Association between time-of-day for eating, exercise, and sleep with blood pressure in adults with elevated blood pressure or hypertension: a systematic review.

The purpose of this review is to synthesize results from studies examining the association between time-of-day for eating, exercise, and sleep with blood pressure (BP) in adults with elevated BP or hypertension. Six databases were searched for relevant publications from which 789 were identified. Ten studies met inclusion criteria. Four studies examined time-of-day for eating, five examined time-of-day for exercise, and one examined time-of-day for sleep and their associations with BP. Results suggested that later time-of-day for eating ( n  = 2/4) and later sleep mid-point ( n  = 1/1) were significantly related to higher BP in multivariable models, whereas morning ( n  = 3/5) and evening ( n  = 4/5) exercise were associated with significantly lower BP. Although this small body of work is limited by a lack of prospective, randomized controlled study designs and underutilization of 24 h ambulatory BP assessment, these results provide preliminary, hypothesis-generating support for the independent role of time-of-day for eating, exercise, and sleep with lower BP.

Sleep Variability, Eating Timing Variability, and Carotid Intima-Media Thickness in Early Adulthood.

Background Day-to-day variability in sleep patterns and eating timing may disrupt circadian rhythms and has been linked with various adverse cardiometabolic outcomes. However, the extent to which variability in sleep patterns and eating timing relate to atherosclerotic development in subclinical stages remains unclear. Methods and Results Generally healthy adults (N=62, 29.3±7.3 years, 66% female) completed 14 days of sleep and dietary assessments via wrist accelerometry and photo-assisted diet records, respectively. Variability in sleep duration, sleep onset, eating onset (time of first caloric consumption), eating offset (time of last caloric consumption), and caloric midpoint (time at which 50% of total daily calories are consumed) were operationalized as the SD across 14 days for each variable. Separate regression models evaluated the cross-sectional associations between sleep and eating variability metrics with end-diastolic carotid intima-media thickness (CIMT) measured via ultrasonography. Models adjusted for age, sex, systolic blood pressure, sleep duration, and total energy intake. Each 60-minute increase in sleep duration SD and sleep onset SD were associated with a 0.049±0.016 mm (P=0.003) and 0.048±0.017 mm (P=0.007) greater CIMT, respectively. Variability in eating onset and offset were not associated with CIMT; however, each 60-minute increase in caloric midpoint SD was associated with a 0.033±0.015 mm greater CIMT (P=0.029). Exploratory post hoc analyses suggested that sleep duration SD and sleep onset SD were stronger correlates of CIMT than caloric midpoint SD. Conclusions Variability in sleep patterns and eating timing are positively associated with clinically relevant increases in CIMT, a biomarker of subclinical atherosclerosis, in early adulthood.

Associations of social isolation and loneliness with the onset of insomnia symptoms among middle-aged and older adults in the United States: A population-based cohort study.

There is an inconsistent conclusion regarding the relationship of social isolation and loneliness with poor sleep. We investigated the associations of social isolation and loneliness with new-onset insomnia symptoms in a nationally-representative sample of 9,430 adults aged ≥50 who were free of any insomnia symptoms/sleep disorders at baseline (wave 12/13) and followed up to 4 years from the Health and Retirement Study. Social isolation was measured by Steptoe's Social Isolation Index. Loneliness was measured by the revised 3-item UCLA-Loneliness Scale. Insomnia symptoms were quantified using the modified Jenkins Sleep Questionnaire. During a mean follow-up of 3.52 years, 1,522 (16.1%) participants developed at least one insomnia symptom. Cox models showed that loneliness was associated with the onset of difficulties initiating or maintaining sleep, early-morning awakening, nonrestorative sleep, and at least one of these symptoms after adjusting for potential covariates; while social isolation was not associated with the onset of difficulties maintaining sleep, early-morning awakening, or at least one insomnia symptom after adjusting for health indicators. These results are consistent in sensitivity analyses and stratified analyses by age, sex, race/ethnicity, and obesity. Public health interventions aimed at fostering close emotional relationships may reduce the burden of poor sleep among middle-aged and older adults.

Temporal associations between nightly sleep with daytime eating and activity levels in free-living young adults.

