Customary physical activity and odds of depression: a systematic review and meta-analysis of 111 prospective cohort studies.

OBJECTIVE: To explore whether physical activity is inversely associated with the onset of depression, we quantified the cumulative association of customary physical activity with incident depression and with an increase in subclinical depressive symptoms over time as reported from prospective observational studies. DESIGN: Systematic review and meta-analysis. DATA SOURCES: MEDLINE, PsycINFO, PsycARTICLES and CINAHL Complete databases, supplemented by Google Scholar. ELIGIBILITY CRITERIA: Prospective cohort studies in adults, published prior to January 2020, reporting associations between physical activity and depression. STUDY APPRAISAL AND SYNTHESIS: Multilevel random-effects meta-analysis was performed adjusting for study and cohort or region. Mixed-model meta-regression of putative modifiers. RESULTS: Searches yielded 111 reports including over 3 million adults sampled from 11 nations in five continents. Odds of incident cases of depression or an increase in subclinical depressive symptoms were reduced after exposure to physical activity (OR, 95% CI) in crude (0.69, 0.63 to 0.75; I2=93.7) and adjusted (0.79, 0.75 to 0.82; I2=87.6) analyses. Results were materially the same for incident depression and subclinical symptoms. Odds were lower after moderate or vigorous physical activity that met public health guidelines than after light physical activity. These odds were also lower when exposure to physical activity increased over time during a study period compared with the odds when physical activity was captured as a single baseline measure of exposure. CONCLUSION: Customary and increasing levels of moderate-to-vigorous physical activity in observational studies are inversely associated with incident depression and the onset of subclinical depressive symptoms among adults regardless of global region, gender, age or follow-up period.

Associations between three measures of physical activity and selected influences on physical activity in youth transitioning from elementary to middle school.

Measurement of physical activity is challenging, and objective and subjective methods can be used. The purposes of this study were to apply structural equation modeling in: 1) examining the associations between three distinct measures of physical activity and three factors that are often found to be correlated to physical activity in children, and 2) examining the associations of the combination of three measures with the same correlates in a cohort of youth followed from 5th to 7th grade. A total of 409 children (45% boys) had complete physical activity data derived from accelerometers, self-report by youth, and proxy-report by parents. The potential correlates of physical activity included self-efficacy, physical activity support, and facilities for physical activity. Structural equation models were used to assess the relationship between physical activity and the correlates. The structural equation models examining associations between individual measures of physical activity and selected correlates showed that parent-reported and child self-reported physical activity were associated with parental support for physical activity and self-efficacy. Objectively measured physical activity was associated only with facilities for physical activity. A structural equation model showed that a composite expression of physical activity, based on the inclusion of all three individual measures, was associated with all three correlates of physical activity. In conclusion, combining measures of physical activity from different sources may improve the identification of correlates of physical activity. This information could be used to plan more effective physical activity interventions in children and youth.

The effects of exercise on mood and prefrontal brain responses to emotional scenes in smokers.

The benefits of exercise for smokers attempting to quit are partially dependent on physical activity levels prior to cessation. Mood disturbances can manifest within 30 min of smoking a cigarette and contribute to negative reinforcement of smoking behavior over time, whereas a single bout of aerobic exercise can reduce negative mood states and improve affect on a similar timescale in non-smokers. The acute effects of exercise among non-abstaining smokers immediately after a cigarette are unknown but may have clinical implications for smokers considering cessation. The aim of this study was to examine the concurrent effects of exercise on mood disturbance and prefrontal brain hemodynamic response to emotionally arousing scenes 30 min after smoking a cigarette and to test whether prefrontal brain hemodynamic response was correlated with affective ratings of the scenes. Fifteen cigarette smokers, averaging 47.6 cigarettes/week in the year prior to screening, served as participants. Functional near-infrared spectroscopy was used to measure hemodynamic status over the dorsolateral prefrontal cortex (DLPFC). Participants viewed pleasant, unpleasant, and neutral scenes prior to smoking a cigarette and 30 min later after seated rest or exercise at a preferred intensity. Mood disturbance was assessed by the Profile of Mood States-Brief Form four times: before smoking a cigarette, before and after exercise and rest, and after a post-condition (exercise/rest) exposure to emotionally arousing scenes. Compared to seated rest, cycling after a cigarette reduced mood disturbance (p = =.038) and DLPFC hemodynamic response to unpleasant (p = =.003) and pleasant (p = =.021) scenes relative to neutral scenes. DLPFC hemodynamic response was not related to affective ratings of scenes. We report that cycling for 20 min at a preferred intensity reduces mood disturbances which occur shortly after smoking a cigarette and blunts DLPFC hemodynamic response to emotionally arousing scenes. The findings encourage further investigation of exercise for smokers in the maintenance stage of smoking cessation.

