study: A randomized clinical trial of the impact of insomnia treatment on glycemia in people with prediabetes

BACKGROUND

Insomnia is a modifiable risk factor for type 2 diabetes.

OBJECTIVE

Describe the methodology for the Sleep for Health study, a randomized clinical trial examining the effectiveness of digital cognitive behavioral therapy for insomnia (dCBT-I) in reducing hyperglycemia in 300 people with both insomnia and prediabetes.

OUTCOMES

Primary outcome is glucose level 2 h after a 75-g glucose load. Secondary outcomes include fasting glucose, hemoglobin A1c, insulin resistance score, mean glucose from continuous glucose monitoring (CGM), standard deviation of CGM values, and number of CGM values >140 mg/d.

METHODS

Participants with a hemoglobin A1c in the prediabetes range (5.7 % to 6.4 %) and clinically significant insomnia are randomized to a dCBT-I program or patient education control program. dCBT-I includes six sessions that focus on changing sleep habits and scheduling factors that affect sleep and addresses misconceptions about sleep and insomnia, utilizing interactive components and goal-setting. Those in the control arm receive access to a sleep-education website, which presents informational content in a simple, static form, without interactive components or active skills training, and all content is provided at once, rather than in modules that unlock over time. At baseline, 11 weeks and 33 weeks after randomization, participants undergo laboratory testing with a 2-h oral glucose tolerance test, hemoglobin A1c, and insulin resistance score. They also undertake 10 days of CGM and actigraphy wear and complete two dietary recalls.

SUMMARY

This trial is testing whether a program to improve sleep will positively impact glycemia among those with prediabetes. Registration with clinicaltrials.gov on October 3, 2023: NCT06067139.

Sleep Disturbances in Type 1 Diabetes and Mitigating Cardiovascular Risk

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in persons with type 1 diabetes (T1D). Despite control of known cardiovascular (CV) risk factors and better glycemic management, persons with T1D still face heightened CVD risk, suggesting additional contributing factors. Sleep has recently been recognized as a CV risk factor; however; the role of sleep in CVD specifically in T1D population has only started to emerge. Extensive evidence suggests that persons with T1D often encounter sleep disturbances. This review aims to comprehensively explore the relationship between sleep disturbances and CVD in T1D, proposed possible mediators including glycemic control, which has been studied more extensively, and less studied factors such as blood pressure, lipid metabolism, and weight management. Stress and self-care behaviors likely also play a role in the relationship between sleep disturbances and CVD. The evidence regarding sleep interventions in the context of T1D in mitigating these CV risk factors has recently been shown in early, small-scale studies. Sleep assessments should be a part of the standard of care in persons with T1D. Further research should focus on understanding the impact and mechanistic pathways of sleep disturbances on CV risk and developing T1D-specific sleep interventions to reduce CVD burden in this population.

Chronic insomnia, high trait anxiety and their comorbidity as risk factors for incident type 2 diabetes mellitus

The main objective of this study was to evaluate the association of the insomnia-anxiety comorbidity with incident type 2 diabetes (T2D) in a large prospective cohort. We selected adults without diabetes at baseline from the French NutriNet-Santé cohort who had completed the trait anxiety subscale of the Spielberger State-Trait Anxiety Inventory (STAI-T, 2013-2016) and a sleep questionnaire (2014); insomnia was defined according to established criteria. Using multivariable Cox models, we compared T2D risk across 4 groups: no insomnia or anxiety (reference), insomnia alone, anxiety alone (STAI-T ≥ 40), and comorbid anxiety and insomnia. Among 35,014 participants (mean baseline age: 52.4 ± 14.0 years; 76% women), 378 (1.1%) developed T2D over a mean follow-up of 5.9 ± 2.1 years. Overall, 28.5% of the sample had anxiety alone, 7.5%-insomnia alone, and 12.5%-both disorders. In the fully-adjusted model, a higher T2D risk was associated with anxiety-insomnia comorbidity (HR = 1.40; 95% CI 1.01, 1.94), but not with each disorder separately, compared to the group without insomnia or anxiety. The findings supported a positive association between anxiety-insomnia comorbidity and incident T2D among general-population adults. Future research using clinical diagnoses of mental disorders could confirm the findings and guide diabetes prevention programs.

Personal Activity Intelligence e-Health Program in People with Type 2 Diabetes: A Pilot Randomized Controlled Trial

INTRODUCTION

Innovative strategies are needed to enable people with type 2 diabetes (T2D) to self-manage physical activity (PA). Personal Activity Intelligence (PAI) is a new metric that uses the heart rate response to PA to inform the user as to whether they are doing enough PA to reduce the risk of premature mortality. The PAI score reflects PA over the previous 7 d with the goal to maintain a score ≥100. The aim of this study was to investigate the feasibility, acceptability, and efficacy of the PAI e-Health Program in people with T2D.

METHODS

Thirty participants with T2D who were not meeting PA guidelines were randomly assigned to 12 wk of either 1) PAI e-Health Program or 2) PA attention control. The PAI e-Health Program consisted of receiving a wrist-worn heart rate monitor and an app with the PAI metric, and attending 4 × 2 h·wk-1 sessions of exercise and counseling. Feasibility and acceptability of the program were evaluated by achievement of a PAI score ≥100 and participant feedback. Efficacy was determined from changes in glycemic control, cardiorespiratory fitness, exercise capacity (time-on-test), body composition, sleep time, and health-related quality of life.

