Reducing sitting time versus adding exercise: differential effects on biomarkers of endothelial dysfunction and metabolic risk

Isotemporal substitution of physical activity patterns and sitting time with obesity indicators among workers in São Paulo

This study aimed to evaluate the association between substituting 10, 30, and 60 min/day of physical activity and sitting time with obesity indicators among workers. It is a cross-sectional study involving 394 adults (76.6% women) from São Paulo, Brazil. Physical activity and sitting time (min/day) were measured using the short version of the International Physical Activity Questionnaire (IPAQ) to determine physical activity levels. Obesity indicators included body mass index (BMI; kg/m²), waist circumference (cm), and body fat (kg). Isotemporal substitution models were analyzed using multivariate linear regression, adjusted for sociodemographic variables. Participants reported median values of 150.0 min/day (IQR: 60.0-360.0) for walking and 445.7 min/day (IQR: 317.1-565.7) for sitting time. The median values for BMI, waist circumference, and body fat were 27.1 kg/m², 91.0 cm, and 23.5 kg, respectively. Substituting 10 min/day of sitting time for 10 min/day of walking was associated with waist circumference (β: -0.216: 95% CI: -0.041; -0.007). In addition, substituting 60 min/day of sitting time for moderate physical activity (β -0.206; 95% CI: -0.123; -0.008) was negatively associated with body fat. The equivalent substitution of different periods of sitting time for more active behaviors was favorably associated with obesity indicators. These findings suggest that lifestyle interventions based on replacing sitting time with physical activity can reduce the obesity epidemic in adults.

Endothelial Dysfunction in Acute Myocardial Infarction: A Complex Association With Sleep Health, Traditional Cardiovascular Risk Factors and Prognostic Markers

BACKGROUND

Endothelial function (EndFx) is a core component of cardiovascular (CV) health and cardioprotection following acute myocardial infarction (AMI) treated with primary percutaneous coronary intervention (PCI).

HYPOTHESIS

AMI patients experience endothelial dysfunction (EndDys), associated with traditional CV risk factors and sleep patterns. EndFx may also predict short and mid-term outcomes.

METHODS

EndFx was assessed in 63 patients (56.2 ± 7.6 years) using the Endothelium Quality Index (EQI). Sleep quality and quantity were evaluated using objective (actigraphy) and subjective (Pittsburgh Sleep Quality Index questionnaire) measures. Cardiorespiratory fitness was quantified through the 6-min walking test. Cardiac function was assessed using the left ventricular ejection fraction.

RESULTS

Following AMI, patients tended to experience EndDys (EQI = 1.4 ± 0.7). A severe EndDys was observed in 23.8% of patients (n = 15), while a mild EndDys was present in 63.49% (n = 40). Furthermore, EndDys was significantly associated with traditional CV risk factors (i.e., low physical activity level [12.8%], age [-4.2%], and smoking [-0.7%]) (R2 adjusted = 0.50, p < 0.001). Patients with EndDys had poor sleep quality (p = 0.001) and sleep efficiency (p = 0.016) compared to healthy persons. Patients with severe EndDys exhibited lower cardiorespiratory fitness compared to those with healthy EndFx (p = 0.017). Furthermore, during a follow-up period (nearly 4 months) following PCI, major adverse cardiac events were observed in four patients with severe EndDys.

CONCLUSIONS

Our results emphasize the importance of adequate sleep and an active lifestyle, notably physical activity practice, as modifiable elements to enhance EndFx, which is regarded as a predictive tool following AMI. However, other factors remain to be elucidated as predictors of CV risk.

TRIAL REGISTRATION

The study protocol was registered in the Pan African Clinical Trial Registry under the trial ID: PACTR202208834230748.

Effect of physical activity breaks during prolonged sitting on vascular outcomes: A scoping review

Emerging evidence claims the vascular benefits of varied frequency and duration of physical activity (PA) breaks, whereas the efficacy of varied intensity remains unexplored. We aimed to collate and summate the studies investigating the PA breaks at various intensities on vascular protection. Seven electronic databases were searched for potential studies till Jan 31, 2022. The eligible studies should have administered PA breaks of differing intensities in prolonged sitting postures and explored regional vascular changes [flow mediated dilation (FMD), shear stress, diameter, and blood flow] using ultrasound and novel outcome markers. Two independent reviewers assessed the studies for eligibility after abstract and full-text screen, and appropriate data were extracted to summarise vascular protective effects with PA breaks. Our findings reveal adverse regional vascular outcomes with prolonged sitting (FMD ≈ -1.5%, diameter ≈ -0.06 mm), whereas PA breaks of any intensity were found to improve endothelial functions (FMD ≈ +0.5%, diameter ≈ +0.1 mm, shear ≈ +13 s-1) and mitigate the adverse effects associated with prolonged sitting. Compared with high-intensity activity, low-intensity PA breaks alleviate arterial stiffness and endothelial dysfunction risks.

Effectiveness of wearable technology to optimize youth soccer players' off-training behaviour and training responses: a parallel group randomized trial

BACKGROUND

Although youth soccer players meet and exceed the weekly physical activity (PA) guidelines also exhibit high off-training sedentary behaviour (SB) levels. Recent evidence indicated that low PA preceding training leads to decreased PA intensity in soccer practice and that SB impairs sports performance and recovery. Thus, a parallel group randomized trial examined the effect of activity wristbands on young players' off-training PA and SB profiles; assessed the added value of wearable wristbands with PA warnings; and investigated whether manipulating off-training PA can affect the players' training responses.

METHODS

Thirty-two adolescent soccer players (16.1 ± 0.9 years old) were monitored during weekdays for two weeks (interspersed with one week). Players were randomly assigned to a reminder to move (REM) and a non-reminder to move group (nREM). The REM wore an activity wristband (Fitbit Charge 2) with PA warnings in the last week of research, while the nREM wore identical monitors without PA feedback. Throughout the study, off-training PA was assessed using tri-axial accelerometers, and training responses were analysed using wearable inertial monitoring units. Gardner-Altman estimation plots and a Fisher's Exact Test of Independence estimated each group's off-training PA changes between the monitored weeks. Complementary, an analysis of covariance (ANCOVA) quantified the effect of Fitbit wristband configurations (with a reminder to move or without a reminder to move) on the off-training PA and soccer training external load variables. The independent variable group had two levels (REM and nREM). The off-training PA and training load values collected in the first week were introduced in the model as a covariate, the groups were designated fixed factors and the off-training PA and training load from the third week were the dependent variables. The team was also included as a covariate and the between-group differences post-intervention were adjusted for baseline and team.

RESULTS

Interestingly, results showed that different wearable wristbands did not influence the players' off-training PA profiles (p > 0.05). Concomitantly, no differences were observed in training responses (p > 0.05).

CONCLUSION

Findings emphasize the importance of health and youth sports organizations in developing newer approaches for promoting healthier lifestyles, beyond training practices, with potentially favourable implications for sports performance.

Physiology of sedentary behavior

Sedentary behaviors (SB) are characterized by low energy expenditure while in a sitting or reclining posture. Evidence relevant to understanding the physiology of SB can be derived from studies employing several experimental models: bed rest, immobilization, reduced step count, and reducing/interrupting prolonged SB. We examine the relevant physiological evidence relating to body weight and energy balance, intermediary metabolism, cardiovascular and respiratory systems, the musculoskeletal system, the central nervous system, and immunity and inflammatory responses. Excessive and prolonged SB can lead to insulin resistance, vascular dysfunction, shift in substrate use toward carbohydrate oxidation, shift in muscle fiber from oxidative to glycolytic type, reduced cardiorespiratory fitness, loss of muscle mass and strength and bone mass, and increased total body fat mass and visceral fat depot, blood lipid concentrations, and inflammation. Despite marked differences across individual studies, longer term interventions aimed at reducing/interrupting SB have resulted in small, albeit marginally clinically meaningful, benefits on body weight, waist circumference, percent body fat, fasting glucose, insulin, HbA1c and HDL concentrations, systolic blood pressure, and vascular function in adults and older adults. There is more limited evidence for other health-related outcomes and physiological systems and for children and adolescents. Future research should focus on the investigation of molecular and cellular mechanisms underpinning adaptations to increasing and reducing/interrupting SB and the necessary changes in SB and physical activity to impact physiological systems and overall health in diverse population groups.

