24-hr Day Research Articles

Environmental factors associated with Escherichia coli concentration at freshwater beaches on Lake Winnipeg, Manitoba, Canada

At many public beaches, routine monitoring of beach water quality using fecal indicator bacteria is conducted to evaluate the risk of recreational water illness. Results from water sample analysis can take over 24-hr, which may no longer accurately reflect current water quality conditions. This study aimed to assess which combination of environmental factors best predicts fecal contamination (E. coli) levels at two of the most popular beaches on Lake Winnipeg, Manitoba (Gimli and Grand Beach), by linking water quality data and publicly available environmental data from 2007 to 2021. We developed separate mixed effects models for each beach for two outcomes, linear (continuous log-transformed E. coli concentration) and categorical (200 CFU/100 ml threshold), to explore differences in the predictors of E. coli concentrations and exceedances of the provincial health risk threshold, respectively. We used a Directed Acyclic Graph to choose which predictor variables to include in the models. For both beaches, we identified clustering of the E. coli outcomes by year, suggesting year-specific variation. We also determined that extreme weather days, with higher levels of rainfall in the preceding 48-hr, previous day average air temperature, and previous day E. coli concentration could result in a higher probability of E. coli threshold exceedances or higher concentrations in the water bodies. In Grand Beach, we identified that days with lower average UV levels in the previous 24-hr and antecedent dry days could result in a higher probability of E. coli threshold exceedances or higher concentrations. The findings can inform possible trends in other freshwater settings and be used to help develop real-time recreational water quality predictive models to allow more accurate beach management decisions and warrant enhancement of beach monitoring programs for extreme weather events as part of the climate change preparedness efforts.

Validity of the German Version of Daily Activity Behaviours Questionnaire Among Older Adults.

Time spent in physical activity, sedentary behavior, and sleep collectively impact health of older adults. There is a need for valid self-reported methods for the assessment of movement behaviors across the entire 24-hr day. The aim of this study was to explore the validity of the German version of Daily Activity Behaviours Questionnaire (DABQ), the "Schlaf- und Aktivitätsfragebogen (SAF)," among older adults. Participants were asked to wear activity monitor (activPAL) for a period of 8days and to complete the German version of DABQ. Seventy-seven participants (45 females; 68 ± 5years of age) completed the protocol. Spearman's correlation coefficients between DABQ and activPAL estimates for time spent in sleep, sedentary behavior, light physical activity, and moderate to vigorous physical activity were .69, .35, .24, and .52, respectively. The German version of the DABQ showed satisfactory validity to be used in epidemiological research and population surveillance among older adults.

Effects of Nondipping Blood Pressure Changes: A Nephrologist Prospect.

Blood pressure (BP) variations depend on various internal, environmental, and behavioral factors. BP fluctuations occur both in normotensive and hypertensive people. Although it fluctuates over the 24-hr day and night, the morning BP increases after waking up and declines throughout sleep.It is typical for BP to decrease by 10% to 20%, while sleeping, known as dipping BP. However, if there is no decrease in nighttime mean systolic BP or a drop of less than 10 mmHg, it is called nondipping BP. Conversely, reverse dipping BP means an increase in mean systolic BP instead of a drop during the night. Reverse dipping is observed in hypertension (HTN), diabetes mellitus (DM), chronic kidney disease (CKD), and obstructive sleep apnea (OSA) syndrome. The introduction of ambulatory BP monitoring (ABPM) led to the emergence of identifying normal and elevated BP patterns. Non-dipping BP increases the risk of cardiovascular system (CVS) complications such as left ventricular hypertrophy, proteinuria, glomerular filtration rate (GFR) reduction, and CKD progression.A loss or blunting of the normal BP profile is recognized as a deleterious variant, and restoring abnormal BP patterns has been reported to significantly impact end-organ damage, morbidity, and mortality. In this non-systematic clinically-oriented, comprehensive review, we aim to update the BP variables and the pathophysiology of nondipping BP and point out the areas which need more investigation from a nephrology perspective because the nondipping BP increases the risk of proteinuria, GFR reduction, and CKD progression. A literature search of PubMed, Google, EMBASE, and Google Scholar was conducted. Checks of selected papers and relevant reviews complemented the electronic search. With improved BP measurement methods, the physiology of BP profile variations is readily detectable during the day and night. A nondipping BP profile is a distinct BP pattern that may have significant end-organ damage effects and therapeutic importance for nephrologists. The pathophysiology of the nondipping BP variant must be clarified to prevent complications, and further investigations are required. Furthermore, there is debate about the best BP index to utilize: systolic BP, diastolic BP, mean arterial pressure, or a mixture of all. All these areas are important and need new research projects.

