Racial/Ethnic Differences in the Associations Between Physical Activity and Sleep Duration: A Population-Based Study.

BACKGROUND: This study examined associations between physical activity (recreational, nonrecreational) and sleep duration among a nationally representative diverse sample of U.S. adults. METHODS: We used cross-sectional data from 9,205 National Health and Nutrition Examination Survey 2007 to 2012 participants aged 20 to 65 years who identified as White, Black, or Hispanic. Activity (ie, recreation, occupation, and transportation activity) was categorized into quartiles. Sleep duration was categorized as short (≤6 hours/night) or normal (>6 to ≤9 hours/night). Logistic regression was used to estimate associations of activity with sleep duration. RESULTS: Recommended levels of recreation activity and moderate levels of transportation activity were associated with normal sleep duration [Odds Ratio (OR): = 1.33, 95% Confidence Interval (CI) = 1.08, 1.65; OR = 1.28, 95% CI = 1.02, 1.62, respectively]. High occupation physical activity was associated with shorter sleep duration (OR = 0.59, 95% CI = 0.49, 0.71). Differences were observed by race/ethnicity in associations of recreation and occupation activity with sleep duration. CONCLUSIONS: White individuals who engaged in some recreation activity, relative to being inactive, had more favorable sleep duration; whereas, high levels of occupation activity were associated with worse sleep duration among White and Black individuals. Physical activity was not associated with sleep duration among Hispanics.

Positive psychological health and stroke risk: The benefits of emotional vitality.

OBJECTIVE: Stroke is a leading cause of death and disability. Various forms of positive psychological health (e.g., emotional vitality) are associated with lower risk for heart disease. However, it is unclear whether positive psychological health may also be beneficial for stroke risk. The purpose of the present study was to examine prospectively the association between emotional vitality and incident stroke in a nationally representative sample of 6,019 participants in the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study. METHODS: Emotional vitality was assessed via self-report at study baseline in 1971-1975. Stroke cases were identified from hospital/nursing home discharge reports and death certificates. Multivariate Cox proportional hazards regression models were used to estimate hazard ratios and 95% confidence intervals of incident stroke associated with a 1 SD increase in emotional vitality scores. Models were adjusted for traditional cardiovascular disease risk factors and subsequently for psychological distress. RESULTS: Higher emotional vitality was associated with lower risk of incident stroke over a mean of 16.29 (SD = 4.75) years of follow-up (hazard ratio = 0.89; 95% confidence interval: 0.81, 0.99). Findings persisted when controlling for traditional cardiovascular disease risk factors and psychological distress. CONCLUSIONS: Higher levels of emotional vitality were prospectively associated with lower stroke risk in a representative sample of the U.S. POPULATION: Associations were independent of psychological distress. Results point to the potential importance of positive psychological functioning for cardiovascular health and for stroke prevention. (PsycINFO Database Record

Stress, behavior, and biology: risk factors for cardiovascular diseases in youth.

Psychological stress reactivity is associated with atherogenesis in youth. The novel hypothesis is that stress promotes atherogenic behaviors, including snacking on energy-dense food and reducing physical activity, and increases adiposity. Stress also increases systolic blood pressure cardiovascular reactivity, which also may be atherogenic. Exercise dampens stress reactivity and may be one mechanism by which it protects against the development of cardiovascular diseases.

Utility of actiwatch sleep monitor to assess waking movement behavior in older women.

PURPOSE: Wrist-worn accelerometer devices measure sleep in free-living settings. Few studies, however, have investigated whether these devices can also measure waking movement behavior (e.g., total movement volume, physical activity). The purpose of this study was to investigate the ability of a wrist-worn Actiwatch 2 sleep monitor to rank total movement volume and physical activity levels compared with a waist-worn ActiGraph GT1M accelerometer and self-reported leisure time physical activity, respectively. In addition, we compared temporally matched activity measured via the ActiGraph GT1M and Actiwatch 2 over the study week. METHODS: A subset of women from the Healthy Women Study (n = 145; age, 73.3 ± 1.7 yr) wore an Actiwatch 2 on their nondominant wrist and an ActiGraph GT1M on their dominant hip for seven consecutive days. Participants recorded their leisure time physical activity in a 7-d diary and completed the past year version of the Modifiable Activity Questionnaire. Analyses were conducted for all wake periods and separately for active periods when both devices were worn. RESULTS: Spearman rank-order correlation coefficients for total movement volume between the Actiwatch 2 and ActiGraph GT1M were significant for wake periods (r = 0.47, P < 0.001) and, to a lesser extent, for active periods (r = 0.26, P < 0.01). However, the Actiwatch 2 did not rank participant's physical activity levels similarly to self-reported leisure time physical activity estimates (κ ≤ 0.05, P > 0.05). Multilevel model analyses comparing temporally matched activity measured via the ActiGraph GT1M and Actiwatch 2 suggest that the two devices yielded similar levels of activity during wake periods (B = 0.90; SE, 0.008; P < 0.001) and during active periods (B = 0.81; SE, 0.01; P < 0.001). CONCLUSIONS: A wrist-worn Actiwatch 2 may be useful for ranking total movement volume and for assessing the pattern of activity over a day in older women. However, our data do not support using a wrist-worn Actiwatch 2 device for measuring physical activity.