Effects of increasing light versus moderate-to-vigorous physical activity on cardiometabolic health in Chinese adults with obesity

Increasing daily physical activity (PA) is a practical way to decrease the risk of cardiometabolic diseases, while the studies on exercise intensity remain limited. The purpose of the present study was to compare the effects of increasing light PA (LPA) or moderate-to-vigorous PA (MVPA) for 12 weeks on cardiometabolic markers in Chinese adults with obesity. Fifty-three adults were randomly assigned to the 1) control group, 2) LPA group, and 3) MVPA group in free-living settings. The intervention effects on body composition, cardiorespiratory fitness, and cardiometabolic biomarkers were analysed using a generalized estimated equation model adjusted for baseline values and potential confounders. Compared with the control group, the MVPA group showed improvements in body composition, lipids, C-peptide, monocyte chemoattractant protein-1 (MCP-1), interleukin-8, leptin, and E-selectin. A favourable change in triglycerides and E-selectin were observed in the LPA group when compared to the control group. Lastly, improvements in waist circumference, C-reactive protein, and MCP-1 were observed in the MVPA group when compared to those in the LPA group. Although increasing both LPA and MVPA improved certain cardiometabolic biomarkers, the latter may have more benefits. These findings imply that MVPA may reduce cardiometabolic disease risk more effectively than LPA, especially in Chinese adults with obesity.

Substituting device-measured sedentary time with alternative 24-hour movement behaviours: compositional associations with adiposity and cardiometabolic risk in the ORISCAV-LUX 2 study

BACKGROUND

There is a considerable burden of sedentary time in European adults. We aimed to quantify the differences in adiposity and cardiometabolic health associated with theoretically exchanging sedentary time for alternative 24 h movement behaviours.

METHODS

This observational cross-sectional study included Luxembourg residents aged 18-79 years who each provided  ≥ 4 valid days of triaxial accelerometry (n = 1046). Covariable adjusted compositional isotemporal substitution models were used to examine if statistically replacing device-measured sedentary time with more time in the sleep period, light physical activity (PA), or moderate-to-vigorous PA (MVPA) was associated with adiposity and cardiometabolic health markers. We further investigated the cardiometabolic properties of replacing sedentary time which was accumulated in prolonged (≥ 30 min) with non-prolonged (< 30 min) bouts.

RESULTS

Replacing sedentary time with MVPA was favourably associated with adiposity, high-density lipoprotein cholesterol, fasting glucose, insulin, and clustered cardiometabolic risk. Substituting sedentary time with light PA was associated with lower total body fat, fasting insulin, and was the only time-exchange to predict lower triglycerides and a lower apolipoprotein B/A1 ratio. Exchanging sedentary time with more time in the sleep period was associated with lower fasting insulin, and with lower adiposity in short sleepers. There was no significant evidence that replacing prolonged with non-prolonged sedentary time was related to outcomes.

CONCLUSIONS

Artificial time-use substitutions indicate that replacing sedentary time with MVPA is beneficially associated with the widest range of cardiometabolic risk factors. Light PA confers some additional and unique metabolic benefit. Extending sleep, by substituting sedentary time with more time in the sleep period, may lower obesity risk in short sleepers.

Effects of physical activity breaks during prolonged sitting on vascular and executive function—A randomised cross-over trial

Objectives

High sedentary behaviour is associated with adverse effects on central vascular function and cognitive function. Although interventions to mitigate the adverse effects of workplace sitting are intriguing, evidence of the efficacy of such interventions remains lacking. This randomised cross-over trial was aimed at exploring the effectiveness of prolonged sitting, with or without physical activity breaks, on central, peripheral vascular and cognitive function in adults.

Methods

Twenty one healthy adults completed 4 h of simulated work conditions in three experimental visits: (1) uninterrupted sitting (SIT); (2) sitting interrupted by 3 min of walking every hour (LIT); and (3) sitting interrupted by 3 min of stair climbing every hour (MIT). Carotid (CA) and superficial femoral artery (SFA) diameter, velocity, shear rate and blood flow were measured with Duplex ultrasound at 50 MHz at three time points (hours 0, 2 and 4), and executive function was assessed with the computer based Eriksen Flanker task every hour.

Results

The decreases in reaction time (-30.59%) and accuracy (-10.56%) during SIT conditions were statistically significant, and less of a decrease was observed under LIT and MIT conditions. No significant differences in CA and SFA function were observed with LIT and MIT interventions.

Conclusion

Physical activity breaks of varying intensity during prolonged sitting improve reaction time. However, the vascular benefits of physical activity breaks should be confirmed in the future through long term studies in natural environment.

Angiotensin-converting enzyme gene (ACE) polymorphisms are associated with dysregulation of biochemical parameters in hypertensive patients

INTRODUCTION

The genetic component, including genes and their variants, plays a significant role in the pathophysiology of arterial hypertension (AH). Thus, clinical, epidemiological and genetic studies have been carried out to improve the understanding of disease mechanisms, improve diagnostic quality and contribute to prevention.

OBJECTIVE

To determine the association of risk factors, biochemical parameters and different ACE gene polymorphisms with AH.

METHOD

The case-control study was carried out in the population of Ouro Preto, Brazil. The subjects answered a questionnaire containing clinical and sociodemographic data. The ACE gene polymorphisms rs4291, rs4363 and rs4335 were evaluated by real time-polymerase chain reaction (real-time PCR) in 310 people (155 hypertensive and 155 normotensive patients), in addition to biochemical parameters. A multivariate logistic regression model was used to identify factors associated with AH. Analysis of continuous variables was performed using the Kruskal-Wallis test to assess significance between groups and Dunn's post-test for multiple comparisons.

RESULTS

The results showed that AH was associated with age, education, smoking, obesity and high levels of triglycerides, sodium, glucose and uric acid. Regarding the biochemical parameters, in hypertensive patients, the rs4363 and rs4335 polymorphisms were associated with high levels of triglycerides, urea and glucose; the rs4291 polymorphism was associated with elevated urea and glucose levels. No association was detected between SNPs and HA.

CONCLUSION

AH was associated with socioeconomic status, lifestyle habits and biochemical parameters. ACE polymorphisms may have influenced the levels of triglycerides, urea and glucose in hypertensive patients.

Accelerometer measured physical activity and sedentary time in individuals with multiple sclerosis versus age matched controls: A systematic review and meta-analysis

BACKGROUND

People with Multiple Sclerosis (PwMS) find it more difficult to engage in physical activity (PA) than healthy controls. Accelerometers can be used to measure sedentary time and free-living physical activity, understanding the differences between PwMS and controls can help inform changes such as interventions to promote a more active lifestyle. This in turn will help prevent secondary conditions and reduce symptom progression.

OBJECTIVE

To conduct a systematic review and meta-analysis on accelerometer measured sedentary behavior and physical activity between PwMS and healthy controls.

METHODS

A systematic search of five databases (PubMed, Web of Science, Ovid, Science Direct and CINAHIL) from inception until 22nd November 2019. Inclusion criteria was (1) included a group of participants with a definite diagnosis of multiple sclerosis of any type; (2) have 3 or more days of PA monitoring using accelerometers during free living conditions; (3) include age matched healthy controls; (4) assess adults over the age of 18; (5) reported data had to have been reported in a manner suitable for quantitative pooling including: percent of time spent sedentary, minutes per day of sedentary, light, moderate, vigorous activity (moderate and vigorous totaled together), steps per day or counts per day.