Obesity elicits a sex‐specific attenuation of the daily rhythm in ventilation in mice chronically fed a high‐fat diet

To efficiently deal with changes in nutrient availability across the 24‐hr day, animals have evolved daily rhythms in energy metabolism and, consequently, a daily rhythm in ventilation to mediate metabolic gas exchange. Daily ventilatory rhythms have been implicated in a variety of respiratory diseases such as sleep apnea, due to time‐specific occurrence of symptoms. However, it is unknown how obese physiology and intermittent hypoxia (IH), two hallmarks of sleep apnea, influence the daily rhythm in ventilation. Here, we use a dietary mouse model of obesity to determine the extent to which ventilation rhythms are influenced by obese physiology and IH. Using whole‐body plethysmography, we found that obese mice chronically‐fed a high‐fat diet exhibit a dampened minute ventilation rhythm and decreased mean ventilation during the night‐time. The obesity‐associated reduction in minute ventilation was sex‐specific and resulted in part from a failure of female mice to increase minute ventilation in proportion to weight gain. Moreover, we found that 5 days of daytime IH exposure minimally affected the daily rhythm in minute ventilation. We conclude that the daily rhythm in minute ventilation is attenuated by obesity in a sex‐specific manner but largely unaffected by intermittent hypoxia. Taken together, these results have clinical implications for obesity‐associated respiratory diseases such as obstructive sleep apnea.

Surf Scoters use deeper offshore waters during nocturnal resting periods in the Salish Sea of Washington and British Columbia

Abstract Diurnally biased monitoring and research dominate our ecological understanding and guide conservation and management decisions regarding important indicator sea duck species, such as Surf Scoters (Melanitta perspicillata). Advances in telemetry technology are improving our ability to track wildlife across the entire 24-hr day. Using location data derived from birds with surgically implanted satellite transmitters and habitat layers within a GIS (geographic information system), we analyzed Surf Scoter location data to (1) estimate movement distances between diurnal and nocturnal sites, (2) assess differences in environmental conditions at diurnal and nocturnal use locations, (3) evaluate the environmental conditions influencing nocturnal habitat selection, and (4) develop a predictive model to estimate likely nocturnal resting areas across the Salish Sea, which is composed of the inland marine waters of British Columbia, Canada, and Washington State. Surf Scoters in the Salish Sea traveled an average of 4,287 m between diurnal and nocturnal habitats, but distances varied regionally. We found that distance to shore, water depth, tidal current, and vessel traffic influenced nocturnal habitat use. Surf Scoter nocturnal use sites were characterized by greater distances from shore and deeper water than diurnal locations, although scoters avoided areas with strong tidal currents and heavy shipping traffic at night. The Salish Sea is experiencing increased ship traffic from multiple U.S. and Canadian ports. Oil tanker and shipping container vessel traffic pose a potential threat to nocturnal scoter flocks aggregating in deeper water adjacent to and sometimes overlapping with shipping lanes in narrow, glacial-carved channels of the Salish Sea. Current oil spill response plans in Washington State waters utilize diurnal distribution data, lacking important nocturnal use data. Our findings provide critical nocturnal habitat use information that can improve oil spill response policy and highlight the importance of elucidating nocturnal ecology for marine vertebrate species.

Outdoor daylight exposure and longer sleep promote wellbeing under COVID-19 mandated restrictions.

