What's Your Poison? Is Sitting Always Health Hindering and Moving Always Health Promoting?

The clear public messaging from international health authorities is that individuals should "sit less and move more." While it is acknowledged that this guidance needs to be tailored to the age of people and also to their health, and abilities, the guidance is not tailored to their current level of physical behaviors. This opinion piece aims to highlight that although people with excessive sitting and insufficient moderate-to-vigorous physical activity should sit more and move less, for other people their health would be promoted by sitting more and moving less. Thus, physical behaviors are not always "poison" or "medicine," but rather the health impact of changes in physical behaviors depends on people's initial levels. Policy, research, and practice implications of this realization are presented. Only tailoring messaging to age and health status could be far from optimal for people with very different current levels of physical behaviors. Policy, research, and practice will be enhanced when the potential for physical behaviors to be either health hindering or health promoting is adequately considered.

The Goldilocks Day for healthy adiposity measures among children and adolescents.

Background: The optimal balance of time spent on daily movement behaviors ("The Goldilocks Day") associated with childhood obesity remains unknown. Objective: To estimate the optimal durations of sleep, sedentary behavior (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MPVA) associated with excess adiposity in a paediatric population. Methods: Accelerometer-measured 24-h movement behaviors were obtained from 659 Czech children and adolescents (8-18-year-olds). Adiposity indicators were body mass index z-score, fat mass percentage, fat-free mass index, and visceral adipose tissue. Excess adiposity was defined as exceeding the 85th percentile for an adiposity indicator. Compositional regression analyses were used investigate the associations between movement behaviors and adiposity indicators and estimating "The Goldilocks Day." Results: The movement behavior composition was associated with visceral adipose tissue (Fdf1 = 3,df2 = 317 = 3.672, p = 0.013) and fat mass percentage (Fdf1 = 3,df2 = 289 = 2.733, p = 0.044) among children and adolescents. The Goldilocks Day consisted of 8.5 h of sleep, 10.8 h of SB, 3.9 h of LPA, and 0.8 h of MVPA among children and 7.5 h of sleep, 12.4 h of SB, 3.6 h of LPA, and 0.5 h of MVPA among adolescents. Conclusion: Optimizing the time spent sleeping, and in sedentary and physical activities appears to be important in the prevention of excess adiposity.

Your best day: An interactive app to translate how time reallocations within a 24-hour day are associated with health measures.

Reallocations of time between daily activities such as sleep, sedentary behavior and physical activity are differentially associated with markers of physical, mental and social health. An individual's most desirable allocation of time may differ depending on which outcomes they value most, with these outcomes potentially competing with each other for reallocations. We aimed to develop an interactive app that translates how self-selected time reallocations are associated with multiple health measures. We used data from the Australian Child Health CheckPoint study (n = 1685, 48% female, 11-12 y), with time spent in daily activities derived from a validated 24-h recall instrument, %body fat from bioelectric impedance, psychosocial health from the Pediatric Quality of Life Inventory and academic performance (writing) from national standardized tests. We created a user-interface to the compositional isotemporal substitution model with interactive sliders that can be manipulated to self-select time reallocations between activities. The time-use composition was significantly associated with body fat percentage (F = 2.66, P < .001), psychosocial health (F = 4.02, P < .001), and academic performance (F = 2.76, P < .001). Dragging the sliders on the app shows how self-selected time reallocations are associated with the health measures. For example, reallocating 60 minutes from screen time to physical activity was associated with -0.8 [95% CI -1.0 to -0.5] %body fat, +1.9 [1.4 to 2.5] psychosocial score and +4.5 [1.8 to 7.2] academic performance. Our app allows the health associations of time reallocations to be compared against each other. Interactive interfaces provide flexibility in selecting which time reallocations to investigate, and may transform how research findings are disseminated.

The Use of Time Flow Analysis to Describe Changes in Physical Ergonomic Work Behaviours Following a Cluster-Randomized Controlled Participatory Ergonomic Intervention.