RESULTS

Initial search produced 9021 papers, after applying inclusion criteria 21 eligible papers were included in the study. One paper was a longitudinal study from which only baseline data was included. One paper was a reliability and validity study, with data for PwMS versus controls in the validity section. All other papers are cross sectional, with one being a pilot study and another a random control study. One paper used two devices in unison, only one set of data is included in the statistics. Outcome data was available for 1098 participants, 579 PwMS and 519 healthy controls. Significant differences were seen in all categories tested: (1) sedentary time (min/day), standard mean difference -0.286, P = 0.044, n = 4 studies; (2) relative sedentary time (%/day), standard mean difference -0.646, P = 0.000, n = 5 studies; (3) LPA (min/day), standard mean difference 0.337, P = 0.039, n = 5 studies; (4) relative LPA (%/day), standard mean difference 0.211, P = 0.152, n = studies; (5) MVPA (min/day), standard mean difference 0.801, P = 0.000, n = 8 studies; (6) relative MVPA (%/day), mean difference 0.914, P = 0.000, n = 5 studies; (7) step count, standard mean difference 0.894, P = 0.000, n = 8 studies; (8) activity count, standard mean difference 0.693, P = 0.000, n = 13 studies.

CONCLUSION

PwMS are more sedentary and engage in less LPA, MVPA, steps per day and accelerometer counts per day than healthy controls when measured using accelerometers during free-living conditions.

Detrimental effects of physical inactivity on peripheral and brain vasculature in humans: Insights into mechanisms, long-term health consequences and protective strategies

The growing prevalence of physical inactivity in the population highlights the urgent need for a more comprehensive understanding of how sedentary behaviour affects health, the mechanisms involved and what strategies are effective in counteracting its negative effects. Physical inactivity is an independent risk factor for different pathologies including atherosclerosis, hypertension and cardiovascular disease. It is known to progressively lead to reduced life expectancy and quality of life, and it is the fourth leading risk factor for mortality worldwide. Recent evidence indicates that uninterrupted prolonged sitting and short-term inactivity periods impair endothelial function (measured by flow-mediated dilation) and induce arterial structural alterations, predominantly in the lower body vasculature. Similar effects may occur in the cerebral vasculature, with recent evidence showing impairments in cerebral blood flow following prolonged sitting. The precise molecular and physiological mechanisms underlying inactivity-induced vascular dysfunction in humans are yet to be fully established, although evidence to date indicates that it may involve modulation of shear stress, inflammatory and vascular biomarkers. Despite the steady increase in sedentarism in our societies, only a few intervention strategies have been investigated for their efficacy in counteracting the associated vascular impairments. The current review provides a comprehensive overview of the evidence linking acute and short-term physical inactivity to detrimental effects on peripheral, central and cerebral vascular health in humans. We further examine the underlying molecular and physiological mechanisms and attempt to link these to long-term consequences for cardiovascular health. Finally, we summarize and discuss the efficacy of lifestyle interventions in offsetting the negative consequences of physical inactivity.

Sitting less and moving more for improved metabolic and brain health in type 2 diabetes: 'OPTIMISE your health' trial protocol

BACKGROUND

Clinical practice guidelines recommend that adults with type 2 diabetes (T2D) sit less and move more throughout the day. The 18-month OPTIMISE Your Health Clinical Trial was developed to support desk-based workers with T2D achieve these recommendations. The two-arm protocol consists of an intervention and control arms. The intervention arm receives 6 months health coaching, a sit-stand desktop workstation and an activity tracker, followed by 6 months of text message support, then 6 months maintenance. The control arm receives a delayed modified intervention after 12 months of usual care. This paper describes the methods of a randomised controlled trial (RCT) evaluating the effectiveness and cost-effectiveness of the intervention, compared to a delayed intervention control.

METHODS

This is a two-arm RCT being conducted in Melbourne, Australia. Desk-based workers (≥0.8 full-time equivalent) aged 35-65 years, ambulatory, and with T2D and managed glycaemic control (6.5-10.0% HbA1c), are randomised to the multicomponent intervention (target n = 125) or delayed-intervention control (target n = 125) conditions. All intervention participants receive 6 months of tailored health coaching assisting them to "sit less" and "move more" at work and throughout the day, supported by a sit-stand desktop workstation and an activity tracker (Fitbit). Participants receive text message-based extended care for a further 6-months (6-12 months) followed by 6-months of non-contact (12-18 months: maintenance). Delayed intervention occurs at 12-18 months for the control arm. Assessments are undertaken at baseline, 3, 6, 12, 15 and 18-months. Primary outcomes are activPAL-measured sitting time (h/16 h day), glycosylated haemoglobin (HbA1c; %, mmol/mol) and, cognitive function measures (visual learning and new memory; Paired Associates Learning Total Errors [adjusted]). Secondary, exploratory, and process outcomes will also be collected throughout the trial.

DISCUSSION

The OPTIMISE Your Health trial will provide unique insights into the benefits of an intervention aimed at sitting less and moving more in desk-bound office workers with T2D, with outcomes relevant to glycaemic control, and to cardiometabolic and brain health. Findings will contribute new insights to add to the evidence base on initiating and maintaining behaviour change with clinical populations and inform practice in diabetes management.

TRIAL REGISTRATION

ANZCTRN12618001159246 .

Sedentary behaviour and physical activity are associated with biomarkers of endothelial dysfunction and low-grade inflammation-relevance for (pre)diabetes: The Maastricht Study

AIMS/HYPOTHESIS

Biomarkers of endothelial dysfunction and low-grade inflammation are important in the pathogenesis of CVD and can potentially be modified by physical activity and sedentary behaviour. Effects of physical activity on biomarkers of endothelial dysfunction may be especially prominent in type 2 diabetes.

METHODS

In the population-based Maastricht Study (n = 2363, 51.5% male, 28.3% type 2 diabetes, 15.1% prediabetes [defined as impaired glucose tolerance and impaired fasting glucose]), we determined biomarkers of endothelial dysfunction and low-grade inflammation, and combined z scores were calculated. Physical activity and sedentary behaviour were measured by activPAL. Linear regression analyses were used with adjustment for demographic, lifestyle and cardiovascular risk factors.

RESULTS

The association between total, light, moderate-to-vigorous and vigorous intensity physical activity and sedentary time on the one hand and biomarkers of endothelial dysfunction on the other were generally significant and were consistently stronger in prediabetes and type 2 diabetes as compared with normal glucose metabolism status (p for interaction <0.05). Associations between physical activity and sedentary behaviour on the one hand and low-grade inflammation on the other were also significant and were similar in individuals with and without (pre)diabetes (p for interaction >0.05).

CONCLUSIONS/INTERPRETATION

Physical activity and sedentary behaviour are associated with biomarkers of endothelial dysfunction and low-grade inflammation. For biomarkers of endothelial dysfunction, associations between physical activity and sedentary behaviour were consistently stronger in (pre)diabetes than in normal glucose metabolism. Whether increasing physical activity or decreasing sedentary time can positively influence biomarkers of endothelial dysfunction in individuals with prediabetes and type 2 diabetes requires further study.