SummaryLight is an important regulator of daily human physiology in providing time‐of‐day information for the circadian clock to stay synchronised with the 24‐hr day. The coronavirus disease 2019 (COVID‐19) pandemic led to social restrictions in many countries to prevent virus spreading, restrictions that dramatically altered daily routines and limited outdoor daylight exposure. We previously reported that sleep duration increased, social jetlag decreased, and mid‐sleep times delayed during social restrictions (Global Chrono Corona Survey, N = 7,517). In the present study, we investigated in the same dataset changes in wellbeing and their link to outdoor daylight exposure, and sleep–wake behaviour. In social restrictions, median values of sleep quality, quality of life, physical activity and productivity deteriorated, while screen time increased, and outdoor daylight exposure was reduced by ~58%. Yet, many survey participants also reported no changes or even improvements. Larger reductions in outdoor daylight exposure were linked to deteriorations in wellbeing and delayed mid‐sleep times. Notably, sleep duration was not associated with outdoor daylight exposure loss. Longer sleep and decreased alarm‐clock use dose‐dependently correlated with changes in sleep quality and quality of life. Regression analysis for each wellbeing aspect showed that a model with six predictors including both levels and their deltas of outdoor daylight exposure, sleep duration and mid‐sleep timing explained 5%–10% of the variance in changes of wellbeing scores (except for productivity). As exposure to daylight may extenuate the negative effects of social restriction and prevent sleep disruption, public strategies during pandemics should actively foster spending more daytime outdoors.

Fragmented day-night cycle induces period lengthening, lowered anxiety, and anhedonia in male mice

Light exposure at night disrupts circadian-regulated biological functions, including mood. However, the consequence of fragmenting the night period and distributing it across the 24-hr period is less understood. Here we show that fragmenting an 8 -h and 6 -h night into equally distributed 2 -h periods throughout the 24-hr day results in period lengthening of the circadian rhythm in mice. Furthermore, mice exhibited less anxiety, which indicates increased risk-taking behavior, and a lack of pleasure-seeking, known as anhedonia. The successive alley and open field tests were used to assess anxiety, while the sucrose preference test was used to assess anhedonia. Analysis of depressive-like behaviors with the forced swim and tail suspension tests were not observed. After two weeks in 12 h light – 12 h dark, mice exposed to the fragmented night recovered and exhibited normal behaviors for both anxiety and anhedonia. Our results are congruent with published studies that describe the detrimental effects of constant light conditions on circadian rhythms and mood. These findings unveil the negative impact that fragmenting the day-night cycle has on circadian rhythms and mood.

Simulated driving performance in healthy adults after night-time administration of 20mg tasimelteon.

SummaryAn impairment in next day driving performance has been reported for almost every drug currently United States Food and Drug Administration (FDA) approved for improvement of sleep in chronic and transient insomnia. Tasimelteon, a melatonin receptor agonist, demonstrated significant improvements in night‐time sleep, daytime naps, and sleep timing in non‐24‐hr sleep–wake disorder (Non‐24) by entraining these patients to a 24‐hr day as measured by melatonin and cortisol rhythms. Given this new mechanism of action of entraining the biological clock, we conducted a study to evaluate the potential effect tasimelteon may have on the ability to operate a motor vehicle. The study was conducted in 48 healthy adult subjects using a randomised, double‐blind, placebo and active (zopiclone 7.5 mg) controlled study with a 3‐period cross‐over design. Driving performance was assessed by measuring standard deviation of lateral position (SDLP) using the validated Cognitive Research Corporation Driving Simulator‐MiniSim. The difference in least square mean SDLP for tasimelteon was 1.22 cm reflecting a non‐significant increase in SDLP change from placebo (p = .1119). In contrast, treatment with the active control, zopiclone 7.5 mg, was associated with a meaningful and significant increase in SDLP, change from placebo for zopiclone was 4.14 cm (p < .0001). The lack of clinically meaningful and statistically significant finding with tasimelteon was further supported by the symmetry analysis, which showed the distribution of within‐subject differences between tasimelteon and placebo was symmetric about zero. At the FDA‐approved 20 mg dose to treat Non‐24, tasimelteon did not impair next‐day driving performance compared to placebo in adult healthy volunteers.

1193-P: Investigating the Role of Intestinal L-Cell Secretagogin in Circadian GLP-1 Secretion in a Mouse Model of Type 2 Diabetes