STUDY OBJECTIVES: This study aimed to quantify the temporal associations between nightly sleep quantity and timing with daytime eating behavior and activity levels in free-living (i.e. non-experimental) settings. METHODS: Generally healthy young adults (N = 63; 28.9 ± 7.1 years) completed concurrent sleep (wrist actigraphy), eating (photo-assisted diet records), and activity (waist actigraphy) assessments over 14 days. Multilevel models quantified the associations between nightly sleep (total sleep time, timing of sleep and wake onset) with next-day eating behavior (diet quality, caloric intake, timing of eating onset/offset, eating window duration) and activity levels (total physical activity, sedentary time). Associations in the reverse direction (i.e. eating and activity predicting sleep) were explored. Models adjusted for demographic and behavioral confounders and accounted for multiple testing. RESULTS: At within- and between-subject levels, nights with greater-than-average total sleep time predicted a shorter eating window the next day (all p ≤ 0.002). Later-than-average sleep and wake timing predicted within- and between-subject delays in next-day eating onset and offset, and between-subject reductions in diet quality and caloric intake (all p ≤ 0.008). At within- and between-subject levels, total sleep time was bidirectionally, inversely associated with sedentary time (all p < 0.001), while later-than-average sleep and wake timing predicted lower next-day physical activity (all p ≤ 0.008). CONCLUSIONS: These data underscore the complex interrelatedness between sleep, eating behavior, and activity levels in free-living settings. Findings also suggest that sleep exerts a greater influence on next-day behavior, rather than vice versa. While testing in more diverse samples is needed, these data have potential to enhance health behavior interventions and maximize health outcomes.

Automated Insulin Delivery for Hypoglycemia Avoidance and Glucose Counterregulation in Long-Standing Type 1 Diabetes with Hypoglycemia Unawareness.

Objective: Automated insulin delivery (AID) may benefit individuals with long-standing type 1 diabetes where frequent exposure to hypoglycemia impairs counterregulatory responses. This study assessed the effect of 18 months AID on hypoglycemia avoidance and glucose counterregulatory responses to insulin-induced hypoglycemia in long-standing type 1 diabetes complicated by impaired awareness of hypoglycemia. Methods: Ten participants mean ± standard deviation age 49 ± 16 and diabetes duration 34 ± 16 years were initiated on AID. Continuous glucose monitoring was paired with actigraphy to assess awake- and sleep-associated hypoglycemia exposure every 3 months. Hyperinsulinemic hypoglycemic clamp experiments were performed at baseline, 6, and 18 months postintervention. Hypoglycemia exposure was reduced by 3 months, especially during sleep, with effects sustained through 18 months (P ≤ 0.001) together with reduced glucose variability (P < 0.01). Results: Hypoglycemia awareness and severity scores improved (P < 0.01) with severe hypoglycemia events reduced from median (interquartile range) 3 (3-10) at baseline to 0 (0-1) events/person·year postintervention (P = 0.005). During the hypoglycemic clamp experiments, no change was seen in the endogenous glucose production (EGP) response, however, peripheral glucose utilization during hypoglycemia was reduced following intervention [pre: 4.6 ± 0.4, 6 months: 3.8 ± 0.5, 18 months: 3.4 ± 0.3 mg/(kg·min), P < 0.05]. There were increases over time in pancreatic polypeptide (Pre:62 ± 29, 6 months:127 ± 44, 18 months:176 ± 58 pmol/L, P < 0.01), epinephrine (Pre: 199 ± 53, 6 months: 332 ± 91, 18 months: 386 ± 95 pg/mL, P = 0.001), and autonomic symptom (Pre: 6 ± 2, 6 months: 6 ± 2, 18 months: 10 ± 2, P < 0.05) responses. Conclusions: AID led to a sustained reduction of hypoglycemia exposure. EGP in response to insulin-induced hypoglycemia remained defective, however, partial recovery of glucose counterregulation was evidenced by a reduction in peripheral glucose utilization likely mediated by increased epinephrine secretion and, together with improved autonomic symptoms, may contribute to the observed clinical reduction in hypoglycemia.

Social Isolation, Sleep Disturbance, and Cognitive Functioning (HRS): A Longitudinal Mediation Study.

BACKGROUND: Social isolation is prevalent and associated with dementia, yet the directionality and mechanisms are less understood. This study examined the association between social isolation and cognitive functioning and explored the mediating role of sleep disturbance on the social isolation-cognition relationship. METHODS: Data from 5 753 dementia-free Americans aged ≥50 of 2006 (T1), 2010 (T2), and 2014 (T3) waves of the Health and Retirement Study. Social isolation was measured by the Steptoe Social Isolation Index. Cognitive functioning was measured by the Telephone Interview of Cognitive Status. Sleep disturbance was measured with the modified Jenkins Sleep Scale. We used cross-lagged panel models to determine the associations between social isolation, sleep disturbance, and cognitive functioning. RESULTS: Social isolation is significantly associated with subsequent cognitive functioning (T1 to T2: ß = -0.055, standard error [SE] = 0.014, p < .001; T2 to T3: ß = -0.044, SE = 0.016, p < .001). Lower cognitive functioning is significantly associated with greater subsequent social isolation (T1 to T2: ß = -0.101, SE = 0.020, p < .001; T2 to T3: ß = -0.058, SE = .011, p < .001). Sleep disturbance at T2 partially mediated the effect of social isolation (T1) on cognitive functioning (T3), accounting for 6.2% of the total effect (ß = -0.003, SE = 0.001, p < .01). CONCLUSIONS: Social isolation may deteriorate cognitive functioning and vice versa. The association between social isolation and cognition is partially explained by sleep disturbance.