RESULTS

Program participants in the PAI e-Health Program had a mean ± SD PAI score of 119.7 ± 60.6 and achieved ≥100 PAI on 56.4% of the days. The majority of participants (80%) intended to continue to use PAI monitoring. Compared with control, the PAI group significantly improved their exercise capacity (mean difference, 95% confidence interval) (63 s, 17.9-108.0 s), sleep time (67.2 min, 7.2-127.1 min), total percent body fat (-1.3%, -2.6% to -0.1%), and gynoid fat percent (-1.5%, -2.6 to -0.5).

CONCLUSIONS

The PAI e-Health Program is feasible, acceptable, and efficacious in people with T2D.

Associations of Diet Quality and Sleep Quality with Obesity

Short sleep duration or poor sleep quality has been associated with an increased risk of obesity. Although the underlying mechanism remains unclear, one proposed pathway is poor diet quality. This cross-sectional study investigated whether diet quality modifies the association between sleep status and obesity in Korean adults. We used the baseline data and samples of 737 men and 428 women (n = 1165) aged 19–64, who participated in the prospective Ewha–Boramae cohort study. Sleep duration was dichotomized into ≥7 h (adequate) and <7 h (insufficient). Pittsburgh Sleep Quality Index (PSQI) values, reflecting sleep quality, were dichotomized into >5 (poor quality) and ≤5 (good quality). Diet quality was evaluated by the Recommended Food Score (RFS). Obesity was associated with higher rates of insufficient sleep and poor sleep quality in women, but not in men. After adjustment for covariates, women with poor sleep quality had a higher risk of obesity than women with good sleep quality (OR = 2.198; 95% CI = 1.027–4.704); this association occurred only in the group with RFS ≤ median score. Our findings support a significant association between sleep quality and obesity, and this association has been potentially modified by dietary quality in women.

The impact of circadian timing on energy balance: an extension of the energy balance model

A significant proportion of the population is classified as having overweight or obesity. One framework which has attempted to explain biobehavioral mechanisms influencing the development of overweight and obesity is the energy balance model. According to this model, the body continually attempts to balance energy intake with energy expenditure. When energy intake and energy expenditure become imbalanced, there is an increase in homeostatic and allostatic pressure, generally to either increase energy intake or decrease energy expenditure, so as to restore energy homeostasis.Recent research has indicated that circadian aspects of energy intake and energy expenditure may influence energy balance. This paper provides a narrative review of existing evidence of the role of circadian timing on components of energy balance. Research on the timing of food intake, physical activity, and sleep indicates that unhealthy timing is likely to increase risk of weight gain. Public health guidelines focus on how much individuals eat and sleep, what foods are consumed, and the type and frequency of exercise, but the field of circadian science has begun to demonstrate that when these behaviors occur may also influence overweight and obesity prevention and treatment efforts.

Investigating the within-person relationships between activity levels and sleep duration using Fitbit data

The advancement of wearable technologies provides opportunities to continuously track individuals' daily activity levels and sleep patterns over extended periods of time. These data are useful in examining the reciprocal relationships between physical activity and sleep at the intrapersonal level. The purpose of this study is to test the bidirectional relationships between daily activity levels and sleep duration. The current study analyzed activity and sleep data collected from a Fitbit device as part of a 6 month employer-sponsored weight loss program. A total of 105 overweight/obese adults were included (92% female, 70% obese, and 44% Hispanic). Multilevel models were used to examine (a) whether daily active and sedentary minutes predicted that night's sleep duration and (b) whether sleep duration predicted active and sedentary minutes the following day. Potential extended effects were explored by using a 2 day average of the activity minutes/sleep duration as the predictor. No significant relationships between active minutes and sleep duration were found on a daily basis. However, having less sleep over two nights than one's usual level was associated with an increased likelihood of engaging in some physical activity the following day. There was a significant bidirectional negative association between sedentary minutes and sleep duration for both the daily and 2 day models. Data from wearable trackers, such as Fitbit, can be used to investigate the daily within-person relationship between activity levels and sleep duration. Future studies should investigate other sleep metrics that may be obtained from wearable trackers, as well as potential moderators and mediators of daily activity levels and sleep.

Daily associations between sleep and physical activity: A systematic review and meta-analysis

The day-to-day variations of sleep and physical activity are associated with various health outcomes in adults, and previous studies suggested a bidirectional association between these behaviors. The daily associations between sleep and physical activity have been examined in observational or interventional contexts. The primary goal of the current systematic review and meta-analysis was to summarize existing evidence about daily associations between sleep and physical activity outcomes at inter- and intra-individual level in adults. A systematic search of records in eight databases from inception to July 2019 identified 33 peer-reviewed empirical publications that examined daily sleep-physical activity association in adults. The qualitative and quantitative analyses of included studies did not support a bidirectional daily association between sleep outcomes and physical activity. Multilevel meta-analyses showed that three sleep parameters were associated with physical activity the following day: sleep quality, sleep efficiency, and wake after sleep onset. However, the associations were small, and varied in terms of direction and level of variability (e.g., inter- or intra-individual). Daytime physical activity was associated with lower total sleep time the following night at an inter-person level with a small effect size. From a clinical perspective, care providers should monitor the effects of better sleep promotion on physical activity behaviors in their patients. Future studies should examine sleep and physical activity during a longer period and perform additional sophisticated statistical analyses. SYSTEMATIC REVIEW REGISTRATION: https://osf.io/w6uy5/.

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

PURPOSE

Sedentary behavior and suboptimal sleep increase risks for chronic diseases. We hypothesized that sedentary behavior and sleep affect each other and that an underlying sleep disorder would alter these relationships. To test these hypotheses, we studied the bidirectional relationships between sedentary behavior and sleep (duration and efficiency) in healthy controls (HC) and people with untreated obstructive sleep apnea (OSA).