The Acute Effects of Standing on Executive Functioning in Vocational Education and Training Students: The Phit2Learn Study

Research suggests that sedentary behavior (SB) is negatively associated with cognitive outcomes. Interrupting prolonged sitting has been shown to improve cognitive functions, including executive functioning (EF), which is important for academic performance. No research has been conducted on the effect of standing on EF in VET students, who make up a large proportion of the adolescent population and who are known to sit more than other students of this age. In this study, we investigated the acute effects of reducing SB by short time standing on EF in vocational education and training (VET) students. In a randomized crossover study, 165 VET students were first taught for 15 min in seated position. After this, they performed while seated the Letter Memory Test for updating, and the Color Shape Test for shifting and inhibition. Students were randomly assigned to a sitting or standing condition. All students were taught again for 15 min and then took the same tests in the condition they were allocated to, respectively, standing or seated. After 1 week, the test procedure was repeated, in which students switched conditions. Mixed model analyses showed no significant effect of sitting or standing on updating, shifting, or inhibition. Also, no significant differences were found for the order of condition on updating, shifting, or inhibition. Our results suggest that 40 min of standing does not significantly influence EF among VET students.

Physiology of physical inactivity, sedentary behaviours and non-exercise activity: insights from the space bedrest model

Physical inactivity, i.e. not reaching the recommended level of physical activity (PA), and sedentary behaviours (SB), i.e. sitting time, have been associated with increased risk for common metabolic diseases. Recent epidemiological data suggest that high volumes of SB are detrimental to metabolic health, even in the presence of regular exercise, i.e. moderate/vigorous PA. This suggests that the health effects of SB are independent from those of exercise. However, experimentally testing this hypothesis is complicated because of the difficulty in disassociating SB from PA. Bedrest studies, a traditional space science model, can offer new insights. In some bedrest studies, an exercise training protocol has been used to counteract the harmful effects of inactivity. While bedrest induces an inactive and sedentary state, exercise with bedrest represents a unique model of sedentary yet physically active people. Here, we review bedrest studies with and without exercise training. Although exercise training prevents the loss of muscle mass and function, even large volumes of exercise are not sufficient to fully counteract the negative metabolic adaptations triggered by inactivity. This observation supports the existence of independent adverse health effects of SB, but also the potential benefits of non-exercise activity, i.e. daily living light PA. We gathered available data to examine the complex relationships between exercise, non-exercise activity, SB and health outcomes. Given the large amount of SB in modern societies, the sole promotion of exercise, i.e. moderate/vigorous PA may be insufficient, and promotion of light PA may be a complimentary approach to improve health.

Effect of a dynamic seat pan design on spine biomechanics, calf circumference and perceived pain during prolonged sitting

This study investigates the effects of a dynamic seat pan design on sitting biomechanics, perceived pain and seat movement compared to a control. Thirty male participants were recruited for two experimental sessions consisting of a 2-h sitting exposure (standardized typing task). Spine angles, back muscle activity, perceived pain and calf circumference were measured pre and post exposure. Sitting in the dynamic condition resulted in lower pain ratings (p = 0.031), decreased calf circumference (p < 0.001), lower average seat pressure (p < 0.001), and greater seat contact area (p = 0.003) compared to the control. Spine angles and low back EMG for all 6 muscles showed no significant differences between chair conditions. These results suggest this dynamic seat pan design is effective at decreasing several negative components associated with sitting for the occupant. Future work should examine the longer-term effects of dynamic office chair features in the field setting with a more generalizable population.

Protocol for a randomized controlled trial of sitting reduction to improve cardiometabolic health in older adults

Older adults with obesity spend the majority of their waking hours sedentary. Given substantial barriers to regular physical activity in this population, approaches to reduce sedentary time could be an effective health promotion strategy. We present the protocol of a randomized controlled trial to reduce sitting time in older adults with a body mass index of 30 kg/m² or above. Participants (N = 284) will be randomized to receive a sitting reduction intervention (termed I-STAND) or a healthy living focused attention control condition. I-STAND includes 10 contacts with a health coach (10 sessions total) and participants receive a wrist-worn prompting device and portable standing desk. The healthy living condition includes 10 sessions with a health coach to set goals around various topics relating to healthy aging. Participants receive their assigned intervention for 6 months. After 6 months, those receiving the I-STAND condition are re-randomized to receive five booster health coaching sessions by 'phone or no further contact; healthy living participants receive no further contact and those in both conditions are followed for an additional 6 months. Measurements initially included wearing an activPAL device and completing several biometric tests (e.g., blood pressure, HbA1c), at baseline, 3 months, 6 months, and 12 months; however, during the COVID-19 pandemic we shifted to remote assessments and were unable to collect all of these measures. The primary outcomes remained activPAL-assessed sitting time and blood pressure. Recruitment is anticipated to be completed in 2022.

Physical Exercise Protects Against Endothelial Dysfunction in Cardiovascular and Metabolic Diseases

Increasing evidence shows that endothelial cells play critical roles in maintaining vascular homeostasis, regulating vascular tone, inhibiting inflammatory response, suppressing lipid leakage, and preventing thrombosis. The damage or injury of endothelial cells induced by physical, chemical, and biological risk factors is a leading contributor to the development of mortal cardiovascular and cerebrovascular diseases. However, the underlying mechanism of endothelial injury remains to be elucidated. Notably, no drugs effectively targeting and mending injured vascular endothelial cells have been approved for clinical practice. There is an urgent need to understand pathways important for repairing injured vasculature that can be targeted with novel therapies. Exercise training-induced protection to endothelial injury has been well documented in clinical trials, and the underlying mechanism has been explored in animal models. This review mainly summarizes the protective effects of exercise on vascular endothelium and the recently identified potential therapeutic targets for endothelial dysfunction.

Three weeks of interrupting sitting lowers fasting glucose and glycemic variability, but not glucose tolerance, in free-living women and men with obesity

We aimed to determine whether interrupting prolonged sitting improves glycemic control and the metabolic profile of free-living adults with obesity. Sixteen sedentary individuals {10 women/6 men; median [interquartile range (IQR)] age 50 (44-53) yr, body mass index (BMI) 32 (32-35.8) kg/m²} were fitted with continuous glucose and activity monitors for 4 wk. After a 1-wk baseline period, participants were randomized into habitual lifestyle (Control) or frequent activity breaks from sitting (FABS) intervention groups. Each day, between 0800 and 1800 h, FABS received smartwatch notifications to break sitting with 3 min of low-to-moderate-intensity physical activity every 30 min. Glycemic control was assessed by oral glucose tolerance test (OGTT) and continuous glucose monitoring. Blood samples and vastus lateralis biopsies were taken for assessment of clinical chemistry and the skeletal muscle lipidome, respectively. Compared with baseline, FABS increased median steps by 744 [IQR (483-951)] and walking time by 10.4 [IQR (2.2-24.6)] min/day. Other indices of activity/sedentary behavior were unchanged. Glucose tolerance and average 24-h glucose curves were also unaffected. However, mean (±SD) fasting glucose levels [-0.34 (±0.37) mmol/L] and daily glucose variation [%CV; -2% (±2.2%)] reduced in FABS, suggesting a modest benefit for glycemic control that was most robust at higher volumes of daily activity. Clinical chemistry and the skeletal muscle lipidome were largely unperturbed, although two long-chain triglycerides increased 1.25-fold in FABS, postintervention. All parameters remained stable in control. Under free-living conditions, FABS lowered fasting glucose and glucose variability. Larger volumes of activity breaks from sitting may be required to promote greater health benefits.NEW & NOTEWORTHY Under free-living conditions, breaking sitting modestly increased activity behavior. Breaking sitting was insufficient to modulate glucose tolerance or the skeletal muscle lipidome. Activity breaks reduced fasting blood glucose levels and daily glucose variation compared with baseline, with a tendency to also decrease fasting LDLc. This intervention may represent the minimal dose for breaking sedentary behavior, with larger volumes of activity possibly required to promote greater health benefits.