Sleep and Alertness Among Interns in Intensive Care Compared to General Medicine Rotations: A Secondary Analysis of the iCOMPARE Trial.

BACKGROUND: Medical interns are at risk for sleep deprivation from long and often rotating work schedules. However, the effects of specific rotations on sleep are less clear. OBJECTIVE: To examine differences in sleep duration and alertness among internal medicine interns during inpatient intensive care unit (ICU) compared to general medicine (GM) rotations. METHODS: This secondary analysis compared interns during a GM or ICU rotation from a randomized trial (2015-2016) of 12 internal medicine residency programs assigned to different work hour limit policies (standard 16-hour shifts or no shift-length limits). The primary outcome was sleep duration/24-hour using continuous wrist actigraphy over a 13-day period. Secondary outcomes assessed each morning during the concomitant actigraphy period were sleepiness (Karolinska Sleepiness Scale [KSS]), alertness (number of Brief Psychomotor Vigilance Test [PVT-B] lapses), and self-report of excessive sleepiness over past 24 hours. Linear mixed-effect models with random program intercept determined associations between each outcome by rotation, controlling for age, sex, and work hour policy followed. RESULTS: Of 398 interns, 386 were included (n = 261 GM, n = 125 ICU). Average sleep duration was 7.00±0.08h and 6.84±0.10h, and number of PVT lapses were 5.5±0.5 and 5.7±0.7 for GM and ICU, respectively (all P > .05). KSS was 4.8±0.1 for both rotations. Compared to GM, ICU interns reported more days of excessive sleepiness from 12am-6am (2.6 vs 1.7, P < .001) and 6am-12pm (2.6 vs 1.9, P = .013) and had higher percent of days with sleep duration < 6 hours (27.6% vs 23.4%, P < .001). GM interns reported more days with no excessive sleepiness (5.3 vs 3.7, P < .001). CONCLUSIONS: Despite ICU interns reporting more excessive sleepiness in morning hours and more days of insufficient sleep (<6 hours), overall sleep duration and alertness did not significantly differ between rotations.

Actigraphy-derived rest--activity rhythms are associated with nocturnal blood pressure in young women.

INTRODUCTION: Misalignment between lifestyle behaviors and endogenous circadian rhythms is associated with elevated nocturnal blood pressure (BP) in experimental studies; however, less is known about free-living (i.e. nonlaboratory) circadian disruption and nocturnal BP. Additionally, sex-specific cardiovascular implications of circadian disruption are unclear. OBJECTIVE: To examine the associations between rest--activity rhythms (RAR), a field-based estimate of circadian disruption, and nocturnal BP characteristics in young men and women. METHODS: Fifty participants (20 ±â€Š1 years; 20 men/30 women) underwent 24-h ambulatory BP monitoring following 14 days of wrist actigraphy. RAR variables of interdaily stability (day-to-day consistency in RAR), intradaily variability (within-day fragmentation of RAR), and relative amplitude (difference between peak vs. trough activity) were derived from actigraphy. Multivariable regression models of mean nocturnal SBP, DBP, and SBP dipping were generated to test main associations with RAR variables, and sex × RAR interactions. Daytime BP, race, BMI, physical activity, sleep duration, alcohol, caffeine, and sodium intake were considered as covariates. RESULTS: In the full sample, no main associations between RAR and nocturnal BP characteristics were found. Sex interacted with RAR such that in women, higher interdaily stability (ß = -5.39, 95% CI = -10.04 to -0.73, P = 0.024) and relative amplitude (ß = -4.78, 95% CI = -9.22 to -0.34, P = 0.036) were both associated with lower nocturnal SBP. Sex-stratified multivariable models of nocturnal BP also revealed associations between interdaily stability and relative amplitude with SBP dipping in women (all P ≤ 0.01). No associations were apparent in men. CONCLUSION: Consistent and high-amplitude RAR are favorably associated with nocturnal BP characteristics in young women.