AIM: Evaluations of participatory ergonomic interventions are often challenging as these types of interventions are tailored to the context and need of the workplace in which they are implemented. We aimed to describe how time flow analysis can be used to describe changes in work behaviours following a participatory ergonomic intervention. METHOD: This study was based on data from a two-arm cluster-randomized controlled trial with 29 childcare institutions and 116 workers (intervention: n = 60, control: n = 56). Physical behaviours at work were technically measured at baseline and 4-month follow-up. Physical behaviours were expressed in terms of relative work time spent forward bending of the back ≥30°, kneeling, active (i.e. walking, stair climbing and running) and sedentary. Average time flow from baseline to follow-up were calculated for both groups to investigate if work time was allocated differently at follow-up. RESULTS: A total of 116 workers (60 in the intervention and 56 in the control group) had valid accelerometer at baseline and follow-up. The largest group difference in time flowing from baseline to follow-up was observed for forward bending of the back and time spent kneeling. Compared to the control, the intervention group had less time flowing from forward bending of the back to kneeling (intervention: +11 min day, control: +16 min day) and more time flowing from kneeling to sedentary behaviours (intervention: +15 min day, control: +10 min day). CONCLUSION: The results of this study showed that time flow analysis can be used to reveal changes in work time-use following a participatory ergonomic intervention. For example, the analysis revealed that the intervention group had replaced more work time spent kneeling with sedentary behaviours compared to the control group. This type of information on group differences in time reallocations would not have been possible to obtain by comparing group differences in work time-use following the intervention, supporting the usefulness of time flow analysis as a tool to evaluate complex, context-specific interventions.

Heart rate during work and heart rate variability during the following night: a day-by-day investigation on the physical activity paradox among blue-collar workers.

OBJECTIVES: Contrary to leisure-time physical activity, occupational physical activity (OPA) may have harmful health effects, called the physical activity paradox. A proposed mechanism is that OPA can elevate the heart rate (HR) for several hours per day. We aimed to investigate the association between the mean intensity of OPA and HR variability (HRV) indices the following night. METHODS: Three cohorts (NOMAD, DPhacto, and Physical Workload and Fitness) involving blue-collar workers from different sectors were merged in this study. HR monitors (Actiheart) recorded 24-hour inter-beat intervals (IBI) for up to four consecutive days. The relative intensity of the mean HR during work was estimated by HR reserve (%HRR), and time-domain indices of HRV were analyzed during the following night. Data were analyzed using a multilevel growth model to test the association between mean %HRR during work and HRV indices at night in a day-by-day analysis adjusted for age, BMI, alcohol consumption, smoking, and occupation. RESULTS: The dataset included a sample of 959 Danish blue-collar workers, with a mean %HRR during work of 31%, and 42% worked at an intensity ≥30%HRR. The multilevel model showed negative within- and between-subject associations between %HRR during work and HRV indices at night. CONCLUSIONS: Our results indicate a higher %HRR during work to associate with lower HRV indices the following night and a higher HR, reflecting an imbalanced autonomic cardiac modulation. This finding supports a high mean HR during work to be a potential underlying mechanism for the harmful health effect of OPA.

Trends in Walking, Moderate, and Vigorous Physical Activity Participation Across the Socioeconomic Gradient in New South Wales, Australia From 2002 to 2015.

BACKGROUND: A combination of walking, other moderate physical activity, and vigorous physical activity is recommended for achieving good health. Vigorous activity has unique health benefits but may be less accessible to disadvantaged people. To reduce health inequity, we need to understand the differences in physical activity participation among socioeconomic subgroups and whether this is changing over time. METHODS: Data from the 2002 to 2015 Adult New South Wales Population Health Surveys (164,652 responses) were analyzed to investigate trends in walking, moderate and vigorous physical activity participation by socioeconomic status as measured by educational attainment. Analysis used age- and sex-adjusted multivariable linear models that accounted for complex survey design. RESULTS: In 2002, the highest socioeconomic group spent 18.5 (95% confidence interval, 8.2-28.8) minutes per week more than the lowest socioeconomic group being vigorously active. By 2015, this gap had steadily increased to 41.4 (95% confidence interval, 27.6-55.1) minutes per week. Inequity between groups was also found for duration of moderate activity but not for time spent walking. CONCLUSIONS: Low participation in vigorous activity in the lowest socioeconomic group is likely driving increasing inequities in physical activity and widening participation gaps over time. Barriers preventing the most disadvantaged people in New South Wales from engaging in vigorous activity should be addressed urgently.

The physical activity paradox revisited: a prospective study on compositional accelerometer data and long-term sickness absence.