Sedentary behaviour, physical activity and cardiometabolic health in highly trained athletes: A systematic review and meta-analysis

Prolonged periods of sedentary time appear to increase the risk for the development of several chronic conditions and all-cause mortality, even when moderate-to-vigorous physical activity (MVPA) is taken into consideration. However, whether the beneficial health effects of MVPA in highly active individuals remain present when leisure time is spent sedentary remains speculative. Therefore, we systematically evaluated off-training sedentary behaviour and physical activity levels in athletes. Studies were collected from four bibliographic databases (PubMed, Embase, Web of Science and The Cochrane Central Register of Controlled Trials). Studies were eligible for inclusion if they evaluated sedentary behaviour and physical activity levels among athletes. Data from athletes were compared with the general population and pooled using a random-effects model. After deduplication 3104 were identified of which 13 studies met inclusion criteria. Compared to the general population, athletes spent significantly more time in sedentary behaviour (+79 min/day; 95% confidence interval [CI]: [41, 65] min/day; p<0.001). In addition, athlete individuals spent less time in light intensity physical activity (-92 min/day; 95% CI: [-117, -66] min/day; p<0.001) and had increased levels of MVPA (+62 min/day; 95% CI: [38, 85] min/day; p<0.001) compared to the general population. Athletes exceed the average time spend sedentary per day and make them even more sedentary compared to the general population.

Frequency of Interruptions to Sitting Time: Benefits for Postprandial Metabolism in Type 2 Diabetes

OBJECTIVE

To determine whether interrupting sitting with brief bouts of simple resistance activities (SRAs) at different frequencies improves postprandial glucose, insulin, and triglycerides in adults with medication-controlled type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

Participants (n = 23, 10 of whom were female, with mean ± SD age 62 ± 8 years and BMI 32.7 ± 3.5 kg · m^-2) completed a three-armed randomized crossover trial (6- to 14-day washout): sitting uninterrupted for 7 h (SIT), sitting with 3-min SRAs (half squats, calf raises, gluteal contractions, and knee raises) every 30 min (SRA3), and sitting with 6-min SRAs every 60 min (SRA6). Net incremental areas under the curve (iAUC_net) for glucose, insulin, and triglycerides were compared between conditions.

RESULTS

Glucose and insulin 7-h iAUC_net were attenuated significantly during SRA6 (glucose 17.0 mmol · h · L^-1, 95% CI 12.5, 21.4; insulin 1,229 pmol · h · L^-1, 95% CI 982, 1,538) in comparison with SIT (glucose 21.4 mmol · h · L^-1, 95% CI 16.9, 25.8; insulin 1,411 pmol · h · L^-1, 95% CI 1,128, 1,767; P < 0.05) and in comparison with SRA3 (for glucose only) (22.1 mmol · h · L^-1, 95% CI 17.7, 26.6; P = 0.01) No significant differences in glucose or insulin iAUC_net were observed in comparison of SRA3 and SIT. There was no statistically significant effect of condition on triglyceride iAUC_net.

CONCLUSIONS

In adults with medication-controlled T2D, interrupting prolonged sitting with 6-min SRAs every 60 min reduced postprandial glucose and insulin responses. Other frequencies of interruptions and potential longer-term benefits require examination to clarify clinical relevance.

Gravity Threshold and Dose Response Relationships: Health Benefits Using a Short Arm Human Centrifuge

Purpose

Increasing the level of gravity passively on a centrifuge, should be equal to or even more beneficial not only to astronauts living in a microgravity environment but also to patients confined to bed. Gravity therapy (GT) may have beneficial effects on numerous conditions, such as immobility due to neuromuscular disorders, balance disorders, stroke, sports injuries. However, the appropriate configuration for administering the Gz load remains to be determined.

Methods

To address these issues, we studied graded G-loads from 0.5 to 2.0g in 24 young healthy, male and female participants, trained on a short arm human centrifuge (SAHC) combined with mild activity exercise within 40–59% MHR, provided by an onboard bicycle ergometer. Hemodynamic parameters, as cardiac output (CO), stroke volume (SV), mean arterial pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were analyzed, as well as blood gas analysis. A one-way repeated measures ANOVA and pairwise comparisons were conducted with a level of significance p < 0.05.

Results

Significant changes in heart rate variability (HRV) and its spectral components (Class, Fmax, and VHF) were found in all g loads when compared to standing (p < 0.001), except in 1.7 and 2.0g. There were significant changes in CO, cardiac index (CI), and cardiac power (CP) (p < 0.001), and in MAP (p = 0.003) at different artificial gravity (AG) levels. Dose-response curves were determined based on statistically significant changes in cardiovascular parameters, as well as in identifying the optimal G level for training, as well as the optimal G level for training. There were statistically significant gender differences in Cardiac Output/CO (p = 0.002) and Cardiac Power/CP (p = 0.016) during the AG training as compared to standing. More specifically, these cardiovascular parameters were significantly higher for male than female participants. Also, there was a statistically significant (p = 0.022) gender by experimental condition interaction, since the high-frequency parameter of the heart rate variability was attenuated during AG training as compared to standing but only for the female participants (p = 0.004).

Conclusion

The comprehensive cardiovascular evaluation of the response to a range of graded AG loads, as compared to standing, in male and female subjects provides the dose-response framework that enables us to explore and validate the usefulness of the centrifuge as a medical device. It further allows its use in precisely selecting personalized gravity therapy (GT) as needed for treatment or rehabilitation of individuals confined to bed.

Walking for subjects with type 2 diabetes: a systematic review and joint AMD/SID/SISMES evidence-based practical guideline

Aims

Regular exercise is considered a cornerstone in the management of type 2 diabetes mellitus (T2DM). It improves glucose control and cardiovascular risk factors, contributes to weight loss, and also improves general well-being, likely playing a role in the prevention of chronic complications of diabetes. However, compliance to exercise recommendations is generally inadequate in subjects with T2DM. Walking is the most ancestral form of physical activity in humans, easily applicable in daily life. It may represent, in many patients, a first simple step towards lifestyle changes. Nevertheless, while most diabetic patients do not engage in any weekly walking, exercise guidelines do not generally detail how to improve its use. The aims of this document are to conduct a systematic review of available literature on walking as a therapeutic tool for people with T2DM, and to provide practical, evidence-based clinical recommendations regarding its utilization in these subjects.

Data synthesis

Analysis of available RCTs proved that regular walking training, especially when supervised, improves glucose control in subjects with T2DM, with favorable effects also on cardiorespiratory fitness, body weight, and blood pressure. Moreover, some recent studies have shown that even short bouts of walking, used for breaking prolonged sitting, can ameliorate glucose profiles in diabetic patients with sedentary behavior.

Conclusions

There is sufficient evidence to recognize that walking is a useful therapeutic tool for people with T2DM. This document discusses theoretical and practical issues for improving its use.

Effects of sedentary behaviour interventions on biomarkers of cardiometabolic risk in adults: systematic review with meta-analyses

CONTEXT/PURPOSE

Observational and acute laboratory intervention research has shown that excessive sedentary time is associated adversely with cardiometabolic biomarkers. This systematic review with meta-analyses synthesises results from free living interventions targeting reductions in sedentary behaviour alone or combined with increases in physical activity.

METHODS

Six electronic databases were searched up to August 2019 for sedentary behaviour interventions in adults lasting for ≥7 days publishing cardiometabolic biomarker outcomes covering body anthropometry, blood pressure, glucose and lipid metabolism, and inflammation (54 studies). The pooled effectiveness of intervention net of control on 15 biomarker outcomes was evaluated using random effects meta-analyses in the studies with control groups not providing other relevant interventions (33 studies; 6-25 interventions analysed).