Physical Activity and Anxiety: A Systematic Review and Meta-analysis of Prospective Cohort Studies.

CONTEXT: Anxiety symptoms and disorders are highly prevalent and costly. Prospective studies suggest that physical activity may prevent anxiety development; however, this body of literature has not been reviewed comprehensively. EVIDENCE ACQUISITION: Studies measuring physical activity at baseline and anxiety at a designated follow-up at least 1 year later were located using MEDLINE, PsycINFO, and CINAHL Complete through June 2018. EVIDENCE SYNTHESIS: Data were analyzed July-December 2018. Study quality was assessed using Q-Coh. Among studies of adults, a random-effects meta-analysis was conducted for crude and the most fully adjusted models for three outcomes: self-reported anxiety symptoms, a diagnosis of any anxiety disorder, and a diagnosis of generalized anxiety disorder. As there were few studies with diverse samples and outcome measures, findings were elaborated with a critical narrative review of all studies. Twenty-four studies (median follow-up, 4.75 years) of >80,000 unique individuals were included in the systematic review; thirteen were included in the meta-analyses. Six studies were assessed as low quality, nine as acceptable, and nine as good. From adjusted models, odds of elevated anxiety symptoms (OR=0.8742, 95% CI=0.7731, 0.9886, n=9), any anxiety disorder (OR=0.6626, 95% CI=0.5337, 0.8227, n=3), and generalized anxiety disorder specifically (OR=0.5438, 95% CI=0.3231, 0.9153, n=3) were significantly lower after physical activity exposure. CONCLUSIONS: Available evidence suggests that engaging in physical activity protects against anxiety symptoms and disorders. However, notable challenges in the current evidence base include issues regarding exposure and outcome measures, consistent adjustment for putative confounders, representativeness of samples, and attrition bias, which warrant further research.

Physical activity is indirectly associated with pain in college women through associations with somatization and panic disorder symptoms: a cross-sectional study.

PURPOSE: This study tested whether the severity of somatization, panic, generalized anxiety, and depression symptoms mediated relationships between physical activity and pain using structural equation modeling. METHODS: College women (n = 1036; mean = SD age of 19.7 ± 3.0 years) reported past week physical activity and the presence of persistent pain (≥1 month). The Psychiatric Diagnostic Screening Questionnaire assessed hypothesized mediators of physical activity effects on pain via symptoms of generalized anxiety, panic, major depressive disorder, and somatization disorder. RESULTS: The percentage of the sample screening positive was 15.7% for generalized anxiety, 5.8% for panic, 11.0% for major depressive, and 16.0% for somatization. The hypothesized model had good fit and accounted for a significant amount of variance in pain (9.1%). Direct paths from physical activity to somatization, generalized anxiety, major depressive disorder, and panic disorder were significant. Paths to pain were significant from somatization and panic disorder. The path from physical activity to pain was not direct but indirect and through significant paths to pain from somatization and panic disorder. Each standard deviation increase in physical activity decreased the probability of pain by 11.0% through panic disorder and 10.7% through somatization disorder. CONCLUSIONS: Physical activity is associated with pain indirectly through associations with panic disorder and somatization disorder symptoms in college women.

Temporal Sequencing of Physical Activity Change Constructs within the Transtheoretical Model.