The intestinal L-cell hormone Glucagon-like Peptide-1 (GLP-1) increases glucose-dependent insulin secretion and is thus used in the treatment of T2D. GLP-1 secretion from the L-cell exhibits a circadian pattern in rodents and varies by time-of-day in humans. We have shown that KD of the SNARE-regulatory protein, secretagogin (SCGN) prevents time-dependent GLP-1 release. SCGN KD in ß-cells also decreases insulin secretion and SCGN levels are reduced in T2D islets. We thus hypothesized that SCGN is decreased in the L-cell in T2D, causing alterations in the physiological pattern of GLP-1 secretion. High-fat diet, low-dose streptozotocin (HFD-STZ) mice, a model of T2D, exhibited increased fasting glucose (5.5 vs. 15.6 mmol/L; p&amp;lt;0.001) and decreased ß-cell area (by 75%, p&amp;lt;0.001). Unexpectedly, oral glucose tolerance tests conducted in 4-hour intervals through the 24-hr day showed that HFD-STZ mice exhibit a 10x increase in GLP-1 responses (400 vs. 4000 pg/ml*60 min, p&amp;lt;0.001) and exhibit an anti-phasic rhythm to controls. Basal GLP-1 levels remained unchanged between HFD-STZ and controls. Unexpectedly, insulin responses were not reduced in HFD-STZ mice, suggesting that increased GLP-1 levels could act as a compensatory mechanism. HFD-STZ mice also exhibited hyperglucagonemia compared to control, with increased glucagon secretion across timepoints following glucose administration (–243 vs. 800 pg/ml*60 min, p&amp;lt;0.001). RT-qPCR of intestinal mucosa showed an anti-phasic Scgn rhythm in the HFD-STZ model, with a 1.5-fold increase in average expression across timepoints (p&amp;lt;0.05), which could explain the drastically increased GLP-1 secretion. These data show that GLP-1 secretion is both increased and arrhythmic in a murine model of T2D, and that this occurs in association with an unanticipated increase in Scgn expression. Further investigation into the role of SGCN in the L-cell may serve as an avenue for therapeutics aimed at increasing endogenous GLP-1 release. Disclosure A. Biancolin: None. P. L. Brubaker: None. Funding Canadian Institutes of Health Research (PJT-15308)

Cinnamon effects on blood pressure and metabolic profile: A double-blind, randomized, placebo-controlled trial in patients with stage 1 hypertension.

Cinnamon effect on blood pressure remains controversial. The present pilot study assessed cinnamon effect on blood pressure, and metabolic profile of stage 1 hypertension patients (S1HTN). This double-blind placebo-controlled randomized trial was conducted between June and October 2019, in Mashhad, Iran. Study inclusion criteria comprised S1HTN diagnosis, based on 24-hour ambulatory blood pressure monitoring (ABPM). Subjects were randomly assigned to two groups: cinnamon group (capsule, 1500 mg/day, 90 days) and placebo group. On days 0 and 90, ABPM derived systolic and diastolic blood pressure (SBP and DBP, respectively), blood lipid profile, and fasting blood sugar (FBS) were recorded. The two groups did not differ significantly regarding vascular risk factors, educational status, lipid profile and blood pressure at baseline, except for lower HDL-c in cinnamon group (p=0.03). On day 90, there was no significant difference between two study groups for lipid profile and blood pressure. A statistically significant decrease in mean 24-hr SBP and mean day SBP was observed in the cinnamon group, while mean night SBP and mean night DBP were decreased significantly in the placebo group after 90 days. A statistically significant decrease in mean change of day value of SBP was found in the cinnamon group, compared to the placebo. On day 90, FBS remained practically unchanged but a significant increase in HDL-c (5.8 unit; p=0.01) and a significant decrease in LDL-c levels (17.7 unit; p=0.009) were observed in the cinnamon group compared to placebo group. Cinnamon caused a statistically significant decrease in mean ambulatory SBP but in a clinically moderate way, and lipid profile was significantly improved. Therefore, cinnamon might be considered a complementary treatment in subjects with S1HTN.

Circadian rhythms and the HPA axis: A systems view.

The circadian timing system comprises a network of time-keeping clocks distributed across a living host whose responsibility is to allocate resources and distribute functions temporally to optimize fitness. The molecular structures generating these rhythms have evolved to accommodate the rotation of the earth in an attempt to primarily match the light/dark periods during the 24-hr day. To maintain synchrony of timing across and within tissues, information from the central clock, located in the suprachiasmatic nucleus, is conveyed using systemic signals. Leading among those signals are endocrine hormones, and while the hypothalamic-pituitary-adrenal axis through the release of glucocorticoids is a major pacesetter. Interestingly, the fundamental units at the molecular and physiological scales that generate local and systemic signals share critical structural properties. These properties enable time-keeping systems to generate rhythmic signals and allow them to adopt specific properties as they interact with each other and the external environment. The purpose of this review is to provide a broad overview of these structures, discuss their functional characteristics, and describe some of their fundamental properties as these related to health and disease. This article is categorized under: Immune System Diseases > Computational Models Immune System Diseases > Biomedical Engineering.