BACKGROUND: The 'physical activity paradox' advocates that leisure physical activity (PA) promotes health while high occupational PA impairs health. However, this paradox can be explained by methodological limitations of the previous studies-self-reported PA measures, insufficient adjustment for socioeconomic confounding or not addressing the compositional nature of PA. Therefore, this study investigated if we still observe the PA paradox in relation to long-term sick absence (LTSA) after adjusting for the abovementioned limitations. METHODS: Time spent on moderate-to-vigorous physical activity (MVPA) and remaining physical behaviors (sedentary behavior, standing, light PA and time in bed) at work and in leisure was measured for 929 workers using thigh accelerometry and expressed as isometric log-ratios (ilrs). LTSA was register-based first event of ≥6 consecutive weeks of sickness absence during 4-year follow-up. The association between ilrs and LTSA was analyzed using a Cox proportional hazards model adjusted for remaining physical behaviors and potential confounders, then separately adjusting for and stratifying by education and type of work. RESULTS: During the follow-up, 21% of the workers experienced LTSA. In leisure, more relative MVPA time was negatively associated with LTSA (20% lower risk with 20 min more MVPA, p = 0.02). At work, more relative MVPA time was positively associated with LTSA (15% higher risk with 20 min more MVPA, p = 0.02). Results remained unchanged when further adjusted for or stratified by education and type of work. CONCLUSION: These findings provide further support to the 'PA paradox'.

Light-intensity physical activity derived from count or activity types is differently associated with adiposity markers.

AIM: The aim of this study was to compare the association between count- and activity type-based definitions of light-intensity physical activity (LIPA) and adiposity markers. METHODS: A total of 516 Danish workers participated in 1-4 days of hip- and thigh-based accelerometer measurements. Three definitions of average daily time spent in LIPA were derived: LIPA (1) time spent between 100 and 2029 CPM, LIPA (2) time spent moving and slow walking, and LIPA (3) time spent moving, walking slow, and standing. Adiposity markers were body mass index (BMI), body fat percentage, and waist circumference. The cross-sectional association between the three LIPA definitions and adiposity markers was analyzed and interpreted using compositional regression models followed by reallocation of time between LIPA, moderate-to-vigorous physical activity (MVPA), and sedentary behavior (SB), respectively. RESULTS: The geometric means of daily time (min/day) spent in LIPA 1, LIPA 2, and LIPA 3 were 326, 102, and 274, respectively. We found the direction and strength of the association between the relative importance of daily time spent in LIPA and the adiposity markers to depend on the LIPA definition. For example, reallocating 30 minutes from MVPA to LIPA 1, LIPA 2 and LIPA 3 were associated with a 2.97 (95% CI: 0.68; 5.27), -0.71 (95% CI: -1.43; 0.02), and -0.45 (95% CI: -1.01; 0.11) difference in BMI, respectively. CONCLUSION: Our findings highlight the need for caution when comparing results from studies using different definitions of LIPA.

Is high aerobic workload at work associated with leisure time physical activity and sedentary behaviour among blue-collar workers? A compositional data analysis based on accelerometer data.

OBJECTIVE: This study aimed to investigate the hypothesized negative association between duration of work time spent at a high relative aerobic workload and leisure time movement behaviours among blue-collar workers. METHODS: This was a cross-sectional study based on heart rate and accelerometer data from 803 blue-collar workers (447 men and 356 women). Relative aerobic workload was measured as percentage of heart rate reserve during work (%HRR). Leisure time movement behaviours were expressed in terms of leisure time spent in sedentary and active behaviours in uninterrupted bouts (i.e. <10 min, ≥10-30 min and >30 min). Compositional regression and isotemporal substitution models were used to assess the association between the predominance of work time spent at ≥40%HRR and leisure time spent in sedentary and active bouts. All analyses were stratified by sex. RESULTS: For men, there was no statistically significant association between the predominance of work time spent at ≥40%HRR and leisure time movement behaviours. Among women, the predominance of ≥40%HRR at work was negatively associated with relative leisure time spent in ≥10 min bouts of active behaviour ([Formula: see text] = -0.21, p = 0.02) and a theoretical 15 min reallocation of work time from <40%HRR to ≥40%HRR was estimated to decrease active behaviour by 6 min during leisure time. CONCLUSION: Our result highlights the need for considering work-related barriers for an active leisure time in high-risk populations. Longitudinal studies are warranted to disentangle the relationship between physically demanding work characteristics and leisure time movement behaviours in such populations.

Acute effect on ambulatory blood pressure from aerobic exercise: a randomised cross-over study among female cleaners.