OBJECTIVE: Studies support the Transtheoretical Model's (TTM) ability to describe behavior change processes and guide interventions; however, the temporal sequencing of constructs is less understood. This cohort study tested five sequences to identify TTM construct changes related to physical activity. METHODS: A random sample provided baseline data (n=689; 63% female; M age (SD)=47(17); 37% white), with 401 participants providing 24-month data, at six-month intervals. RESULTS: Structural equation models revealed processes to cognitions to stage (AIC=29313.093, BIC=29514.883, CFI=0.999, RMSEA=0.006, SRMR=0.026); processes to stage to cognitions (AIC=27788.651, BIC=27973.268, CFI=0.978, RMSEA=0.024, SRMR=0.038), self-efficacy/temptations to processes to decisional balance to stage (AIC=13914.771, BIC=14031.169, CFI=0.981, RMSEA=0.018, SRMR=0.034), and stage to processes to cognitions (AIC=22048.324, BIC=22212.986, CFI=0.976, RMSEA=0.026, SRMR=0.029) all fit well. However, cognitions to processes to stage did not fit the data well (AIC=10353.555, BIC=10444.179, CFI=0.937, RMSEA=0.038, SRMR=0.035). CONCLUSIONS: Integrating results revealed a cyclical model so that intervention efforts should focus on processes to change cognitions related to barrier self-efficacy and decisional balance, which then lead to change in stage and then renew focus on the processes.

Physical activity and generalized anxiety disorder: results from The Irish Longitudinal Study on Ageing (TILDA).

Background: Generalized anxiety disorder (GAD) is prevalent and costly. Physical activity (PA) may protect against other mental health disorders, including depression, but its protective effect on GAD remains under-studied in the general population and unstudied among older adults. Therefore, the present study examines associations between meeting World Health Organization PA guidelines (i.e. ≥150 min of moderate PA, ≥75 min of vigorous PA or ≥600MET min of moderate and vigorous PA weekly) and the prevalence of probable GAD and incidence of GAD. Methods: Participants (n = 3950; 56.2% female) aged ≥50 years completed the short-form International Physical Activity Questionnaire and the abbreviated Penn State Worry Questionnaire at baseline and the Composite International Diagnostic Interview - Short Form to clinically assess GAD 2 years later. Prospective analyses included participants without probable GAD at baseline (n = 3236). Results: Prevalence and incidence of GAD were 18.1% (n = 714) and 0.9% (n = 29), respectively. More respondents with GAD were female (72.2% vs 52.7%), aged 50-59 years (51.7% vs 38.7%), had normal waist circumference (52.7% vs 47.8) and smoked (20.4% vs 13.3%; all P <0.05). Meeting PA guidelines was associated with 25% and 63% lower odds of prevalent [odds ratio (OR) = 0.75, 95% confidence interval: 0.64 to 0.88] and incident (OR = 0.37, 0.17 to 0.85) GAD, respectively, in crude models, and 17% and 57% lower odds of prevalent (OR = 0.83, 0.70 to 0.98) and incident (OR = 0.43, 0.19 to 0.99) GAD, respectively, following adjustment for age, sex, waist circumference, social class and smoking. Conclusions: In addition to established physical health benefits of PA, the present findings support the importance of increasing PA at the population-level for mental health.

Yoga Aids Blood Pressure Recovery After Exposure of Forehead to Cold: A Pilot Study.

Context: Hypotension that occurs after a single bout of aerobic exercise also attenuates the vascular response to discrete stressors, an effect that can last for hours. It is unknown whether the hypotensive benefits of traditional exercise extend to alternative forms of mindful exercise, such as yoga, to confer transient protection against neurovascular challenges that increase blood pressure (BP). Objectives: The study intended to examine the effects of acute exercise on neurovascular responses to exposure of the forehead of female yoga practitioners to vasoconstrictive cold (ie, to cold pressor stress). Design: The research team designed a study with 3 conditions (ie, with participants' participation in 3 activities on separate days in a repeated-measures design). Participants were randomly assigned to perform the activities in 1 of 3 orders across successive visits. Participants: Participants were 9 females, 20 to 33 y old, who had regularly practiced Hatha yoga from 6 mo to 12 y before the start of the study. All participants were normotensive at entry to the study and had normal body weights for their heights. Interventions: All participants performed 3 activities: (1) self-directed yoga practice, the intervention; (2) cycling exercise at a self-selected intensity, a positive control; and (3) quiet rest, a negative control. Outcome Measures: Postintervention, participants' foreheads were exposed to cold. Their systolic blood pressures (SBPs), diastolic blood pressures (DBPs), pulse rates, and forearm oxygenation were assessed using near-infrared spectroscopy. Results: Participants' SBPs and DBPs increased during cold pressor stress under all conditions, concurrent with decreased forearm oxygenation. During recovery from the cold, participants' BPs declined to near precold pressor baseline levels after yoga and cycling but remained elevated after quiet rest. Conclusions: The enhanced recovery of BP from cold applied to the forehead after yoga practice or cycling exercise suggests that both types of exercise promote a hypotensive response, which could indicate lowered cardiovascular risk.