Sleep and executive function in older women: the moderating effect of physical activity.

BACKGROUND: Sleep and physical activity are both important for cognition. However, few cognitive function studies include comprehensive measurement of both sleep and physical activity. The purpose of this study was to examine the independent and interactive associations of sleep and physical activity in relation to cognitive function in older women. METHODS: A subset of 121 women from the Healthy Women Study, mean age 73.3 ± 1.7 years, wore an actigraphy sleep monitor, physical activity accelerometer, and kept sleep and physical activity diaries for 7 consecutive days. Executive function was measured with the Digit Symbol Substitution Test and the Trail Making Test B. Verbal fluency was assessed with a word generation task. RESULTS: In adjusted models, greater actigraphy-assessed sleep efficiency was associated with more correct responses on the Digit Symbol Substitution Test (ß = 0.35, SE = 0.15, p < 0.02). Sleep was not associated with verbal fluency. A significant interaction (p < 0.05) was observed between accelerometer-assessed physical activity and actigraphy-assessed sleep efficiency. Specifically, lower sleep efficiency was associated with poorer performance on both the Digit Symbol Substitution Test and the Trail Making Test B among women with low levels of physical activity but not among women with high levels of physical activity. CONCLUSIONS: Our findings suggest that greater levels of physical activity may attenuate the negative impact of poor sleep on executive function in older women, with the clearest effects observed using direct measurements of sleep and physical activity.

Flow-mediated dilation and exercise blood pressure in healthy adolescents.

OBJECTIVES: Exercise blood pressure is a robust predictor of cardiovascular disease risk. Endothelial dysfunction occurs early in development of cardiovascular disease and is associated with greater exercise blood pressure in adults. However, it is not yet clear whether endothelial function is associated with exercise blood pressure in youth. The purpose of this study was to examine the relationship between endothelial function, indexed by brachial artery flow-mediated dilation, and submaximal exercise blood pressure in healthy adolescents. DESIGN: Cross-sectional study. METHODS: Adolescents (N=45) completed a graded submaximal treadmill test. Blood pressure was measured during rest and each exercise stage. Ultrasound measurement of brachial artery flow-mediated dilation was completed on a separate visit. Pearson correlations and multiple regression were used to assess the unadjusted and multivariate adjusted associations between flow-mediated dilation and exercise blood pressure, respectively. RESULTS: Lower flow-mediated dilation was associated with lower diastolic blood pressure (r=0.37, p=0.01) and greater pulse pressure (r=-0.38, p=0.01) during exercise. The significance did not change when adjusting for age, gender, fitness, or resting blood pressure. Exploratory analyses suggest that flow-mediated dilation was associated with exercise diastolic blood pressure primarily among adolescents with low resting diastolic blood pressure. CONCLUSIONS: Studies in youth are important to understand the early pathogenesis of cardiovascular disease. Findings from this study suggest that endothelial function may play a role in regulating blood pressure responses during submaximal exercise in healthy adolescents.

Prospective study of anxiety and incident stroke.