PATIENTS AND METHODS

Fifty-two volunteers (18 HC, 19 mild OSA [apnea/hypopnea index [AHI] range 5-14.9/hour], 15 moderate OSA [AHI range 15-29.9/hour]) were studied with actigraphy and sleep diaries across ~9 consecutive nights of self-selected consistent ~8-hour sleep episodes at home (range 4-21/nights per person). We analyzed whether total time asleep and sleep efficiency affected the subsequent daytime sedentary duration while controlling for body mass index and whether the severity of OSA altered this relationship. We also tested the reverse relationship, namely whether daytime sedentary duration affected the subsequent night's sleep and if any such relationship differed with OSA severity.

RESULTS

Overnight sleep duration and efficiency negatively predicted the subsequent day's sedentary duration in HC (p<0.02), but not in people with mild or moderate OSA (p>0.05). There was no significant reverse relationship between daytime sedentary duration and the subsequent night's sleep duration or efficiency (p≥0.2).

CONCLUSION

In healthy adults, short nighttime sleep predicts a longer duration of sedentary behavior on a subsequent day, but we did not observe this relationship in people with OSA. The mechanisms underlying this association in healthy individuals and its disruption in the presence of OSA need to be studied.

Self-reported sleep duration is associated with time in work physical activity but not transportation or leisure physical activity among Hispanic/Latino adults in the U.S.: results from the Hispanic Community Health Study/Study of Latinos

OBJECTIVES

The objective of this study is to test the hypothesis that short sleep duration is associated with fewer minutes of transportation, work, and leisure physical activity (PA).

DESIGN

This is a cross-sectional study conducted from 2008 to 2011.

SETTING

The study setting included four sites across the U.S. (Bronx, NY; Chicago, IL; Miami, FL; San Diego, CA).

PARTICIPANTS

A total of 14,653 Hispanic/Latino adults aged 18-74 years were enrolled as participants for the study.

MEASUREMENTS

Respondents reported sleep duration and transportation (including walking and cycling), work (including volunteering, paid work, and household chores), and leisure (including sports) PA domains and sociodemographic characteristics, other sleep characteristics, cardiometabolic health, health behaviors, and depressive symptoms.

RESULTS

In analyses weighted to reflect the Hispanic/Latino population of the four cities sampled, 61% had sleep duration 7-9 hours, 19% each had sleep duration < 7 hours and > 9 hours. Those sleeping < 7 hours spent 106 minutes/day in work-related PA, compared with those who spent fewer than 40 minutes/day in transportation-related or leisure-related PA. Sleep duration < 7 hours was associated with 26 minutes more in work-related PA (95% confidence interval [CI]: 16.7, 36.0), compared with sleep duration of 7-9 hours, adjusting for age and sex. Results were similar in employed respondents only, adjusting for occupation class and shift work frequency. Sleep duration was not associated with transportation-related or leisure-related PA.

CONCLUSIONS

Short sleep duration is associated with more work-related PA, both in the overall sample and among those employed. Individuals with higher work-related PA may face multiple demands and stressors that negatively influence sleep duration.

Effects of resistance exercise on adipokine factors and body composition in pre- and postmenopausal women

The objective of the present study was to examine effects of resistance exercise for 12 weeks on adipokine factors and body composition in postmenopausal (POM) women to provide basic data for preventing obesity or metabolic syndrome caused by menopause. Subjects of this study were 35 premenopausal (PRM) and POM women with body fat percentages of 30% or more. They were divided into PRM (n=15) and POM (n=20) groups. All subjects participated in resistance exercise training for 12 weeks. All serum samples were submitted for enzyme-linked immunosorbent assay measurements of adipokine factors. Body weight, muscle mass, body mass index, and waist-to-hip ration showed significant differences between the two groups after training. In contrast, body fat percentage did not differ between the groups, although it was significantly lower in the PRM group after exercise. Physical fitness was significant differences between the two groups after training, including grip strength (left and right), sit and reach, sit-ups, and standing long jump. In addition, grip strength (left), sit-up, and side step tests were significantly increased after exercise in the PRM group. There were the significant differences in interleukin-6 and leptin levels between the two groups after training. Interleukin-6, interleukin-15, and adiponectin levels were significantly higher in both groups after training compared to those before training, although leptin levels were significantly lower after exercise in the PRM group. Regular resistance exercise was found to be effective in decreasing body fat in PRM women, and decreased leptin and increased adiponectin were positively significant in both groups.

Daily physical activity and lung function decline in adult-onset asthma: a 12-year follow-up study

Background: There is a lack of knowledge on the association between daily physical activity and lung function in patients with asthma.

Objective: This study aims to examine the association between daily physical activity and asthma control, lung function, and lung function decline in patients with adult-onset asthma.

Design: This study is part of Seinäjoki Adult Asthma Study (SAAS), where 201 patients were followed for 12 years after asthma diagnosis. Daily physical activity was assessed at follow-up by a structured questionnaire and used to classify the population into subgroups of low (≤240 min) or high (>240 min) physical activity. Three spirometry evaluation points were used: 1. diagnosis, 2. the maximum lung function during the first 2.5 years after diagnosis (Max_0-2.5), 3. follow-up at 12 years.