Physical Activity and Changes in Adiposity in the Transition from Elementary to Middle School.

OBJECTIVES: This study examined the longitudinal associations of objectively measured physical activity, sedentary behavior, and diet quality with two measures of adiposity and a measure of weight status. METHODS: A total of 658 children from 21 elementary schools (45.1% boys; 40% white, 33% black, 9% Hispanic, and 18% other race/ethnicity) were assessed at least twice in fifth, sixth, and/or seventh grade. Fat mass index (FMI), percent body fat (PBF), and BMI were calculated from body weight, standing and seated heights, and bioelectrical impedance (BIA) measured each year. RESULTS: At follow-up, both FMI and PBF decreased among boys and increased among girls, while BMI increased in both boys and girls. After controlling for race/ethnicity, parent education, and maturity offset at baseline, growth curve analyses showed that moderate-to-vigorous physical activity (MVPA) was significantly and negatively associated with FMI, PBF, and BMI for both boys and girls. After forming tertiles of fifth grade MVPA, least-square means for FMI, PBF, and BMI were examined by grade and gender. For both boys and girls, higher MVPA was associated with lower FMI, PBF, and BMI at all three grade levels. The relationships between sedentary behavior and diet quality and FMI, PBF, and BMI were not consistent for boys or girls. CONCLUSIONS: As boys and girls transitioned from elementary to middle school, children who participated in higher levels of MVPA maintained more favorable levels of two indicators of adiposity and a measure of weight status. These findings support the need for interventions to help children meet current public health guidelines for physical activity.

Functional Disability in Mild Cognitive Impairment: A Systematic Review and Meta-Analysis.

Accumulating evidence suggests that the pre-dementia syndrome mild cognitive impairment (MCI) is characterized by decrements in instrumental activities of daily living (IADL). The current review was a quantitative synthesis of the available literature to objectively characterize IADL disability in MCI while clarifying inconsistencies in findings across studies. It was hypothesized that individuals with MCI would display significantly greater functional impairment relative to cognitively intact controls. Candidate moderators specified a priori included functional assessment approach, MCI subtype, depressive symptoms, and language conducted. Online databases (PubMed/MEDLINE and PsycINFO) and reference lists were searched to identify peer-reviewed publications assessing IADL in MCI compared to normal aging. A total of 151 effect sizes derived from 106 studies met inclusionary criteria (N = 62,260). Random effects models yielded a large overall summary effect size (Hedges' g = 0.76, 95 % confidence interval: 0.68 - 0.83, p < .001) confirmed in multi-level analyses adjusted for nesting of effect sizes within studies (g = 0.78, 95 % confidence interval: 0.69 - 0.87). Functional assessment strategy and MCI subtype were significant moderators of effect size, whereas depressive symptoms and language were not. Results convincingly demonstrate that MCI is associated with significant difficulties in the performance of complex everyday tasks. It appears that functional decline, like cognitive decline, exists on a continuum from healthy aging to dementia onset. Implications for clinical practice and research priorities are discussed.

Effect of Acute Exercise on Fatigue in People with ME/CFS/SEID: A Meta-analysis.

PURPOSE: A prominent symptom of myalgic encephalomyelitis, chronic fatigue syndrome, or systemic exertion intolerance disease (ME/CFS/SEID) is persistent fatigue that is worsened by physical exertion. Here the population effect of a single bout of exercise on fatigue symptoms in people with ME/CFS/SEID was estimated and effect moderators were identified. METHODS: Google Scholar was systematically searched for peer-reviewed articles published between February 1991 and May 2015. Studies were included where people diagnosed with ME/CFS/SEID and matched control participants completed a single bout of exercise and fatigue self-reports were obtained before and after exercise. Fatigue means, standard deviations, and sample sizes were extracted to calculate effect sizes and the 95% confidence interval. Effects were pooled using a random-effects model and corrected for small sample bias to generate mean Δ. Multilevel regression modeling adjusted for nesting of effects within studies. Moderators identified a priori were diagnostic criteria, fibromyalgia comorbidity, exercise factors (intensity, duration, and type), and measurement factors. RESULTS: Seven studies examining 159 people with ME/CFS/SEID met inclusion criteria, and 47 fatigue effects were derived. The mean fatigue effect was Δ = 0.73 (95% confidence interval = 0.24-1.23). Fatigue increases were larger for people with ME/CFS/SEID when fatigue was measured 4 h or more after exercise ended rather than during or immediately after exercise ceased. CONCLUSIONS: This preliminary evidence indicates that acute exercise increases fatigue in people with ME/CFS/SEID more than that in control groups, but effects were heterogeneous between studies. Future studies with no-exercise control groups of people with ME/CFS/SEID are needed to obtain a more precise estimate of the effect of exercise on fatigue in this population.