BACKGROUND AND PURPOSE: Higher levels of anxiety are associated with increased risk for coronary heart disease. However, few studies have investigated whether anxiety is associated with stroke risk. The purpose of this study was to examine the association between anxiety symptoms and incident stroke in a nationally representative longitudinal study of the US population. METHODS: Participants (n=6019) in the First National Health and Nutrition Examination Survey were assessed at baseline and followed for 16.29±4.75 years. Multivariate Cox proportional hazards regression models were used to estimate hazard ratios and 95% confidence intervals of incident stroke associated with a 1 SD increase in anxiety symptoms. Models were adjusted for standard cardiovascular risk factors and additionally for depression. RESULTS: A total of 419 incident stroke cases were identified from hospital/nursing home discharge reports and death certificates. Reporting more anxiety symptoms at baseline was associated with increased risk of incident stroke after adjusting for standard biological and behavioral cardiovascular risk factors (hazard ratio, 1.14; 95% confidence interval, 1.03-1.25). Findings persisted when additionally controlling for depression. Exploratory analyses considering the role of potential confounding versus pathway variables suggested that behavioral factors may be a key pathway linking anxiety to stroke risk. CONCLUSIONS: Higher anxiety symptom levels were associated prospectively with increased risk for incident stroke independent of other risk factors, including depression. Anxiety is a modifiable experience that is highly prevalent among the general population. Its assessment and treatment may contribute to developing more effective preventive and intervention strategies for improving overall cardiovascular health.

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.

Physical activity and sleep among midlife women with vasomotor symptoms.

OBJECTIVE: Few studies have examined the relationship between physical activity and sleep among women with vasomotor symptoms. We examined the associations of habitual leisure time and household physical activity with sleep characteristics among women reporting vasomotor symptoms. METHODS: A subcohort of women (N = 52: white, 27; African American, 25) in the Study of Women's Health Across the Nation was assessed for self-reported and actigraphic sleep measurements for four nights. Women were between 54 and 63 years, were currently experiencing vasomotor symptoms, and were not taking selective serotonin reuptake inhibitors or hormone therapy. The associations between physical activity (leisure time and household) and sleep (diary, actigraphy, and global sleep quality), as well as interactions by race and body mass index, were assessed using logistic regression and generalized estimating equations. RESULTS: Greater leisure time physical activity was associated with higher odds of rating global sleep quality as good (OR, 8.08, 95% CI, 1.5, 44.5, P = 0.02). Greater household physical activity was associated with more favorable diary-reported sleep characteristics, including fewer awakenings during the night (B = -0.14, SE = 0.06, P = 0.01). Exploratory analyses suggest that household physical activity was associated with more favorable sleep characteristics primarily among white and nonobese women. CONCLUSIONS: Greater levels of habitual physical activity, particularly non-leisure time physical activity, are associated with more favorable sleep characteristics. Considering the potential impact of physical activity on sleep, even at the relatively modest levels characteristic of household physical activity, may be important for women with vasomotor symptoms, a subgroup at high risk for sleep problems.

Systolic blood pressure reactivity during submaximal exercise and acute psychological stress in youth.

BACKGROUND: Studies in youth show an association between systolic blood pressure (SBP) reactivity to acute psychological stress and carotid artery intima-media thickness (CIMT). Submaximal exercise produces similar cardiovascular responses as acute psychological stress and may be a valuable tool to assess SBP reactivity in youth. However, it has not yet been determined whether SBP reactivity during submaximal exercise in youth is associated with CIMT, as it is during psychological stress. METHODS: Fifty-four adolescents aged 13-16 years completed 3 visits. On one visit, adolescents completed three, 4-minute stages of increasing intensity on a treadmill. On another visit, adolescents completed measures of acute psychological stress reactivity (star tracing, speech preparation, speech). On a third visit, adolescents completed an ultrasound scan to measure CIMT. RESULTS: SBP reactivity during lower- (ß = 0.29, P = 0.03) and higher-intensity (ß = 0.31, P = 0.02) submaximal exercise was associated with greater CIMT. SBP reactivity during higher-intensity submaximal exercise was positively associated with SBP reactivity during star tracing (ß = 0.34, P = 0.01), speech preparation (ß = 0.37, P = 0.007), and speech (ß = 0.41, P = 0.003). CONCLUSIONS: Greater SBP reactivity during submaximal exercise in healthy adolescents was associated with greater CIMT, similar to SBP reactivity during acute psychological stress. Adolescents who had greater SBP reactivity during exercise also demonstrated greater SBP reactivity during the psychological stress tasks. Given that exercise testing can be standardized for comparison across studies, submaximal exercise tests may be a valuable tool to assess SBP reactivity in youth.

Excess heart rate and systolic blood pressure during psychological stress in relation to metabolic demand in adolescents.