RESULTS

Interventions between 2 weeks and <6 months in non-clinical populations from North America, Europe and Australia comprised much of the evidence base. Pooled effects revealed small, significant (p<0.05) beneficial effects on weight (≈ -0.6 kg), waist circumference (≈ -0.7 cm), percentage body fat (≈ -0.3 %), systolic blood pressure (≈ -1.1 mm Hg), insulin (≈ -1.4 pM) and high-density lipoprotein cholesterol (≈ 0.04 mM). Pooled effects on the other biomarkers (p>0.05) were also small, and beneficial in direction except for fat-free mass (≈ 0.0 kg). Heterogeneity ranged widely (I2=0.0-72.9).

CONCLUSIONS

Our review of interventions targeting sedentary behaviour reductions alone, or combined with increases in physical activity, found evidence of effectiveness for improving some cardiometabolic risk biomarkers to a small degree. There was insufficient evidence to evaluate inflammation or vascular function. Key limitations to the underlying evidence base include a paucity of high-quality studies, interventions lasting for ≥12 months, sensitive biomarkers and clinical study populations (eg, type 2 diabetes).

PROSPERO TRIAL REGISTRATION NUMBER

CRD42016041742.

Periodized versus classic exercise therapy in Multiple Sclerosis: a randomized controlled trial

BACKGROUND

Periodizing exercise interventions in Multiple Sclerosis (MS) shows good high intensity exercise training adherence. Whether this approach induces comparable training adaptations with respect to exercise capacity, body composition and muscle strength compared to conventional, linear progressive training programs however is not known.

METHODS

Thirty-one persons with MS (all phenotypes, mean EDSS 2.3±1.3) were randomized into a twelve-week periodized (MS_PER, n=17) or a classic endurance (MS_CLA, n=14) training program. At baseline (PRE), exercise capacity (maximal exercise test, VO_2max), body composition (DEXA) and muscle strength (Biodex®) were assessed. Classic, moderate intensity endurance training (60-80% HR_max, 5 training sessions/2w, 60min/session) was performed on a stationary bicycle. Periodized exercise included 4 recurrent 3-week cycles of alternated endurance training (week 1: endurance training as described above), high intense exercise (week 2: 3 sessions/w, 3 × 20s all-out sprints, 10min/session) and recovery weeks (week 3: one sprint session as described above). POST measurements were performed similar to baseline. Total exercise volume of both programs was expressed as total peak-effort training minutes.

RESULTS

For MS_CLA, total exercise volume included 1728 total peak-effort training minutes, whereas MS_PER included only 736. Despite this substantially reduced training volume, twelve weeks of periodized training significantly (p<0.05) improved VO_2max (+14%, p=0.001), workload (+20%) and time until exhaustion (+25%). Classic training significantly (p<0.05) improved workload (+10%) and time until exhaustion (+17%), but not VO_2max (+5%, p=0.131). Pre-post improvements for VO_2max were significantly higher in MS_PER compared to MS_CLA (p=0.046).

CONCLUSION

These data show that despite substantially lower training time (57% less peak-effort training minutes), 12 weeks of periodized exercise training in persons with MS seems to induce larger improvements in parameters of exercise capacity compared to classic endurance training. We therefore recommend to further investigate the effect of training periodization on various functional rehabilitation measures in MS.

Reducing Sitting Time in Obese Older Adults: The I-STAND Randomized Controlled Trial

BACKGROUND

The authors tested the efficacy of the "I-STAND" intervention for reducing sitting time, a novel and potentially health-promoting approach, in older adults with obesity.

METHODS

The authors recruited 60 people (mean age = 68 ± 4.9 years, 68% female, 86% White; mean body mass index = 35.4). The participants were randomized to receive the I-STAND sitting reduction intervention (n = 29) or healthy living control group (n = 31) for 12 weeks. At baseline and at 12 weeks, the participants wore activPAL devices to assess sitting time (primary outcome). Secondary outcomes included fasting glucose, blood pressure, and weight. Linear regression models assessed between-group differences in the outcomes.

RESULTS

The I-STAND participants significantly reduced their sitting time compared with the controls (-58 min per day; 95% confidence interval [-100.3, -15.6]; p = .007). There were no statistically significant changes in the secondary outcomes.

CONCLUSION

I-STAND was efficacious in reducing sitting time, but not in changing health outcomes in older adults with obesity.

Walking for subjects with type 2 diabetes: A systematic review and joint AMD/SID/SISMES evidence-based practical guideline

AIMS

Regular exercise is considered a cornerstone in the management of type 2 diabetes mellitus (T2DM). It improves glucose control and cardiovascular risk factors, contributes to weight loss, and also improves general well-being, likely playing a role in the prevention of chronic complications of diabetes. However, compliance to exercise recommendations is generally inadequate in subjects with T2DM. Walking is the most ancestral form of physical activity in humans, easily applicable in daily life. It may represent, in many patients, a first simple step towards lifestyle changes. Nevertheless, while most diabetic patients do not engage in any weekly walking, exercise guidelines do not generally detail how to improve its use. The aims of this document are to conduct a systematic review of available literature on walking as a therapeutic tool for people with T2DM, and to provide practical, evidence-based clinical recommendations regarding its utilization in these subjects.

DATA SYNTHESIS

Analysis of available RCTs proved that regular walking training, especially when supervised, improves glucose control in subjects with T2DM, with favorable effects also on cardiorespiratory fitness, body weight and blood pressure. Moreover, some recent studies have shown that even short bouts of walking, used for breaking prolonged sitting, can ameliorate glucose profiles in diabetic patients with sedentary behavior.

CONCLUSIONS

There is sufficient evidence to recognize that walking is a useful therapeutic tool for people with T2DM. This document discusses theoretical and practical issues for improving its use. This article is co-published in the journals Sport Sciences for Health and Nutrition, Metabolism and Cardiovascular Diseases.

Effect of Walking on Sand with Dietary Intervention in OverweightType 2 DiabetesMellitusPatients: A Randomized Controlled Trial

(1) Background: The primary goal of this study was to assess the effect of sand walking on Hemoglobin A1c (HbA1c), Body Mass Index (BMI), waist circumference, and quality of life among individuals with Type-2 Diabetes Mellitus (T2DM). (2) Methods: A randomized-controlled design was conducted on 66 overweight participants suffering from T2DM. Participants were randomly allocated to sand walking (SW) (n = 33) and normal walking (NW) (n = 33) groups. Participants performed moderate-intensity walking for 30 min, 3 times a week for 4 months. Participants walking on sand had statistically significant mean scores for HbA1c, BMI, waist circumference and quality of life((M = 7.32, SD = 0.47),(M = 25.77, SD = 1.366),(M = 92.94, SD = 2.59), (M = 91.48, SD = 34.08)) than those walking on leveled surface ((M = 8.38, SD = 0.77),t(52.8) = −6.73, p = 0.003, (M = 26.80, SD = 1.38), t(64) = −3.05, p = 0.001,(M = 98.12, SD = 2.16.3), t(64) = −3.75, p = 0.001, (M = 112, SD = 33.7), t(64) = −2.45, p = 0.017)respectively. (3) Conclusions: Regular SW with a healthy dietary regime for 4 months led to a statistically significant difference in HbA1c, BMI, waist circumference, and quality of life as compared to NW group.

Changes in sedentary behaviour in European Union adults between 2002 and 2017

BACKGROUND

Sedentary behaviour (SB) has been identified as an important mortality risk factor. Health organizations have recognised SB as a public health challenge with major health, social, and economic consequences. Researchers have alerted the need to develop specific strategies, to monitor, prevent, and reduce SB. However, there is no systematic analysis of the SB changes in European Union adults. We aimed to examine SB changes between 2002 and 2017 in the European Union (EU) adult population.