Classes of Physical Activity and Sedentary Behavior in 5th Grade Children.

OBJECTIVES: We identified classes of physical activity (PA) and sedentary behaviors (SB) in 5th grade children, associated factors, and trajectories of change into 7th grade. METHODS: This study included N = 495 children (221 boys, 274 girls) who participated in the Transitions and Activity Changes in Kids (TRACK) Study. PA was assessed objectively as well as by self-report. Children, parents, and school administrators completed surveys to assess related factors. Latent class analysis, growth modeling, and adjusted multinomial logistic regression procedures were used to classify children based on self-reported PA and SB and examine associated factors. RESULTS: Three classes of behavior were identified: Class 1: Low PA/Low SB; Class 2: Moderate PA/ High SB; and Class 3: High PA/High SB (boys) or Class 3: High PA (girls). Class 3 children had higher levels of self-efficacy (boys), and enjoyment, parental support, and physical activity equipment at home (girls). Class 2 boys and Class 3 girls did not experience decline in PA (accelerometer) over time. CONCLUSIONS: Self-efficacy (boys) and home environment (girls) may play a role in shaping patterns of PA in children. Findings may help to inform future interventions to encourage children to meet national PA guidelines.

Effects of Sprint Interval Cycling on Fatigue, Energy, and Cerebral Oxygenation.

INTRODUCTION: Feelings of fatigue are reduced after a session of continuous exercise of low-to-moderate intensity lasting 20 min or more, but only when feelings of energy are increased. Feelings of fatigue and energy have not been described after fatiguing, high-intensity interval exercise. Cerebral oxygenation has been implicated as a central correlate of fatigability, but it has not been studied concurrent with perceived fatigue during or after exercise. METHODS: Fifteen recreationally active participants (8 women, 7 men) completed bouts of sprint interval cycling (four, 30-s all-out sprints each followed by 4 min of active recovery) and a time- and work-matched bout of constant resistance cycling. Oxygenation (oxygenated hemoglobin [HbO2]) and deoxygenation (deoxygenated hemoglobin [HHb]) in the dorsolateral prefrontal cortex were measured using near-infrared spectroscopy. Fatigue ratings during each sprint and feelings of fatigue and energy during recovery were assessed. RESULTS: Increases in HbO2 and HHb in frontal cortex were greater during sprint cycling than during constant resistance cycling (P = 0.001). Fatigability (decreased power output) increased over successive sprints (P = 0.001). About 95% of the increase in fatigue ratings across sprints (P < 0.001) was accounted for by fatigability and cortical HbO2. Feelings of fatigue were decreased (P < 0.001) and feelings of energy were increased (P < 0.05) across sprint recovery periods but were unchanged during constant resistance cycling. About 85% of the changes in feelings of fatigue or energy during recovery were explained by fatigue ratings across sprints and maximum HbO2 in the cortex during recovery. CONCLUSION: Repeated, high-intensity sprints were fatiguing, but paradoxical reductions in feelings of fatigue and increases in feelings of energy occurred during recovery that were accounted for by ratings of fatigue during exercise and oxygenation in the dorsolateral prefrontal cortex during recovery.