Circadian Melatonin Secretion In Obese Adolescents With Or Without Obstructive Sleep Apnea

Objective — To compare melatonin levels in saliva during a 24-hr day in order to identify the specificities of circadian melatonin secretion in obese adolescents with or without obstructive sleep apnea (OSA). Material and Methods — We examined 18 obese adolescents with OSA, 12 obese adolescents without OSA, and 15 healthy adolescents with a normal body weight, from whom saliva was sampled four time during the 24-hr day. Polysomnography was used to diagnose OSA. Saliva samples (n=180) were subjected to enzyme-linked immunosorbent assay. Results — Obese adolescents with OSA had higher evening melatonin levels than obese adolescents without OSA. For example, this indicator in OSA patients was 5.3 times higher than in participants without OSA, who had the lowest evening melatonin level among all groups. In both obese groups, nighttime melatonin levels were significantly lower than in the control group. A positive correlation was detected between the levels of morning and afternoon melatonin and body mass index only in obese adolescents without OSA (r=0.58; p=0.03 and r=0.68; p=0.01, respectively). It was found that evening melatonin correlated with minimum blood oxygen saturation (SaO2) in the entire sample of adolescents with OSA (r=-0.69; p=0.008), and it also correlated with time with SaO2 &lt;90% in the group with clinical manifestations of OSA (r=0.76; p=0.003). Nighttime melatonin levels negatively correlated with the minimum SaO2 value solely in the group with clinical manifestations of OSA (r=-0.58; p=0.035). Conclusion — The circadian melatonin secretion in obese adolescents differed, depending on the presence or absence of OSA, and correlated with the level of oxygen desaturation in OSA patients, to a greater extent – in the presence of clinical manifestations.

Analysis of Transportation Users’ Preferences and Attitudes for Identifying Micro-Level Determinants of Transportation Network Companies’ (TNCs) Growth

Over the last decade, the popularity of Transportation Network Companies (TNCs) as a mode of travel has been increasing at a steady pace. This trend highlights the importance of identifying the determinants that influence transportation users to adopt TNCs as a preferred mode choice and the impacts of such preferences on their travel patterns and transportation network operation. This paper reports on a recent study undertaken in Birmingham, AL aiming at understanding and documenting the factors that influence transportation users to select TNCs (such as Uber/Lyft) for completing typical day trips. In doing so, a travel diary questionnaire survey was developed in accordance with the Institute of Transportation Engineers (ITE) Manual on Transportation Engineering Studies using the Qualtrics Research Core platform. The questionnaire was used to survey over 450 transportation users in the Birmingham Metro area. The survey participants provided detailed trip information for a typical 24-hr day along with demographic data and travel preference information. The survey responses provide high-resolution micro-level indicators of travel preferences and behaviors in a TNC-served area, which is a much-needed type of information for researchers and transportation planning agencies.

The Effects of Short-Term and Very Short-Term Particulate Matter Exposure on Asthma-Related Hospital Visits: National Health Insurance Data

PurposeThe purpose of this study was to investigate the effects of short-term and very short-term exposure to particulate matter (PM) exceeding the daily average environmental standards for Korea (≤100 µg/m3 for PM10 and ≤50 µg/m3 for PM2.5) on on asthma-related hospital visits.Materials and MethodsThis was a population-based, case-crossover study using National Health Insurance and air pollution data between January 1, 2014 and December 31, 2016. The event day was defined as a day when PM exceeded the daily average environmental standard (short-term exposure) or daily average environmental standard for 2 hours (very short-term exposure). The control day was defined as the same day of the week at 1 week prior to the event day.ResultsCompared with control days, asthma-related hospital visits on the 24-hr event days and 2-hr event days increased by 4.10% and 3.45% for PM10 and 5.66% and 3.74% for PM2.5, respectively. Asthma-related hospital visits increased from the 24-hr event day for PM10 to 4 days after the event day, peaking on the third day after the event day (1.26, 95% confidence interval, 1.22–1.30). Hospitalizations also increased on the third day after the event. While there was a difference in magnitude, PM2.5 exposure showed similar trends to PM10 exposure.ConclusionWe found a significant association between short-term and very short-term PM exposure exceeding the current daily average environmental standards of Korea and asthma-related hospital visits. These results are expected to aid in establishing appropriate environmental standards and relevant policies for PM.