Rest-activity rhythms in emerging adults: implications for cardiometabolic health.

Emerging adulthood (18-25 years) represents a window of opportunity to modify the trajectory of cardiometabolic disease risk into older adulthood. Not known is the extent to which rest-activity rhythms (RAR) may be related to biomarkers of cardiometabolic health in this population. In this cross-sectional, observational study, 52 healthy emerging adults wore wrist accelerometers (14 consecutive days; 24 h/day) for assessment of nonparametric RAR metrics, including interdaily stability (IS; day-to-day RAR consistency), intradaily variability (IV; within-day RAR fragmentation), and relative amplitude (RA; robustness of RAR), as well as autocorrelation (correlation of rest/activity levels at 24-h lag-times). Cardiometabolic biomarkers, including body mass index (BMI), body fat percentage, blood pressure (BP), fasting lipids, glucose, and C-reactive protein (CRP) were assessed. Additional measures including physical activity, sleep duration, and habitual caffeine and alcohol consumption were also evaluated. A series of multivariable regression models of cardiometabolic biomarkers were used to quantify associations with RAR metrics. On average, participants were 20 ± 1 years of age (21 males, 31 females), non-obese, and non-hypertensive. All were nonsmokers and free of major diseases or conditions. In separate models, which adjusted for sex, BMI, moderate-vigorous physical activity, sleep duration, caffeine, and alcohol consumption, IS was inversely associated with total cholesterol (p ≤ 0.01) and non-HDL cholesterol (p < .05), IV was positively associated with CRP (p < .05), and autocorrelation was inversely associated with total cholesterol (p < .05) and CRP (p < .05). Conversely, associations between RA and cardiometabolic biomarkers were nonsignificant after adjustment for BMI, alcohol, and caffeine consumption. In conclusion, RAR metrics, namely, a higher IS, lower IV, and higher autocorrelation, emerged as novel biomarkers associated with more favorable indices of cardiometabolic health in this sample of apparently healthy emerging adults.

Habitual physical activity patterns in a nationally representative sample of U.S. adults.

Physical inactivity is a leading determinant of noncommunicable diseases. Yet, many adults remain physically inactive. Physical activity guidelines do not account for the multidimensionality of physical activity, such as the type or variety of physical activity behaviors. This study identified patterns of physical activity across multiple dimensions (e.g., frequency, duration, and variety) using a nationally representative sample of adults. Sociodemographic characteristics, health behaviors, and clinical characteristics associated with each physical activity pattern were defined. Multivariate finite mixture modeling was used to identify patterns of physical activity among 2003-2004 and 2005-2006 adult National Health and Nutrition Examination Survey participants. Chi-square tests were used to identify sociodemographic differences within each physical activity cluster and test associations between the physical activity clusters with health behaviors and clinical characteristics. Five clusters of physical activity patterns were identified: (a) low frequency, short duration (n = 730, 13%); (b) low frequency, long duration (n = 392, 7%); (c) daily frequency, short duration (n = 3,011, 55%); (d) daily frequency, long duration (n = 373, 7%); and (e) high frequency, average duration (n = 964, 18%). Walking was the most common form of activity; highly active adults engaged in more varied types of activity. High-activity clusters were comprised of a greater proportion of younger, White, nonsmoking adult men reporting moderate alcohol use without mobility problems or chronic health conditions. Active females engaged in frequent short bouts of activity. Data-driven approaches are useful for identifying clusters of physical activity that encompass multiple dimensions of activity. These activity clusters vary across sociodemographic and clinical subgroups.

Shift Workers Have Higher Blood Pressure Medicine Use, But Only When They Are Short Sleepers: A Longitudinal UK Biobank Study.

