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The purpose of this study was to describe the accelerometry-based characteristics of overall sedentary behavior (SB) and sitting among adults under free-living conditions. Thirty-six (mean age 47.6 years) volunteers carried a waist-worn accelerometer for ≥4 days with data ≥600 min/d during 14 consecutive days. A machine learning (ML) based method was used to classify the patterns of SB and sitting from raw 3D acceleration. The participants spent most (69.3%) of their waking time in SB, and a half (52.2%) of the SB was performed in a sitting posture. Men broke their overall sedentary time less often (4.1 vs. 6.1 bouts/h), but women sat more; however, women broke their sitting time as often as men (7.6 bouts/h). This study confirms that SB and sitting can be distinguished using ML methods, and more information about SB can be achieved when overall SB and sitting are analyzed separately in free-living conditions. [ABSTRACT FROM AUTHOR]

Cardiorespiratory fitness (CRF) and physical activity (PA) are associated with autonomic function, but their associations to orthostatic autonomic responses are unclear in epidemiological setting. We hypothesized that higher CRF and PA would associate with higher immediate vagal responses and lower incidence of adverse findings during orthostatic test. At age of 46, 787 men and 938 women without cardiorespiratory diseases and diabetes underwent an orthostatic test (3‐minutes sitting, 3‐minutes standing) with recording of RR intervals (RRi) and blood pressure (BP) by finger plethysmography. Acute responses of RRi (30:15 ratio) and BP were calculated. CRF was measured by a submaximal step test and daily amount of moderate‐to‐vigorous PA (MVPA) for 2 weeks by wrist‐worn accelerometer. Lifelong PA was based on questionnaires at ages of 14, 31, and 46. High CRF was significantly associated with higher RRi 30:15 ratio (adjusted standardized β = 0.17, P < 0.001) and milder acute decrease of systolic BP while standing (β = 0.10, P = 0.001), while MVPA was not (β = 0.04 for RRi 30:15 ratio and β = 0.05 for systolic BP acute response). High lifelong PA was significantly associated with higher RRi 30:15 ratio (β = 0.08, P = 0.002) but not with acute systolic BP response. Those in the lowest tertile of CRF had 9.2‐fold risk (P = 0.002) of having postural orthostatic tachycardia syndrome compared to more fit. Cardiorespiratory fitness and lifelong physical activity, but not current physical activity, were independently associated with higher cardiac vagal response to orthostasis. The present results underscore the importance fitness and lifelong physical activity in prevention of abnormal autonomic function and related cardiovascular risk. [ABSTRACT FROM AUTHOR]

Background: Modic changes (MC) in the lumbar spine are considered one potential etiological factor behind low back pain (LBP). Multiple risk factors for MC have been suggested, including male gender, smoking and factors affecting hyperloading and mechanical stress such as high body mass index (BMI), strenuous physical work and high occupational and leisure-time physical activity (PA). So far, the effect of PA on the occurrence of MC has remained under debate due to contradictory findings. The purpose of this study was to investigate the possible association between device-measured moderate-to-vigorous PA (MVPA) (≥ 3.5 METs) and lumbar MC.Methods: The study had 1374 participants from the Northern Finland Birth Cohort 1966. At the age of 46-48, PA was measured by a wrist-worn accelerometer, and lumbar magnetic resonance imaging (MRI) was carried out to determine MC. We analyzed the association between Type 1 (MC1) and Type 2 (MC2) MC and daily amount of MVPA (min/day) using sex-stratified logistic regression models before and after adjustment for BMI, socioeconomic status, smoking, and accelerometer wear time.Results: Among men, increased amount of MVPA was positively associated with any MC (adjusted OR corresponding to every 60 min/day of MVPA 1.41; 95% confidence interval (CI) 1.01 to 1.95) and MC2 (OR 1.54; 95% CI 1.14 to 2.08), but not with MC1 (OR 1.06; 95% CI 0.80 to 1.39). Among women, we only found a positive association between MVPA and MC1 before adjustments (unadjusted OR 1.42; 95% CI 1.06 to 1.92).Conclusion: Among men, increased amount of MVPA was associated with increased odds of any MC and particularly MC2. Among women, MVPA was not independently associated with MC. [ABSTRACT FROM AUTHOR]

Background: Given the high global prevalence of physical inactivity, there is a need to design cities that support active modes of transportation. High density diverse neighborhoods with good access networks have been associated with enhanced walking and cycling, but there is a lack of large-scale longitudinal studies utilizing a life course perspective to model residential relocation trajectories. The objectives of the present longitudinal study were to model and visualize residential relocation trajectories between 31 and 46 years of age based on neighborhood density, mixed land use and access networks (DMA), and to assess neighborhood DMA as a predictor of self-reported regular walking and cycling and objectively measured physical activity. Methods: Based on data from the Northern Finland Birth Cohort 1966 (N = 5947), we used self-reported regular walking and cycling and objectively measured physical activity as outcome variables and objectively assessed neighborhood DMA as the main explanatory variable. We conducted sequence analysis to model residential relocation trajectories, and generalized linear mixed models and Fisher's exact test were used to explore longitudinal associations between neighborhood DMA and physical activity. Results: Over 80% of the participants lived in a neighborhood with the same level of neighborhood DMA during the follow-up. Relocation occurred more often from higher to lower DMA neighborhoods than reverse. Increased neighborhood DMA was associated with increased regular walking (OR 1.03; 95% CI: 1.00, 1.05; p = 0.023) and cycling (OR 1.17; 95% CI: 1.12, 1.23; p < 0.001). Residential relocation trajectory from lower to highest neighborhood DMA increased the odds of starting regular walking (OR 3.15; 95% CI: 1.50, 7.14; p = 0.001) and cycling (OR 2.63; 95% CI: 1.23, 5.79; p = 0.009) as compared to higher to lower neighborhood DMA trajectory. Conclusions: The results strongly support the hypothesis that increasing urban DMA can enhance regular walking and cycling at population level and so improve public health. The findings have implications for zoning and transportation policies, favoring the creation of dense and diverse neighborhoods with good access networks to support regular walking and cycling. [ABSTRACT FROM AUTHOR]