Diel and infradian (7-day) activity rhythms in Mexican spider monkeys (Ateles geoffroyi) kept with and without visitor contact.

Diel activity rhythms in mammals are regulated by an endogenous (circadian) timing system which is synchronized by environmental 24-hr periodicities called zeitgebers. Additional direct responses to stochastic environmental factors ensure the fine-tuning to the actual situation and may mask the circadian time course. Following an observational study on behavioral effects of visitor activities in a group of spider monkeys (Ateles geoffroyi) kept free-ranging on a small island of Lake Catemaco, Veracruz, Mexico, we analyzed the effect of weekly varying numbers of visiting tourist boats on the monkeys' diel activity rhythm. With small accelerometer-data logger devices we recorded the monkeys' locomotor activity continuously for several months each. Then we compared the data with those from spider monkeys living without tourist contact. Neither the duration of the monkeys' activity time (α) nor its phase relationship to the 24-hr solar day did change on different weekdays in either site. However, their activity level showed a clear 7-day rhythm. The monkeys of the tourist site showed highest activity on Saturday and Sunday, when the frequency of visiting tourist boats was highest, whereas those of the non-tourist site were least active on Sunday and Monday, when human activities were lowest there. While the monkeys of the non-tourist site usually displayed a distinct bimodal activity pattern peaking in the morning and late afternoon, the pattern in those of the tourist site mostly lacked a morning peak and varied more over time. Based on our results, we suggest that circadian entrainment is not involved in the differences between the diel activity rhythms of the spider monkeys from the two keeping sites and the differing 7-day variation in their activity level. Rather, these differences seemingly reflect direct responses to the differing human activities and thus may correspond to circadian masking effects.

Daytime Acute Non-Visual Alerting Response in Brain Activity Occurs as a Result of Short- and Long-Wavelengths of Light

Abstract. Very recent preliminary findings concerning the alerting capacities of light stimulus with long-wavelengths suggest the existence of neural pathways other than melatonin suppression that trigger the nonvisual response. Though the nonvisual effects of light during the daytime have not been investigated thoroughly, they are definitely worth investigating. The purpose of the present study is to enrich existing evidence by describing how quantitative electroencephalography (EEG) signal analysis can give insight into the measurement of the acute nonvisual response observed in brain states generated during daytime exposure to light (when melatonin secretion is negligible). EEG changes were assessed in 19 subjects during the daytime while being exposed to both short- (blue, 72 μW/cm2) and long-wavelength (red, 18 μW/cm2) radiation. We showed that artificial light stimulus as low as 40 lux decreases the synchronization in the upper theta, lower alpha, and upper alpha EEG activity spectrum. The direction of change was consistent with an increased level of alertness. We can conclude that EEG analysis is an indicator of the acute nonvisual response to daytime light. Surprisingly, the response was more spread over the scalp during exposure to red light than to blue light. According to our study, the response to long-wavelength stimulus that inhibits sleepiness, thereby inducing alertness, also takes place at the bright part of the 24-hr day when human beings are naturally predisposed to be exposed to a high level of sunlight: between 12 and 4 PM. The absorption spectrum of the nonvisual system seems to have different characteristics than was previously suspected: it is not dominated by the short-wavelengths, but involves long-wavelengths. Since we observed the predominance of the red-light alerting effect over the blue-light in this experiment, we conclude that more than one mechanism, beyond the melatonin pathway, must be involved.

Does compliance with healthy lifestyle behaviours cluster within individuals in Australian primary school-aged children?

The 3 "movement behaviours" of sleep, screen time, and physical activity are associated with a wide range of health outcomes in children. This study examined whether these behaviours cluster together within individuals in Australian primary school children. Three datasets including 4,449 9- to 11-year-old children were interrogated-(a) Obesity Prevention and Lifestyle (OPAL), (b) the International Study of Children, Obesity, Lifestyle and Environment (ISCOLE), and (c) the National Children's Nutrition and Physical Activity Survey (NCNPAS). The surveys measured movement behaviours using different instruments (accelerometry, use of time recall, and questionnaires) and different operationalizations of compliance. Observed frequencies of compliance with various combinations of guidelines were compared with expected frequencies based on the assumption of independence, using chi-square tests. Compliance with the sleep guidelines was relatively high (72%, 75%, and 79% in the OPAL, ISCOLE, and NCNPAS datasets, respectively), and compliance with the screen (18%, 35%, and 22%) and physical activity (33%, 57%, and 87%) guidelines was generally lower. Against expectation, there was no evidence of clustering in any of the datasets (p>.99). Compliance with movement behaviour guidelines does not cluster within individuals in 9- to 11-year-old Australian children. It may be unlikely that fostering compliance with one guideline will have a flow-on effect to the others. Temporal trade-offs (i.e., the need to choose one movement behaviour above another) in the 24-hr day may contribute to the lack of clustering.