PURPOSE: High occupational physical activity (OPA) is shown to increase the risk for elevated blood pressure, cardiovascular diseases and mortality. Conversely, aerobic exercise acutely lowers the blood pressure up to 25 h post exercise. However, it is unknown if this beneficial effect also apply for workers exposed to high levels of OPA. Cleaners constitute a relevant occupational group for this investigation because of a high prevalence of OPA and cardiovascular disease. Accordingly, the objective was to investigate the acute effects on ambulatory blood pressure from a single aerobic exercise session among female cleaners. METHODS: Twenty-two female cleaners were randomised to a cross-over study with a reference and an aerobic exercise session. Differences in 24-h, work hours, leisure time, and sleep ambulatory blood pressure (ABP) were evaluated using repeated measure 2 × 2 mixed-models. RESULTS: After the aerobic exercise session, the 24-h systolic ambulatory blood pressure was significantly lowered by 2.4 mmHg (p < 0.01) compared to the reference session. The 24-h diastolic ABP was unaltered. During work hours, a lowered systolic ABP of 2.2 mmHg (p = 0.02) and a higher diastolic ABP of 1.5 mmHg (p = 0.03) were found after the aerobic exercise session. During leisure time, the systolic ABP was lowered by 1.7 mmHg (p = 0.04) and the diastolic ABP was unaltered. During sleep, the systolic and diastolic ABP was unaltered. CONCLUSION: A single aerobic exercise session lowered 24-h systolic ABP of 2.4 mmHg. Thus, an aerobic exercise session seems to be beneficial for lowering the risk of hypertension among cleaners.

Change in health-related quality of life over 1 month in cancer patients with high initial levels of symptoms and problems.

PURPOSE: To investigate the mean changes over time in health-related quality of life among advanced cancer patients who did not receive any intervention, comparing changes among all patients versus changes in subgroups of patients with high initial symptom scores. METHODS: Patients with advanced cancer answered two questionnaires, containing the EORTC QLQ-C30 (15 multi- or single-item scales), with approximately 1 month in between and received no known intervention in between. For each QLQ-C30 scale, we estimated the mean change among all patients and in subgroups of patients scoring at least 33, 50, and 66 %, respectively, of maximum (maximal symptom score or maximally reduced function score) in the first questionnaire. RESULTS: In total, 1014 patients completed both questionnaires. As hypothesized, we found no change over time in mean scores when including all patients [average mean change = -0.9 (95 % CI -1.5;-0.6)]. In the subgroups of patients initially scoring at least 33, 50, or 66 % of maximum, the score improved with mean changes of -9.2 (95 % CI -10.1;-8.4), -13.1 (95 % CI -14.4;-11.8), and -15.6 (95 % CI -17.2;-13.9), respectively. CONCLUSIONS: We quantified the magnitude of change over a 1-month period in health-related quality of life in advanced cancer patients, and in subgroups selected according to certain initial symptom levels. This information may help the interpretation of longitudinal studies of patients selected via screening.

Effects of melatonin on physical fatigue and other symptoms in patients with advanced cancer receiving palliative care: A double-blind placebo-controlled crossover trial.

BACKGROUND: Patients with advanced cancer often experience fatigue and other symptoms that negatively impact their quality of life. The current trial investigated the effect of melatonin on fatigue and other symptoms in patients with advanced cancer. METHODS: Patients who were aged ≥18 years, had a histologically confirmed stage IV cancer (TNM Classification), and who reported feeling significantly tired were recruited from the palliative care unit at the study institution. The study was a double-blind, randomized, placebo-controlled crossover trial. Patients received 1 week of melatonin at a dose of 20 mg or a placebo orally each night, before crossing over and receiving the opposite treatment for 1 week. Between the 2 periods, a washout period of 2 days was implemented. Outcomes were measured using the Multidimensional Fatigue Inventory (MFI-20) and The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire. Physical fatigue from the MFI-20 was the primary outcome. The primary analysis was a complete complier analysis (ie, it included only those patients who had consumed at least 5 capsules per week and who had answered the MFI-20 on days 1, 7, 10, and 17). Sensitivity analysis using multiple imputations including all randomized patients and all patients completing the intervention were conducted. RESULTS: A total of 72 patients were randomized. Fifty patients completed the intervention and 44 patients were complete compliers. No significant differences between the placebo and melatonin periods were found for physical fatigue, secondary outcomes, or explorative outcomes. CONCLUSIONS: In the current study, oral melatonin at a dose of 20 mg was not found to improve fatigue or other symptoms in patients with advanced cancer.