METHODS

SB prevalence (>4h30mins of sitting time/day) of 96,004 adults as a whole sample and country-by-country was analysed in 2002, 2005, 2013, and 2017 of the Sport and Physical Activity EU Special Eurobarometers' data. The SB question of a modified version of the International Physical Activity Questionnaire was considered. SB prevalence between countries and within years was analysed with a χ2 test, and SB between genders was analysed with the Z-Score test for two population proportions.

RESULTS

An association between the SB prevalence and the years was found (p <  0.001), with increases for the whole sample (2002: 49.3%, 48.5-50.0 95% confidence interval (CI); 2017: 54.5%, 53.9-55.0 95% CI) and men (2002: 51.2%, 50.0-52.4 95% CI; 2017: 55.8%, 55.0-56.7 95% CI) and women (2002: 47.6%, 46.6-48.7 95% CI; 2017: 53.4%, 52.6-54.1 95% CI) separately. The adjusted standardised residuals showed an increase in the observed prevalence versus the expected during 2013 and 2017 for the whole sample and women and during 2017 for men. For all years, differences were observed in the SB prevalence between countries for the whole sample, and men and women separately (p <  0.001). Besides, the SB prevalence was always higher in men versus women in the overall EU sample (p <  0.001).

CONCLUSIONS

SB prevalence increased between 2002 and 2017 for the EU as a whole and for both sexes separately. Additionally, differences in SB prevalence were observed for all years between EU countries in the whole sample and both sexes separately. Lastly, SB was consistently higher in men than women. These findings reveal a limited impact of current policies and interventions to tackle SB at the EU population level.

Walking Time Is Associated With Hippocampal Volume in Overweight and Obese Office Workers

Objectives: To investigate the long-term effects on cognition and brain function after installing treadmill workstations in offices for 13 months.

Methods: Eighty healthy overweight or obese office workers aged 40–67 years were individually randomized to an intervention group, receiving a treadmill workstation and encouraging emails, or to a control group, continuing to work as usual. Effects on cognitive function, hippocampal volume, prefrontal cortex (PFC) thickness, and circulating brain-derived neurotrophic factor (BDNF) were analyzed. Further, mediation analyses between changes in walking time and light-intensity physical activity (LPA) on changes in BDNF and hippocampal volume between baseline and 13 months, and multivariate analyses of the baseline data with percentage sitting time as the response variable, were performed.

Results: No group by time interactions were observed for any of the outcomes. In the mediation analyses, positive associations between changes in walking time and LPA on changes in hippocampal volume were observed, although not mediated by changes in BDNF levels. In the multivariate analyses, a negative association between percentage sitting time and hippocampal volume was observed, however only among those older than 51 years of age.

Conclusion: Although no group by time interactions were observed, our analyses suggest that increased walking and LPA may have positive effects on hippocampal volume and that sedentary behavior is associated with brain structures of importance for memory functions.

Trial Registration: www.ClinicalTrials.gov as NCT01997970.

Sedentary time and activity behaviors after stroke rehabilitation: Changes in the first 3 months home

BACKGROUND

Sedentary time is prevalent following stroke, limiting functional improvement, and increasing cardiovascular risk. At discharge we examined: 1) change in sedentary time and activity over the following 3 months' and 2) physical, psychological or cognitive factors predicting any change. A secondary aim examined cross-sectional associations between factors and activity at 3 months.

METHODS

People with stroke (n = 34) were recruited from two rehabilitation units. An activity monitor (ActivPAL3) was worn for 7 days during the first week home and 3 months later. Factors examined included physical, psychological, and cognitive function. Linear mixed models (adjusted for waking hours) were used to examine changes in sedentary time, walking, and step count over time. Interaction terms between time and each factor were added to the model to determine if they modified change over time. Linear regression was performed to determine factors cross-sectionally associated with 3-month activity.

RESULTS

ActivPAL data were available at both time points for 28 (82%) participants (mean age 69 [SD 12] years). At 3 months, participants spent 39 fewer minutes sedentary (95%CI -70,-8 p = .01), 21 minutes more walking (95%CI 2,22 p = .02) and completed 1112 additional steps/day (95%CI 268,1956 p = .01), compared to the first week home. No factors predicted change in activity. At 3 months, greater depression (β 22 mins (95%CI 8,36) p = .004) and slower gait speed (β - 43 mins 95%CI -59,-27 p ≤ 0.001) were associated with more sedentary time and less walking activity, respectively.

CONCLUSIONS

Sedentary time reduced and walking activity increased between discharge home and 3 months later. Interventions targeting mood and physical function may warrant testing to reduce sedentary behavior 3 months following discharge.

A Case for Promoting Movement Medicine: Preventing Disability in the LIFE Randomized Controlled Trial

BACKGROUND

The movement profile of older adults with compromised function is unknown, as is the relationship between these profiles and the development of major mobility disability (MMD)-a critical clinical outcome. We first describe the dimensions of movement in older adults with compromised function and then examine whether these dimensions predict the onset of MMD.

METHODS

Older adults at risk for MMD (N = 1,022, mean age = 78.7 years) were randomized to receive a structured physical activity intervention or health education control. We assessed MMD in 6-month intervals (average follow-up of 2.2 years until incident MMD), with activity assessed at baseline, 6-, 12- and 24-month follow-up via accelerometry.

RESULTS

A principal components analysis of 11 accelerometer-derived metrics yielded three components representing lifestyle movement (LM), extended bouts of moderate-to-vigorous physical activity (MVPA), and stationary body posture. LM accounted for the greatest proportion of variance in movement (53%). Within health education, both baseline LM (HR = 0.74; 95% CI 0.62 to 0.88) and moderate-to-vigorous physical activity (HR = 0.69; 95% CI 0.54 to 0.87) were associated with MMD, whereas only LM was associated with MMD within physical activity (HR = 0.74; 95% CI 0.61 to 0.89). There were similar nonlinear relationships present for LM in both physical activity and health education (p < .04), whereby risk for MMD was lower among individuals with higher levels of LM.

CONCLUSIONS

Both LM and moderate-to-vigorous physical activity should be central in treatment regimens for older adults at risk for MMD.

TRIAL REGISTRATION

clinicaltrials.gov Identifier NCT01072500.

Are all Sedentary Behaviors Equal? An Examination of Sedentary Behavior and Associations with Indicators of Disease Risk Factors in Women

Sedentary behavior increases risk for non-communicable diseases; associations may differ within different contexts (e.g., leisure time, occupational). This study examined associations between different types of sedentary behavior and disease risk factors in women, using objectively measured accelerometer-derived sedentary data. A validation study (n = 20 women) classified sedentary behavior into four categories: lying down; sitting (non-active); sitting (active); standing. A cross-sectional study (n = 348 women) examined associations between these classifications and disease risk factors (body composition, metabolic, inflammatory, blood lipid variables). Participants spent an average of 7 h 42 min per day in sedentary behavior; 58% of that time was classified as non-active sitting and 26% as active sitting. Non-active sitting showed significant (p ≤ 0.001) positive correlations with BMI (r = 0.244), body fat percent (r = 0.216), body mass (r = 0.236), fat mass (r = 0.241), leptin (r = 0.237), and negative correlations with HDL-cholesterol (r = −0.117, p = 0.031). Conversely, active sitting was significantly (p ≤ 0.001) negatively correlated with BMI (r = −0.300), body fat percent (r = −0.249), body mass (r = −0.305), fat mass (r = −0.320), leptin (r = −0.259), and positively correlated with HDL-cholesterol (r = 0.115, p = 0.035). In summary, sedentary behavior can be stratified using objectively measured accelerometer-derived activity data. Subsequently, different types of sedentary behaviors may differentially influence disease risk factors. Public health initiatives should account for sedentary classifications when developing sedentary behavior recommendations.