Background Some, but not all, studies report associations between shift work and hypertension, suggesting that particular subgroups may be at risk. We examined moderating effects of sleep duration and circadian preference on the relationship between shift work and new blood pressure (BP) medicine use at follow-up. Methods and Results Baseline and 5-year follow-up data from the UK Biobank cohort (N=9200) were used to generate logistic regression models for shift workers and nonshift workers. The moderating effects of sleep duration (short ≤6 hours; adequate 7-8 hours; long ≥9 hours) and circadian preference (morning "larks;" intermediate; evening "owls") at baseline were examined with new BP medicine use at follow-up, adjusting for age, sex, race, education, employment, urban/rural, cardiovascular disease family history, depression, alcohol intake, physical activity, diet, smoking, and body mass index. The sample was predominately middle aged (55.3±7.4), female (57.3%), and white (97.9%). Most reported adequate sleep duration (7-8 hours, 73.7%) and were intermediate type (65.3%); 8.0% were shift workers at baseline. Only 6.5% reported new BP medicine use at follow-up. Short sleep duration was a significant moderator of new BP medicine use in shift workers. Among short sleepers, shift workers had a 2.1-fold increased odds of new BP medicine use compared with nonshift workers (odds ratio=2.08, 95% CI=1.21-3.58, P=0.008). In those reporting adequate (odds ratio=0.82, 95% CI=0.54-1.25, P=0.35) and long sleep (odds ratio=0.64, 95% CI=0.11-3.54, P=0.60), this relationship was protective but nonsignificant. Interaction between circadian preference and shift work on BP medicine use was nonsignificant. Conclusions Shift workers with short sleep duration may be at risk for hypertension.

Sleep and Alertness in a Duty-Hour Flexibility Trial in Internal Medicine.

BACKGROUND: A purpose of duty-hour regulations is to reduce sleep deprivation in medical trainees, but their effects on sleep, sleepiness, and alertness are largely unknown. METHODS: We randomly assigned 63 internal-medicine residency programs in the United States to follow either standard 2011 duty-hour policies or flexible policies that maintained an 80-hour workweek without limits on shift length or mandatory time off between shifts. Sleep duration and morning sleepiness and alertness were compared between the two groups by means of a noninferiority design, with outcome measures including sleep duration measured with actigraphy, the Karolinska Sleepiness Scale (with scores ranging from 1 [extremely alert] to 9 [extremely sleepy, fighting sleep]), and a brief computerized Psychomotor Vigilance Test (PVT-B), with long response times (lapses) indicating reduced alertness. RESULTS: Data were obtained over a period of 14 days for 205 interns at six flexible programs and 193 interns at six standard programs. The average sleep time per 24 hours was 6.85 hours (95% confidence interval [CI], 6.61 to 7.10) among those in flexible programs and 7.03 hours (95% CI, 6.78 to 7.27) among those in standard programs. Sleep duration in flexible programs was noninferior to that in standard programs (between-group difference, -0.17 hours per 24 hours; one-sided lower limit of the 95% confidence interval, -0.45 hours; noninferiority margin, -0.5 hours; P = 0.02 for noninferiority), as was the score on the Karolinska Sleepiness Scale (between-group difference, 0.12 points; one-sided upper limit of the 95% confidence interval, 0.31 points; noninferiority margin, 1 point; P<0.001). Noninferiority was not established for alertness according to the PVT-B (between-group difference, -0.3 lapses; one-sided upper limit of the 95% confidence interval, 1.6 lapses; noninferiority margin, 1 lapse; P = 0.10). CONCLUSIONS: This noninferiority trial showed no more chronic sleep loss or sleepiness across trial days among interns in flexible programs than among those in standard programs. Noninferiority of the flexible group for alertness was not established. (Funded by the National Heart, Lung, and Blood Institute and American Council for Graduate Medical Education; ClinicalTrials.gov number, NCT02274818.).

Sleep as a Target for Optimized Response to Smoking Cessation Treatment.

Declining national rates of current tobacco use to an all-time low of 15.1% represents a public health victory. Undermining this progress, however, are smoking rates of up to 50% among high-risk, low-income populations. Current FDA-approved treatments for nicotine dependence are ineffective with between 70-95% of treatment-seekers relapsing within the first year of attempted abstinence. Thus, identification of novel intervention targets to optimize response to currently available treatments for nicotine dependence is a critical next step. One such target may be sleep insomnia. Insomnia is a clinically verified nicotine withdrawal symptom but, to date, addressing insomnia or other sleep disturbance symptoms as an adjunctive smoking cessation therapy has yet to be fully considered. To this end, this manuscript presents a narrative review of: (1) sleep continuity and architecture in smokers versus nonsmokers; (2) effects of nicotine abstinence on sleep; (3) possible mechanisms linking sleep with smoking cessation outcomes; (4) plausible adjunctive sleep therapies to promote smoking cessation; (5) possible treatments for unhealthy sleep in smokers; and (6) directions for future research. Taken together, this will provide conceptual support for sleep therapy as an adjunctive treatment for smoking cessation. Implications: This narrative literature review presents a comprehensive discussion of the relationship between habitual sleep and cigarette smoking. The extent to which unhealthy sleep in smokers may be a viable intervention target for promoting response to smoking cessation treatment is considered. Ultimately, this review provides conceptual support for sleep therapy as an adjunctive treatment for smoking cessation.