Results: High physical activity group had slower annual FEV₁ (p<0.001) and FVC (p<0.018) decline. Additionally, the high physical activity group had higher FEV₁ values at follow-up, and higher FEV₁/FVC ratios at follow-up and diagnosis. There was no difference in BMI, smoking, medication, or frequency of physical exercise between high and low physical activity groups. Differences remained significant after adjustments for possible confounding factors.

Conclusion: This is the first demonstration of an association between long-term FEV₁ decline and daily physical activity in clinical asthma. Low physical activity is independently associated with faster decline in lung function. Daily physical activity should be recommended in treatment guidelines in asthma.

Short Sleep Duration Increases Metabolic Impact in Healthy Adults: A Population-Based Cohort Study

Objectives

The metabolic impact of inadequate sleep has not been determined in healthy individuals outside laboratories. This study aims to investigate the impact of sleep duration on five metabolic syndrome components in a healthy adult cohort.

Methods

A total of 162121 adults aged 20-80 years (men 47.4%) of the MJ Health Database, who were not obese and free from major diseases, were recruited and followed up from 1996 to 2014. Sleep duration and insomnia symptoms were assessed by a self-administered questionnaire. Incident cases of five metabolic syndrome components were identified by follow-up medical examinations. Cox proportional hazard ratios (HRs) were calculated for three sleep duration categories "< 6 hours/day (short)," "6-8 hours/day (regular)," and "> 8 hours/day (long)" with adjustment for potential confounding factors. Analyses were stratified by insomnia symptoms to assess whether insomnia symptoms modified the association between sleep duration and metabolic syndrome.

Results

Compared to regular sleep duration, short sleep significantly (p < .001) increased the risk for central obesity by 12% (adjusted HR 1.12 [1.07-1.17]), for elevated fasting glucose by 6% (adjusted HR 1.06 [1.03-1.09]), for high blood pressure by 8% (adjusted HR 1.08 [1.04-1.13]), for low high-density lipoprotein-cholesterol by 7% (adjusted HR 1.07 [1.03-1.11]), for hypertriglyceridemia by 9% (adjusted HR 1.09 [1.05-1.13]), and for metabolic syndrome by 9% (adjusted HR 1.09 [1.05-1.13]). Long sleep decreased the risk of hypertriglyceridemia (adjusted HR 0.89 [0.84-0.94]) and metabolic syndrome (adjusted HR 0.93 [0.88-0.99]). Insomnia symptoms did not modify the effects of sleep duration.

Conclusions

Sleep duration may be a significant determinant of metabolic health.

Cardiovascular Function of Modern Pigs Does not Comply with Allometric Scaling Laws

Growing concerns have been expressed regarding cardiovascular performance in modern farm pigs, which has been proposed as a critical factor contributing to the reduced adaptability of modern pigs to stress. Here we tested the hypothesis that cardiac dimensions and pump function in modern heavy farm pigs are disproportionally low for their body weight, and investigated potential underlying mechanisms. The results from the present study indeed demonstrate disproportionally low values for stroke volume and cardiac output in pigs with bodyweights over 150 kg. Importantly, these low values were not the result of impaired left ventricular (LV) systolic contractile function, but were due to a disproportionally small LV end-diastolic volume. The latter was associated with changes in determinants of LV passive stiffness, including (i) an increase in LV myocardial collagen, (ii) a shift from the compliant N2BA titin isoform towards the stiff N2B, and (iii) a marked elevation of aortic blood pressure. Taken together, these results demonstrate reduced pumping capacity of the hearts of heavy modern pigs, due to structural abnormalities in the LV myocardium.

Bidirectional associations of accelerometer-determined sedentary behavior and physical activity with reported time in bed: Women's Health Study

OBJECTIVE

To examine the day-to-day, bidirectional associations of accelerometer-derived sedentary behavior and physical activity (PA) with reported time in bed in a large cohort of older women.

METHODS

Data are from 10086 Women's Health Study participants (aged 71.6 years; SD, 5.7) who agreed to wear an accelerometer and complete a diary for 7 consecutive days. Generalized linear (multilevel) models with repeated measures were used to examine the adjusted associations of the following: (1) reported time in bed with next-day accelerometer-determined counts and time spent sedentary and in light- and moderate-to-vigorous-intensity PA (MVPA) and (2) accelerometer estimates with reported time in bed that night, expressed as short (<7 hours), optimal (7-9 hours), and long (>9 hours) sleep.

RESULTS

Across days, short sleep was associated with an average of 5500 (SE, 1352) higher accelerometer counts the following day but was also related to higher average sedentary (46.5 [SE, 1.5] minutes) and light-intensity PA (11.9 [SE, 1.2] minutes) than optimal sleep (all P<.001). Long sleep was associated with lower accelerometer counts, time spent sedentary and in light-intensity PA, and a reduced likelihood of engaging in ≥20 minutes of MVPA (all P<.001) than optimal sleep. Higher PA during the day (higher accelerometer counts and ≥20 minutes of accumulated MVPA) was associated with a reduced likelihood of reporting short or long sleep that night (all P<.001).

CONCLUSIONS

Findings support the bidirectional associations of accelerometer-determined sedentary behavior and PA with reported time in bed in older women. Future studies are needed to confirm findings with sleep actigraphy in older women.