Cardiovascular responses during exercise are matched to the increased metabolic demand, but this may not be the case during psychological stress. No studies to date have tested this hypothesis in youth. Fifty-four youth, ages 13-16 years completed two visits. Heart rate (HR), systolic blood pressure (SBP), and oxygen (O(2)) consumption were measured during a graded exercise test on one day and during psychological stress reactivity (star tracing, speech) on another day. Predicted HR and SBP values during psychological stress were calculated based on HR-O(2) and SBP-O(2) relationships calculated during graded exercise. At a given O(2) consumption, actual HR was greater (p<0.02) than predicted for all stress tasks. Actual SBP was greater (p<0.001) than predicted for all stress tasks. This was the first study to demonstrate that cardiovascular responses were in excess of what would be expected based on metabolic demand in youth.

Effect of increasing the choice of active options on children's physically active play.

OBJECTIVES: To determine whether increasing the choice of physical activity options increases the duration and intensity of children's physically active play. DESIGN: This cross-sectional laboratory study included gender (male and female) and choice group [single toy (no choice), three toys (low choice), five toys (high choice)] as between participant factors. METHODS: Boys and girls (n=36, 8-12 y) were stratified, randomly assigned to a choice group that always provided access to each participant's most liked active toy(s), and allowed 60 min of free time. The same sedentary alternatives were freely available to all participants. Physical activity outcomes were measured by accelerometry, heart rate, and direct observation. RESULTS: The number of active toys the children played with increased (p<0.001) across each choice group. Minutes spent in MPA were greater in the low choice (p<0.05) and high choice (p<0.02) groups than the no choice group. Active playtime was greater (p<0.01) in the low choice (79%) and high choice (95%) groups compared to the no choice group. Girls in the low and high choice groups had greater (p<0.05) percent heart rate reserve when compared to girls in the no choice group. There was no difference in the boys' percent heart rate reserve between the no choice, low choice and high choice groups. CONCLUSIONS: Increasing the choice of active toys increases both the duration and intensity of physically active play, especially in girls.

Metabolic and cardiovascular adjustments during psychological stress and carotid artery intima-media thickness in youth.

OBJECTIVE: Cardiovascular reactivity is associated with carotid artery intima-media thickness as early as childhood. Excess cardiovascular responses relative to the metabolic demand during psychological stress have been proposed as a mechanism for this association. However, it is not known whether excess cardiovascular responses in relation to the metabolic demand correlate with carotid artery intima-media thickness as strongly as traditionally measured cardiovascular reactivity. METHODS: Fifty-four adolescents, ages 13-16 years completed a graded exercise test in 1 day and measures of psychological stress reactivity (star tracing, speech) on another day. Heart rate, systolic blood pressure, and oxygen consumption were measured on both days. On a third visit adolescents completed an ultrasound scan to measure carotid artery intima-media thickness. RESULTS: Traditionally measured systolic blood pressure reactivity (ß=0.30, p=0.02, R(2) increase=0.09) and excess systolic blood pressure (ß=0.30, p=0.02, R(2) increase=0.08) while preparing a speech were associated with greater carotid artery intima-media thickness when controlling for demographic characteristics, fitness, and baseline systolic blood pressure. CONCLUSIONS: This study adds to the growing body of literature showing a link between systolic blood pressure reactivity to acute psychological stress and carotid artery intima-media thickness in youth. This was the first study to demonstrate that systolic blood pressure in excess of the metabolic demand during psychological stress was also associated with carotid artery-intima media thickness.

Interactive effects of dietary restraint and adiposity on stress-induced eating and the food choice of children.

The Individual Differences Model posits that individual differences in physiological and psychological factors explain eating behaviors in response to stress. The purpose was to determine the effects of individual differences in adiposity, dietary restraint and stress reactivity on children's energy intake and food choices. A total of 40 boys and girls, age 8-12 years, with wide ranges of dietary restraint, adiposity, and stress reactivity were measured for total energy intake and choice of energy dense 'comfort' and lower density 'healthy' foods following reading and speech stressor manipulations. When exploring the interaction of dietary restraint and stress reactivity, lower restraint/lower reactivity and lower restraint/higher reactivity were associated with reductions in energy intake (37-62 kcal) and comfort food (33-89 kcal). Higher restraint/lower reactivity was associated with consuming 86 fewer total kcal and 45 fewer kcal of comfort food. Only higher restraint/higher reactivity predicted increased energy intake (104 kcal) and comfort food (131 kcal). The interaction of dietary restraint and percentage body fat revealed that lower restraint/lower adiposity was associated with consuming 123 fewer kcal after being stressed with the entire reduction due to a decrease in comfort food. Lower restraint/higher adiposity was associated with consuming 116 kcal more after being stressed with 70% (81 kcal) of the increase in the form of comfort foods. Higher restraint/lower adiposity and higher restraint/higher adiposity were associated with smaller changes in total energy intake of 22 kcal and 1 kcal; respectively. Both restraint and adiposity moderated the effect of stress on energy intake and food choice. Children with greater adiposity may be at risk for stress-induced eating to contribute to their obesity.