Effects of Resistance Training on Lower-Extremity Muscle Power in Middle-Aged and Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Resistance training (RT) has been investigated as a potential intervention strategy for improving muscle function, but the effects on lower-extremity muscle power in middle-aged and older adults have not been systematically reviewed. OBJECTIVE: The aim of this meta-analysis is to provide a quantitative estimate of the effect of RT on lower-extremity muscle power in middle-aged and older adults and to examine independent moderators of this relationship. METHODS: Randomized controlled trials that examined the effects of RT on either leg press (LP) or knee extension (KE) muscle power in adults aged ≥50 years were included. Data were aggregated with meta-analytic techniques, and multi-level modeling was used to adjust for nesting effects. A total of 52 effects from 12 randomized controlled trials were analyzed with a random-effects model to estimate the effect of RT on lower-extremity muscle power. A multiple-regression analysis was conducted to examine independent moderators of the mean effect. RESULTS: The adjusted aggregated results from all studies indicate that RT has a small-to-moderate effect on lower-extremity muscle power (Hedges' d = 0.34, 95% confidence interval [CI] 0.25-0.43), which translated to 54.90 watts (95 % CI 40.37-69.43). Meta-regression analyses indicated that high-velocity RT was superior to traditional RT (Δ = 0.62 vs. 0.20, respectively) for increasing lower-extremity muscle power. In addition, training volume significantly moderated the effect of RT on muscle power. CONCLUSION: The findings from this meta-analysis indicate that RT is an efficacious intervention strategy for improving LP and KE muscle power in adults aged ≥50 years. Training mode and volume independently moderate the effect of RT on lower-extremity muscle power, and should be considered when prescribing RT exercise for middle-aged and older adults.

Structural Equation Modeling Supports a Moderating Role of Personality in the Relationship Between Physical Activity and Mental Health in College Women.

BACKGROUND: A positive association between physical activity and mental health is well established, particularly for lower symptoms of depression and anxiety among active adults. However, it is unclear whether the association is influenced by personality, which might moderate or otherwise explain the association. In addition, past studies have not confirmed the association using an objective measure of physical activity. OBJECTIVE: Our objective was to examine whether Extraversion and Neuroticism influence the association between mental health and physical activity measured by convergent self-reports and an accelerometer. METHODS: Structural equation modeling was used to test competing models of the relationships between personality, physical activity, and mental health in a sample of female undergraduates. RESULTS: In bivariate analysis, mental health was negatively related to Neuroticism and positively related to Extraversion, self-reported physical activity (which was related only to Extraversion, positively), and objective physical activity (which was related only to Neuroticism, negatively). In structural equation modeling, a 3-way interaction indicated that objective physical activity and mental health were unrelated in extraverts, but related positively in neurotic-introverts and negatively in stable-introverts. CONCLUSIONS: Higher levels of physical activity were associated with better mental health only in neurotic-introverts, who are at higher risk for mental health problems.

Age Moderates the Association of Aerobic Exercise with Initial Learning of an Online Task Requiring Cognitive Control.

The aim of this study was to examine whether people differed in change in performance across the first five blocks of an online flanker task and whether those trajectories of change were associated with self-reported aerobic or resistance exercise frequency according to age. A total of 8752 men and women aged 13-89 completed a lifestyle survey and five 45-s games (each game was a block of ~46 trials) of an online flanker task. Accuracy of the congruent and incongruent flanker stimuli was analyzed using latent class and growth curve modeling adjusting for time between blocks, whether the blocks occurred on the same or different days, education, smoking, sleep, caffeinated coffee and tea use, and Lumosity training status ("free play" or part of a "daily brain workout"). Aerobic and resistance exercise were unrelated to first block accuracies. For the more cognitively demanding incongruent flanker stimuli, aerobic activity was positively related to the linear increase in accuracy [B=0.577%, 95% confidence interval (CI), 0.112 to 1.25 per day above the weekly mean of 2.8 days] and inversely related to the quadratic deceleration of accuracy gains (B=-0.619% CI, -1.117 to -0.121 per day). An interaction of aerobic activity with age indicated that active participants younger than age 45 had a larger linear increase and a smaller quadratic deceleration compared to other participants. Age moderates the association between self-reported aerobic, but not self-reported resistance, exercise and changes in cognitive control that occur with practice during incongruent presentations across five blocks of a 45-s online, flanker task.

Decline in cardiorespiratory fitness and odds of incident sleep complaints.