Reduced Sleep Acutely Influences Sedentary Behavior and Mood But Not Total Energy Intake in Normal-Weight and Obese Women

Using a crossover design, 22 normal-weight and 22 obese women completed two free-living sleep conditions: (a) Normal Sleep: night of ~8 hr time in bed; and (b) Reduced Sleep: night of < 5 hr time in bed). Outcome measures were energy intake, physical activity and sedentary time, and mood. Sleep time was 7.7 ± 0.3 and 4.8 ± 0.2 hrs during the Normal Sleep and Reduced Sleep conditions, respectively (F = 1791.94; p < 0.0001). Energy intake did not differ between groups or as a function of sleep condition (F = 2.46; p = 0.1244). Sedentary time was ~ 30 min higher after the Reduced Sleep condition (F = 4.98; p = 0.0318); other physical activity outcomes were not different by condition (p > 0.05). Total mood score, depression, anger, vigor, fatigue, and confusion were worse after Reduced Sleep (p < 0.05). Reducing sleep acutely and negatively influenced sedentary time and mood in normal-weight and obese women.

The relation between sleep duration and sedentary behaviours in European adults

Too much sitting, and both short and long sleep duration are associated with obesity, but little is known on the nature of the relations between these behaviours. We therefore examined the associations between sleep duration and time spent sitting in adults across five urban regions in Europe. We used cross-sectional survey data from 6,037 adults (mean age 51.9 years (SD 16.4), 44.0% men) to assess the association between self-reported short (<6 h per night), normal (6-8 h per night) and long (>8 h per night) sleep duration with self-report total time spent sitting, time spent sitting at work, during transport, during leisure and while watching screens. The multivariable multilevel linear regression models were tested for moderation by urban region, age, gender, education and weight status. Because short sleepers have more awake time to be sedentary, we also used the percentage of awake time spent sedentary as an outcome. Short sleepers had 26.5 min day(-1) more sedentary screen time, compared with normal sleepers (CI 5.2; 47.8). No statistically significant associations were found with total or other domains of sedentary behaviour, and there was no evidence for effect modification. Long sleepers spent 3.2% higher proportion of their awake time sedentary compared with normal sleepers. Shorter sleep was associated with increased screen time in a sample of European adults, irrespective of urban region, gender, age, educational level and weight status. Experimental studies are needed to assess the prospective relation between sedentary (screen) time and sleep duration.

Sleep disturbances compared to traditional risk factors for diabetes development: Systematic review and meta-analysis

Sleep disturbances [short (<6 h) and long (>8 h) sleeping time, insomnia (initiating or maintaining sleep), obstructive sleep apnea (OSA) and abnormal sleep timing] have been associated with increased diabetes risk but the effect size relative to that of traditional risk factors is unknown. We conducted a systematic review and meta-analysis to compare the risk associated with sleep disturbances to traditional risk factors. Studies were identified from Medline and Scopus. Cohort studies measuring the association between sleep disturbances and incident diabetes were eligible. For traditional risk factors (i.e., overweight, family history, and physical inactivity), systematic reviews with or without meta-analysis were included. Thirty-six studies (1,061,555 participants) were included. Pooled relative risks (RRs) of sleep variables were estimated using a random-effect model. Pooled RRs of sleeping ≤5 h, 6 h, and ≥9 h/d were respectively 1.48 (95%CI:1.25,1.76), 1.18 (1.10,1.26) and 1.36 (1.12,1.65). Poor sleep quality, OSA and shift work were associated with diabetes with a pooled RR of 1.40 (1.21,1.63), 2.02 (1.57, 2.61) and 1.40 (1.18,1.66), respectively. The pooled RRs of being overweight, having a family history of diabetes, and being physically inactive were 2.99 (2.42,3.72), 2.33 (1.79,2.79), and 1.20 (1.11,1.32), respectively. In conclusion, the risk of developing diabetes associated with sleep disturbances is comparable to that of traditional risk factors. Sleep disturbances should be considered in clinical guidelines for type 2 diabetes screening.

Relationship between moderate-to-vigorous physical activity, abdominal fat and immunometabolic markers in postmenopausal women

OBJECTS

To assess the burden of levels of physical activity, non-esterified fatty acids (NEFA), triacylglycerol and abdominal fat on the immunometabolic profile of postmenopausal women.

STUDY DESIGN

Forty-nine postmenopausal women [mean age 59.43 (standard deviation 5.61) years] who did not undertake regular physical exercise participated in this study. Body composition was assessed using dual-energy X-ray absorptiometry, and levels of NEFA, tumour necrosis factor-α, adiponectin, insulin and triacylglycerol were assessed using fasting blood samples. The level of physical activity was assessed using an accelerometer (Actigraph GTX3x), and reported as counts/min, time spent undertaking sedentary activities and time spent undertaking moderate-to-vigorous physical activity (MVPA). The following conditions were considered to be risk factors: (i) sedentary lifestyle (<150min of MVPA per week); (ii) high level (above median) of abdominal fat; and (iii) hypertriacylglycerolaemia (<150mg/dl of triacylglycerol).

RESULTS

In comparison with active women, sedentary women had higher levels of body fat (%) (p=0.041) and NEFA (p=0.064). Women with higher levels of abdominal fat had impaired insulin resistance (HOMA-IR) (p=0.016) and spent more time undertaking sedentary activities (p=0.043). Moreover, the women with two risk factors or more had high levels of NEFA and HOMA-IR (p<0.05), as well as an eight-fold higher risk of a high level of NEFA, independent of age (p<0.05). No significant relationship was found between levels of physical activity, abdominal fat, tumour necrosis factor-α and adiponectin (p>0.05).

CONCLUSION

Postmenopausal women with a combination of hypertriacylglycerolaemia, a high level of abdominal fat and a sedentary lifestyle are more likely to have metabolic disturbances.