0390 MEASURING ACTIVITY BY ACTIGRAPHY - ARE WE USING THE RIGHT METHODS?

Actigraphy is commonly used in research to provide an objective measure of sleep. Many attempts to evaluate activity using this measure have been undertaken. These tend to involve day/night activity averages which disregards the variability of the hour-by-hour data and variability. To our knowledge, there have been no attempts to aggregate minute-by-minute activity data into hour-by-hour bins which may provide for a better description of any activity changes across the diurnal day. The present analysis focuses on this data aggregation approach. 15 patients (Mean Age=42.9 ± 10.4; f=12) with chronic pain (non-malignant neck or back pain) who received 8-session CBT-I were evaluated by 7-day actigraphy at baseline and post-treatment (only 10 subjects completed actigraphy at both time-points). Daytime activity averages were computed for baseline and post-tx. Daytime activity averages were evaluated using paired sample t-test. Hour-by-hour activity averages were computed for an average 24-hr period using activity count from minute-by-minute epochs over the 7-days. Mixed models were utilized to evaluate the difference between baseline to post-tx (phase) over the 24-hr period (time). Model included main effect for phase and time along with a phase*time interaction. Weekly activity averages showed no difference in average activity throughout the day between baseline and post-tx (Baseline Activity=376, Post-tx Activity=408.6, p=0.26). However, mixed models assessing the daily activity hour-by-hour revealed a significant main effect for time-of-day (p<0.001) and for phase (p=0.001). While the phase*time-of-day was not significant (p=0.25), descriptive data suggest marked improvement post CBT-I especially in the morning (6-11AM). Utilizing daily activity averages may result in a failure to resolve findings that are evident when assessing activity on an hour-by-hour basis. Further, arraying data in this manner may allow for an appreciation of how activity patterns across the diurnal phase of the 24-hr day. Supported by: NINR NR5R21NR009080-02.

Physical Activity, Inactivity and Health During Youth-2016.

2016 has been an exciting year for research in physical activity, inactivity and health. Recognition of the importance of all physical behaviors (physical activity, sedentary time and sleep) across the 24-hr day continues to grow. Notable advances have included: applications of recent methodological innovations that account for the codependence of the behaviors in the finite 24-hr period showing that the balance of these behaviors is associated with health; methodological innovations focusing on the classification of behaviors and/or quantification of the 24-hr diurnal activity pattern; and a series of systematic reviews that helped provide the evidence base for the release of the innovative 24-hr movement guidelines earlier this year. This commentary focuses on just two of these papers: the first by Goldsmith and colleagues who demonstrate a new statistical method that exploits the time series nature of accelerometer data facilitating new insights into time-specific determinants of children's activity patterns and associations with health; the second by Tremblay and colleagues who describe the evidence base for associations between each physical behavior and children's health, the emerging evidence base for associations between the balance of behaviors and health, and development of the world's first 24-hr movement guidelines.

Physical Activity Measurement by Accelerometry Among Older Malay Adults Living in Semi-Rural Areas-A Feasibility Study.

We evaluated feasibility of physical activity measurement by accelerometry among older Malay adults living in semi-rural areas in Malaysia. Results showed that 95% of 146 participants (aged [SD] 67.6 [6.4] years) were compliant in wearing the accelerometer for at least five days. Fifteen participants were asked for re-wear the accelerometer because they did not have enough valid days during the first assessment. Participants wore the accelerometer an average of 15.3 hr in a 24-hr day, with 6.5 (1.2) valid wear days. No significant difference in valid wear day and time was found between men and women. Participants who are single provide more valid wear days compared with married participants (p < .05), and participants with higher levels of education provide longer periods of accelerometer wearing hours (p < .01). Eighty-seven percent of participants reported 'no issues' with wearing the meter. This study suggests that accelerometry is a feasible method to assess the physical activity level among older Malay adults living in semi-rural areas.