PURPOSE: To examine longitudinal change in cardiorespiratory fitness and odds of incident sleep problems. METHODS: A cohort of 7368 men and 1155 women, age 20-85 yr, was recruited from the Aerobics Center Longitudinal Study. The cohort did not complain of sleep problems, depression, or anxiety at their first clinic visit. Cardiorespiratory fitness assessed at four clinic visits between 1971 and 2006, each separated by an average of 2-3 yr, was used as a proxy measure of cumulative physical activity exposure. Sleep complaints were made to a physician during follow-up. RESULTS: Across visits, there were 784 incident cases of sleep complaints in men and 207 cases in women. After adjusting for age, time between visits, body mass index, smoking, alcohol use, chronic medical conditions, complaints of depression or anxiety at each visit, and fitness at visit 1, each minute of decline in treadmill endurance (i.e., a decline in cardiorespiratory fitness of approximately 0.5 MET) between the ages of 51 and 56 yr increased the odds of incident sleep complaints by 1.7% (range = 1.0%-2.4%) in men and by 1.3% (range = 0.0%-2.8%) in women. Odds were ∼8% higher per minute decline in people with sleep complaints at visits 2 and 3. CONCLUSIONS: The results indicate that maintenance of cardiorespiratory fitness during middle age, when decline in fitness typically accelerates and risk of sleep problems is elevated, helps protect against the onset of sleep complaints made to a physician.

Personality Correlates of Physical Activity in College Women.

UNLABELLED: Commonly reported relationships of the broad personality traits of extraversion and neuroticism with self-reports of physical activity (PA) have not been elaborated within motivational theory that posits how functioning of the behavioral inhibition (BIS) and activation (BAS) systems can explain or modify the influence of personality on PA. Whether personality predicts physical activity when it is measured objectively has not been established. PURPOSE: The study was aimed to test direct, indirect, and interactive relations between extraversion, neuroticism, BIS and BAS, and PA measured by validated self-report and accelerometry. METHODS: Two samples of female undergraduates completed personality questionnaires. Sample 2 also completed three PA self-reports and wore an accelerometer for 7 d. Factor structure and measurement equivalence of personality measures, structural equivalence of relationships between personality factors, and multivariate prediction of self-reported and objectively measured PA by personality were tested using structural equation modeling. RESULTS: Equivalence between samples for personality models was confirmed. Behavioral activation system predicted self-reported PA. Neuroticism and BIS predicted objectively measured PA. CONCLUSIONS: The relationship between personality and PA may differ according to method used to measure PA. Behavioral inhibition system seems to protect against inactivity among young women high in neuroticism.

Access to environmental resources and physical activity levels of adults in Hawaii.

PURPOSE: Examine associations between physical activity (PA) and spatial accessibility to environmental PA resources in Hawaii. METHODS: Metabolic equivalents (METs) of mild, moderate, and strenuous PA were compared for accessibility with environmental PA resources within a population-based sample of Hawaiian adults (n = 381). Multiple linear regression estimated differences in PA levels for residing further from a PA resource or residing in an area with a greater number of resources. RESULTS: No associations were found in the total sample. Analyses within subsamples stratified by ethnicity revealed that greater spatial accessibility to a PA resource was positively associated with strenuous PA among Caucasians (P = .04) but negatively associated with moderate PA among Native Hawaiians (P = .00). CONCLUSION: The lack of association in the total sample may be a consequence of Hawaii's unique environment. Results of stratified sample analyses are unique, providing groundwork for future examinations within parallel environments and among similar ethnic groups.

Striatal enkephalinergic differences in rats selectively bred for intrinsic running capacity.

UNLABELLED: Rats selectively bred for high- and low-capacity for running on a treadmill (HCR; LCR) also differ in wheel-running behavior, but whether wheel-running can be explained by intrinsic or adaptive brain mechanisms is not as yet understood. It is established that motivation of locomotory behavior is driven by dopaminergic transmission in mesolimbic and mesostriatal systems. However, whether voluntary wheel running is associated with enkephalinergic activity in the ventral striatum is not known. MATERIALS AND METHODS: 40 male (20 HCR and 20 LCR) and 40 female (20 HCR and 20 LCR) rats were randomly assigned to 3 weeks of activity wheel exposure or sedentary conditions without wheel access. After 3 weeks of activity-wheel running, rats were decapitated and brains were extracted. Coronal sections were analyzed utilizing in situ hybridization histochemistry for enkephalin (ENK) mRNA in the ventral striatum. RESULTS: HCR rats expressed less ENK than LCR rats in the nucleus accumbens among females (p<0.01) and in the olfactory tubercle among both females (p<0.05) and males (p<0.05). There was no effect of wheel running on ENK mRNA expression. CONCLUSION: Line differences in ENK expression in the olfactory tubercle, and possibly the nucleus accumbens, partly explain divergent wheel-running behavior. The lower striatal ENK in the HCR line is consistent with enhanced dopaminergic tone, which may explain the increased motivation for wheel running observed in the HCR line.