Onset of impaired sleep as a predictor of change in health-related behaviours; analysing observational data as a series of non-randomized pseudo-trials

BACKGROUND

Changes in health-related behaviour may be a key mechanism linking impaired sleep to poor health, but evidence on this is limited. In this study, we analysed observational data to determine whether onset of impaired sleep is followed by changes in health-related behaviours.

METHODS

We used data from 37,508 adults from the longitudinal Finnish Public Sector Study. In analysis of 59 152 person-observations on duration and quality of sleep and health-related behaviours (alcohol consumption, smoking, physical activity and weight control), data were treated as a series of non-randomized pseudo-trials with strict predefined criteria for data inclusion and temporality.

RESULTS

Smokers who experienced onset of short sleep were less likely to quit smoking than those with persistent normal sleep [odds ratio (OR) = 0.78, 95% confidence interval (CI): 0.64-0.97]. Onset of short sleep also predicted initiating high-risk alcohol consumption (OR = 1.17, 95% CI: 1.00-1.37). Onset of disturbed sleep was associated with changes in all assessed health-related behaviours: initiation of high-risk alcohol consumption (OR = 1.23, 95% CI: 1.05-1.45), quitting smoking (OR = 0.80, 95% CI: 0.63-1.00), becoming physically inactive (OR = 1.17, 95% CI: 1.06-1.30) and becoming overweight or obese (OR = 1.12, 95% CI: 1.01-1.23).

CONCLUSIONS

Findings suggest that the onset of short or disturbed sleep are risk factors for adverse changes in health-related behaviours. These findings highlight potential pathways linking impaired sleep to the development of lifestyle-related morbidity and mortality.

Are sleep duration and sleep quality associated with diet quality, physical activity, and body weight status? A population-based study of Canadian children

OBJECTIVES

To describe sleep duration and sleep characteristics, and to examine the associations between sleep duration and characteristics and body weight status, diet quality, and physical activity levels among grade 5 children in Nova Scotia.

METHODS

A provincially representative sample of 5,560 grade 5 children and their parents in Nova Scotia was surveyed. Parents were asked to report their child's bedtime and wake-up time, and to indicate how often their child snored or felt sleepy during the day. Dietary intake and physical activity were selfreported by children using the Harvard Youth/Adolescent Food Frequency Questionnaire and the Physical Activity Questionnaire for Children respectively. Body weight status was determined using measured heights and weights. Linear and logistic random effects models with children nested within schools were used to test for associations.

RESULTS

Approximately half of the surveyed parents reported that their children were not getting adequate sleep at night. Longer sleep duration was statistically significantly associated with decreased risk for overweight and obesity independent of other sleep characteristics (OR = 0.82, 95% CI: 0.73, 0.91). Longer sleep duration was also associated with better diet quality and higher levels of physical activity.

CONCLUSIONS

These findings indicate a need for health promotion strategies to encourage adequate sleep and to promote healthy sleep environments among children. Given the links among sleep, body weight status and lifestyle behaviours, these messages should be included in public health interventions aimed at preventing obesity and promoting health among children.

Sleep habits and diabetes

Sleep duration has been constantly decreasing over the past 50 years. Short sleep duration, sleep quality and, recently, long sleep duration have all been linked to poor health outcomes, increasing the risk of developing metabolic diseases and cardiovascular events. Beyond the duration of sleep, the timing of sleep may also have consequences. Having a tendency to go early to bed (early chronotype) compared with the habit of going to bed later (late chronotype) can interfere considerably with social schedules (school, work). Eventually, a misalignment arises in sleep timing between work days and free days that has been described as 'social jet lag'. The present review looks at how different sleep habits can interfere with diabetes, excluding sleep breathing disorders, and successively looks at the effects of sleep duration, chronotype and social jet lag on the risk of developing diabetes as well as on the metabolic control of both type 1 and type 2 diabetes. Finally, this review addresses the current state of knowledge of physiological mechanisms that could be linking sleep habits and metabolic health.

The metabolic burden of sleep loss

In parallel with the increasing prevalence of obesity and type 2 diabetes, sleep loss has become common in modern societies. An increasing number of epidemiological studies show an association between short sleep duration, sleep disturbances, and circadian desynchronisation of sleep with adverse metabolic traits, in particular obesity and type 2 diabetes. Furthermore, experimental studies point to distinct mechanisms by which insufficient sleep adversely affects metabolic health. Changes in the activity of neuroendocrine systems seem to be major mediators of the detrimental metabolic effects of insufficient sleep, through favouring neurobehavioural outcomes such as increased appetite, enhanced sensitivity to food stimuli, and, ultimately, a surplus in energy intake. The effect of curtailed sleep on physical activity and energy expenditure is less clear, but changes are unlikely to outweigh increases in food intake. Although long-term interventional studies proving a cause and effect association are still scarce, sleep loss seems to be an appealing target for the prevention, and probably treatment, of metabolic disease.

Sleep duration and cardiometabolic risk factors among individuals with type 2 diabetes

OBJECTIVE

To examine the association between sleep duration and cardiometabolic risk factors among individuals with recently diagnosed type 2 diabetes (n = 391).

METHODS

Sleep duration was derived using a combination of questionnaire and objective heart rate and movement sensing in the UK ADDITION-Plus study (2002-2007). Adjusted means were estimated for individual cardiometabolic risk factors and clustered cardiometabolic risk (CCMR) by five categories of sleep duration.