Stress-induced cardiovascular reactivity and atherogenesis in adolescents.

OBJECTIVE: To examine the association between cardiovascular reactivity to a set of psychological stressors and carotid artery intima-media thickness, a marker of subclinical cardiovascular disease in healthy adolescents. METHODS: Participants were 25 boys and 23 girls age 14.2 ± 0.9 years who were measured for heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure reactivity to mirror-tracing, reaction time, speech preparation and ad lib speech tasks and for common carotid artery intima-media thickness. Sequential regression analyses were used to establish the incremental increase in R(2)(R(inc)(2)) for the prediction of intima-media thickness due to cardiovascular reactivity independent of age, BMI percentile, sex, socioeconomic status, and resting HR or BP. RESULTS: SBP reactivity while preparing (ß=0.0019, R(inc)(2)=0.09) and giving the speech (ß=0.0014, R(inc)(2)=0.10) and an aggregate reactivity score based on all 4 tasks (ß=0.0026, R(inc)(2)=0.11) independently predicted (p ≤ 0.05) mean carotid artery intima-media thickness. Neither DBP reactivity nor HR reactivity during any task were independent predictors of intima-media thickness. CONCLUSION: Stress-induced cardiovascular reactivity, and especially SBP reactivity, is associated with carotid intima-media thickness and the early pathogenesis of cardiovascular disease. The use of an aggregate stress reactivity index provides a more reliable reflection of trait SBP reactivity to psychological stress and increases the confidence that youth with greater cardiovascular stress reactivity may indeed have greater progression of subclinical cardiovascular disease.

Effect of a simulated active commute to school on cardiovascular stress reactivity.

PURPOSE: Stress-induced cardiovascular reactivity is associated with the pathogenesis of cardiovascular disease. This study tested whether a simulated active commute to school dampened cardiovascular reactivity to a cognitive stressor typical to what children might experience during school. METHODS: Forty children (20 girls and 20 boys) aged 10-14 yr were randomly assigned to simulated sedentary drive-to-school or active-commute (walking) groups. The walking group completed a self-paced 1.6-km walk on a treadmill while images from a real 1.6-km walk through a pleasant neighborhood that finished at a school were projected in front of them. The drive-to-school group sat in a chair and watched the same slideshow of images of the neighborhood environment. Standardized residualized gain scores of cardiovascular reactivity during a cognitive stressor, the Stroop task, were calculated and used as dependent variables. RESULTS: Children in the walking group self-selected a walking intensity of 60.6% +/- 1.6% HRmax and covered the 1.6-km distance in 21.5 +/- 0.5 min. Children in the walking group had lower HR (2 +/- 1 vs 11 +/- 1 bpm, P < 0.001), systolic blood pressure (4 +/- 1 vs 12 +/- 1 mm Hg, P < 0.001), pulse pressure (-4 +/- 1 vs 6 +/- 1 mm Hg, P < 0.001), and perceived stress (1.4 +/- 0.1 vs 3.0 +/- 0.1 cm, P < 0.001) reactivities to cognitive stress than the control group. CONCLUSIONS: Active commuting to school may dampen cardiovascular reactivity and perceived stress when confronted with stressful cognitive challenges during the school day. This may help reduce the risk for cardiovascular disease later in life.

Cardiovascular reactivity to psychological stress and carotid intima-media thickness in children.

The relationship between cardiovascular stress reactivity and carotid artery intima-media thickness (IMT) has been established in adults, but not yet studied in children. Cardiovascular reactivity to an ad lib speech was measured in 20 boys and 20 girls age 11.0 +/- 1.4 years. Measures included heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure reactivity, and mean common carotid artery IMT. Sequential regression analyses were used to establish the incremental increase in R(2) for the prediction of IMT due to cardiovascular reactivity independent of age, socioeconomic status, race, percentage body fat, and baseline BP or HR. SBP reactivity (beta=0.002, , p<.05), but not DBP reactivity (p=.12) or HR reactivity (p=.82), independently predicted carotid artery IMT. This study provides initial evidence that SBP reactivity is associated with IMT and perhaps the early pathogenesis of cardiovascular disease in childhood.