RESULTS

We observed a J-shaped association between sleep duration and CCMR - individuals sleeping 7 to <8 h had a significantly better CCMR profile than those sleeping ≥9 h. Independent of physical activity and sedentary time, individuals sleeping 7 to <8 h had lower triacylglycerol (0.62 mmol/l (0.29, 1.06)) and higher high-density lipoprotein (HDL)-cholesterol levels (0.23 mmol/l (0.16, 0.30)) compared with those sleeping ≥9 h, and a lower waist circumference (7.87 cm (6.06, 9.68)) and body mass index (BMI) (3.47 kg/m(2) (2.69, 4.25)) than those sleeping <6 h. Although sleeping 7 to <8 h was associated with lower levels of systolic and diastolic blood pressure, HbA1c, total cholesterol, and low-density lipoprotein (LDL)-cholesterol, these associations were not statistically significant.

CONCLUSIONS

Sleep duration has a J-shaped association with CCMR in individuals with diabetes, independent of potential confounding. Health promotion interventions might highlight the importance of adequate sleep in this high-risk population.

Temporal relationships between physical activity and sleep in older women

PURPOSE

The objective of this study is to examine the temporal and bidirectional relationships between accelerometer-derived physical activity estimates and actigraphy-assessed sleep characteristics among older women.

METHODS

A subgroup of participants (N = 143, mean age = 73 yr) enrolled in the Healthy Women Study wore an ActiGraph accelerometer on their waist and an Actiwatch sleep monitor on their wrist concurrently for seven consecutive days. Multilevel models examined whether ActiGraph-assessed daily activity counts (ct·min⁻¹·d⁻¹) and moderate- to vigorous-intensity physical activity (MVPA; min·d⁻¹) predicted Actiwatch-assessed sleep onset latency, total sleep time, sleep efficiency, and sleep fragmentation. Similar models were used to determine whether nighttime sleep characteristics predicted physical activity the following day.

RESULTS

In unadjusted models, greater daily activity counts (B = -0.05, P = 0.005) and more minutes of MVPA (B = -0.03, P = 0.01) were temporally associated with less total sleep time across the week. Greater sleep efficiency was associated with greater daily activity counts (B = 0.37, P = 0.01) and more minutes of MVPA (B = 0.64, P = 0.009) the following day. Less sleep fragmentation was also associated with greater daily activity counts and more MVPA the following day. Findings were similar after adjustment for age, education, body mass index, depressive symptoms, arthritis, and accelerometer wear time.

CONCLUSIONS

Few studies have used objective measures to examine the temporal relationships between physical activity and sleep. Notably, these findings suggest that nightly variations in sleep efficiency influence physical activity the following day. Thus, improving overall sleep quality in addition to reducing nightly fluctuations in sleep may be important for encouraging a physically active lifestyle in older women.

Short sleep duration is associated with decreased serum leptin, increased energy intake and decreased diet quality in postmenopausal women

OBJECTIVE

Short sleep duration induces hormonal perturbations contributing to hyperphagia, insulin resistance, and obesity. The majority of these studies are conducted in young adults. This analysis in a large (n = 769) sample of postmenopausal women (median age 63 years) sought to (a) confirm that sleep duration and sleep quality are negatively correlated with circulating leptin concentrations and (b) to examine the relationship between self-reported sleep, dietary energy intake, and diet quality, as well as, investigate the role of leptin in these associations.

METHODS

Sleep duration/quality, insomnia, and dietary intake were determined via self-report. Blood samples were collected following an overnight fast to assess serum leptin concentration. All analyses were adjusted for total body fat mass.

RESULTS

Women reporting ≤6 hr sleep/night had lower serum leptin concentrations than those reporting ≥8 hr sleep (P = 0.04). Furthermore, those with ≤6 hr sleep/night reported higher dietary energy intake (P = 0.01) and lower diet quality (P = 0.04) than the reference group (7 hr sleep/night). Women sleeping ≥8 hr also reported lower diet quality than the reference group (P = 0.02). Importantly, serum leptin did not confound these associations.

CONCLUSIONS

These results provide evidence that sleep duration is inversely associated with serum leptin and dietary energy intake in postmenopausal women.

Interactions between sleep, circadian function, and glucose metabolism: implications for risk and severity of diabetes

Sleep disturbances, including sleep insufficiency and sleep fragmentation, have been linked to abnormal glucose metabolism and increased diabetes risk. Well-controlled laboratory studies have provided insights regarding the underlying mechanisms. Several large prospective studies suggest that these sleep disturbances are associated with an increased risk of incident diabetes. Obstructive sleep apnea, which combines sleep fragmentation and hypoxemia, is a major risk factor for insulin resistance and possibly diabetes. Whether glycemic control in type 2 diabetes patients can be improved by treating sleep apnea remains controversial. Recently, sleep disturbances during pregnancy and their relationship to gestational diabetes and hyperglycemia have received considerable attention owing to potential adverse effects on maternal and fetal health. Additionally, evidence from animal models has identified disruption of the circadian system as a putative risk factor for adverse metabolic outcomes. The purpose of this review is to provide an update on the current state of knowledge linking sleep disturbances, circadian dysfunction, and glucose metabolism. Experimental, prospective, and interventional studies are discussed.

Better quality sleep promotes daytime physical activity in patients with chronic pain? A multilevel analysis of the within-person relationship

BACKGROUND

Promoting physical activity is key to the management of chronic pain, but little is understood about the factors facilitating an individual's engagement in physical activity on a day-to-day basis. This study examined the within-person effect of sleep on next day physical activity in patients with chronic pain and insomnia.

METHODS

119 chronic pain patients monitored their sleep and physical activity for a week in their usual sleeping and living environment. Physical activity was measured using actigraphy to provide a mean activity score each hour. Sleep was estimated with actigraphy and an electronic diary, providing an objective and subjective index of sleep efficiency (A-SE, SE) and a sleep quality rating (SQ). The individual and relative roles of these sleep parameters, as well as morning ratings of pain and mood, in predicting subsequent physical activity were examined in multilevel models that took into account variations in relationships at the 'Day' and 'Participant' levels.

RESULTS

Of the 5 plausible predictors SQ was the only significant within-person predictor of subsequent physical activity, such that nights of higher sleep quality were followed by days of more physical activity, from noon to 11 pm. The temporal association was not explained by potential confounders such as morning pain, mood or effects of the circadian rhythm.

CONCLUSIONS

In the absence of interventions, chronic pain patients spontaneously engaged in more physical activity following a better night of sleep. Improving nighttime sleep may well be a novel avenue for promoting daytime physical activity in patients with chronic pain.

Sleep restriction decreases the physical activity of adults at risk for type 2 diabetes

STUDY OBJECTIVE

To test the hypothesis that recurrent sleep curtailment will result in decreased physical activity in adults at risk for type 2 diabetes.

DESIGN

Two-condition 2-period randomized crossover study.

SETTING

University General Clinical Research Center.

PARTICIPANTS

Eighteen healthy patients with parental history of type 2 diabetes (9 females and 9 males, age 27 yr [standard deviation 3], body mass index 23.7 [2.3] kg/m²).

INTERVENTIONS

Two week-long inpatient sessions with 8.5 or 5.5-hr nighttime sleep opportunity. Participants who exercised regularly (39%) could follow their usual exercise routines during both sessions.

MEASUREMENTS AND RESULTS

Sleep and total body movement were measured by wrist actigraphy and waist accelerometry. Subjective mood and vigor was assessed using visual analog scales. The main outcome was the comparison of total activity counts between sleep conditions. Ancillary endpoints included changes in sedentary, light, and moderate plus vigorous activity, and their association with changes in mood and vigor. Daily sleep was reduced by 2.3 hr (P < 0.001) and total activity counts were 31% lower (P = 0.020) during the 5.5-hr time-in-bed condition. This was accompanied by a 24% reduction in moderate-plus-vigorous activity time (P = 0.005) and more sedentary behavior (+21 min/day; P = 0.020). The decrease in daily activity during the 5.5-hr time-in-bed condition was seen mostly in participants who exercised regularly (-39 versus -4% in exercisers versus nonexercisers; P = 0.027). Sleep loss-related declines in physical activity correlated strongly with declines in subjective vigor (R = 0.90; P < 0.001).

CONCLUSIONS

Experimental sleep restriction results in decreased amount and intensity of physical activity in adults at risk for type 2 diabetes.

Update on energy homeostasis and insufficient sleep

Driven by the demands and opportunities of modern life, many people habitually sleep less than 6 h a night. In the sleep clinic, chronic sleep restriction is recognized by the diagnosis of insufficient sleep syndrome (ICSD-9, 307.49-4), which is receiving increased scrutiny as a potential risk to metabolic health. Its relevance for the practicing endocrinologist is highlighted by a stream of epidemiological data that show an association of insufficient sleep with increased incidence of obesity and related morbidities. A central theme of this update is the notion that sleep loss incurs additional metabolic cost, which triggers a set of neuroendocrine, metabolic, and behavioral adaptations aimed at increasing food intake and conserving energy. Although this coordinated response may have evolved to offset the metabolic demands of extended wakefulness in natural habitats with limited food availability, it can be maladaptive in the context of a modern environment that allows many to overeat while maintaining a sedentary lifestyle without sufficient sleep. Importantly, such sleep loss-related metabolic adaptation may undermine the success of behavioral interventions based on reduced caloric intake and increased physical activity to lower metabolic risk in obesity-prone individuals. This emerging perspective is based on data from recently published human interventional studies and requires further experimental support. Nevertheless, it now seems prudent to recommend that overweight and obese individuals attempting to reduce their caloric intake and maintain increased physical activity should obtain adequate sleep and, if needed, seek effective treatment for any coexisting sleep disorders.

Changes in insulin secretion and action in adults with familial risk for type 2 diabetes who curtail their sleep

OBJECTIVE

Experimental sleep deprivation is accompanied by changes in glucose regulation. However, the effects of chronic sleep insufficiency on insulin secretion and action in populations at high risk for type 2 diabetes are not known. This study examined the relationship between objectively documented habitual sleep curtailment and measures of insulin sensitivity, insulin secretion, and oral glucose tolerance in free-living adults with parental history of type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 47 healthy participants with parental history of type 2 diabetes (26 female/21 male, mean [SD] age 26 [4] years and BMI 23.8 [2.5] kg/m(2)) completed 13 (SD = 2) days of sleep and physical activity monitoring by wrist actigraphy and waist accelerometry while following their usual lifestyle at home. Laboratory polysomnography was used to screen for sleep disorders. Indices of diabetes risk based on oral glucose tolerance tests were compared between participants with habitual short sleep and those with usual sleep duration >6 h/day.

RESULTS

Consistent with a behavioral pattern of habitual sleep curtailment, short sleepers obtained an average of 1.5 h less sleep per night and showed signs of increased sleep pressure. Participants who habitually curtailed their sleep had considerably higher indices of insulin resistance and increased insulin secretion but maintained normal glucose tolerance similar to that of subjects who slept more.

CONCLUSIONS

Young lean adults with parental history of type 2 diabetes who habitually curtail their sleep have increased insulin resistance and compensatory hyperinsulinemia--a pattern that has been associated with higher risk of developing diabetes in such susceptible individuals.