Sitting, squatting, and the evolutionary biology of human inactivity

Recent work suggests human physiology is not well adapted to prolonged periods of inactivity, with time spent sitting increasing cardiovascular disease and mortality risk. Health risks from sitting are generally linked with reduced levels of muscle contractions in chair-sitting postures and associated reductions in muscle metabolism. These inactivity-associated health risks are somewhat paradoxical, since evolutionary pressures tend to favor energy-minimizing strategies, including rest. Here, we examined inactivity in a hunter-gatherer population (the Hadza of Tanzania) to understand how sedentary behaviors occur in a nonindustrial economic context more typical of humans' evolutionary history. We tested the hypothesis that nonambulatory rest in hunter-gatherers involves increased muscle activity that is different from chair-sitting sedentary postures used in industrialized populations. Using a combination of objectively measured inactivity from thigh-worn accelerometers, observational data, and electromygraphic data, we show that hunter-gatherers have high levels of total nonambulatory time (mean ± SD = 9.90 ± 2.36 h/d), similar to those found in industrialized populations. However, nonambulatory time in Hadza adults often occurs in postures like squatting, and we show that these "active rest" postures require higher levels of lower limb muscle activity than chair sitting. Based on our results, we introduce the Inactivity Mismatch Hypothesis and propose that human physiology is likely adapted to more consistently active muscles derived from both physical activity and from nonambulatory postures with higher levels of muscle contraction. Interventions built on this model may help reduce the negative health impacts of inactivity in industrialized populations.

Sedentary Behavior and Chronic Disease: Mechanisms and Future Directions

Background: Recent updates to physical activity guidelines highlight the importance of reducing sedentary time. However, at present, only general recommendations are possible (ie, “Sit less, move more”). There remains a need to investigate the strength, temporality, specificity, and dose–response nature of sedentary behavior associations with chronic disease, along with potential underlying mechanisms. Methods: Stemming from a recent research workshop organized by the Sedentary Behavior Council themed “Sedentary behaviour mechanisms—biological and behavioural pathways linking sitting to adverse health outcomes,” this paper (1) discusses existing challenges and scientific discussions within this advancing area of science, (2) highlights and discusses emerging areas of interest, and (3) points to potential future directions. Results: A brief knowledge update is provided, reflecting upon current and evolving thinking/discussions, and the rapid accumulation of new evidence linking sedentary behavior to chronic disease. Research “action points” are made at the end of each section—spanning from measurement systems and analytic methods, genetic epidemiology, causal mediation, and experimental studies to biological and behavioral determinants and mechanisms. Conclusion: A better understanding of whether and how sedentary behavior is causally related to chronic disease will allow for more meaningful conclusions in the future and assist in refining clinical and public health policies/recommendations.

Effect of exercise referral schemes upon health and well-being: initial observational insights using individual patient data meta-analysis from the National Referral Database

Objectives

To examine if exercise referral schemes (ERSs) are associated with meaningful changes in health and well-being in a large cohort of individuals throughout England, Scotland, and Wales from the National Referral Database.

Methods

Data were obtained from 23 731 participants from 13 different ERSs lasting 6 weeks to 3 months. Changes from pre- to post-ERS in health and well-being outcomes were examined including body mass index (BMI), blood pressure (systolic (SBP) and diastolic (DBP)), resting heart rate (RHR), short Warwick Edinburgh Mental Wellbeing Scale (SWEMWBS), WHO Well-Being Index (WHO-5), Exercise Related Quality of Life scale (ERQoL), and Exercise Self-Efficacy Scale (ESES). Two-stage individual patient data meta-analysis was used to generate effect estimates.

Results

Estimates (95% CIs) revealed statistically significant changes occurred compared with point nulls for BMI (−0.55 kg.m2 (−0.69 to −0.41)), SBP (−2.95 mmHg (−3.97 to −1.92)), SWEMWBS (2.99 pts (1.61 to 4.36)), WHO-5 (8.78 pts (6.84 to 10.63)), ERQoL (15.26 pts (4.71 to 25.82)), and ESES (2.58 pts (1.76 to 3.40)), but not RHR (0.22 fc (−1.57 to 1.12)) or DBP (−0.93 mmHg (−1.51 to −0.35)). However, comparisons of estimates (95% CIs) against null intervals suggested the majority of outcomes may not improve meaningfully.

Conclusions

We considered whether meaningful health and well-being changes occur in people who are undergoing ERSs. These results demonstrate that, although many health and well-being outcomes improved, the changes did not achieve meaningful levels. This suggests the need to consider the implementation of ERSs more critically to discern how to maximise their effectiveness.

Increasing physical activity in adult women with Prader-Willi syndrome: A transferability study

BACKGROUND

The present authors aimed (a) to objectively quantify spontaneous physical activity (PA) in adult patients with Prader-Willi syndrome (PWS) and (b) to evaluate the transferability of a home-based exercise training programme in these patients.

METHOD

Physical activity was compared between 10 adult women with PWS (PWS group) and 20 adult women with non-syndromic obesity (CON group, for cross-sectional comparison). In the PWS group, PA, body composition, walking capacity, quality of life and eating behaviour were then compared before and after a 16-week supervised exercise programme.

RESULTS

The PWS group displayed lower PA and higher sedentary time compared to the CON group. Median attendance to exercise sessions reached 100% (Q1-Q3: 97%-100%) sessions. Moderate-to-vigorous PA and walking capacity increased after the programme without significant effect on body composition.

CONCLUSION

Supervised home-based exercise sessions are an effective strategy to improve PA in women with PWS who are less active than women matched for adiposity.

Biochemical Data and Metabolic Profiles of Male Exclusive Narghile Smokers (ENSs) Compared With Apparently Healthy Nonsmokers (AHNSs)

Studies evaluating the metabolic profiles of ENSs are scarce and presented controversial conclusions. This study aimed to compare the metabolic profiles of ENSs' and AHNSs' groups. Males aged 25-45 years and free from a known history of metabolic and/or cardiovascular diseases were included. According to the smoking status, two groups of ENSs and AHNSs were identified. Body mass index (BMI, kg/m2), waist circumference (WC, cm), systolic and diastolic blood pressures (SBP, DBP, mmHg), fasting blood data in mmol/L (blood glycemia [FBG], triglycerides [TG], total cholesterol [TC], high- and low- density lipoprotein cholesterol [HDL-C, LDL-C]) and obesity status were evaluated. The metabolic syndrome (MetS) was defined according to the 2006 International Diabetes Federation (IDF) recommendations. Data were expressed as mean ± standard deviation ( SD) or percentages. Compared to the AHNSs' group ( n = 29), the ENSs' one ( n = 29) had (a) higher values of BMI (26.5 ± 2.3 vs. 28.2 ± 3.6), WC (95 ± 7 vs. 100 ± 10), and TG (1.22 ± 0.40 vs. 1.87 ± 0.85); and (b) included a lower percentage of males having low HDL-C (82.7% vs. 62.0%), and higher percentages of males having obesity (6.9% vs. 37.9%) or hypertriglyceridemia (10.7% vs. 51.7%). Both the ENSs' and AHNSs' groups: (a) had similar values of FBG (5.38 ± 0.58 vs. 5.60 ± 0.37), TC (4.87 ± 1.16 vs. 4.36 ± 0.74), HDL-C (0.92 ± 0.30 vs. 0.82 ± 0.21), LDL-C (3.09 ± 0.98 vs. 2.92 ± 0.77), SBP (117 ± 9 vs. 115 ± 8), and DBP (76 ± 6 vs. 73 ± 7); and (b) included similar percentages of males having normal weight (17.2% vs. 31.0%); overweight (44.8% vs. 62.1%); android obesity (79.3% vs. 59.6%), hypertension (10.3% vs. 10.3%), hyperglycemia (37.9% vs. 48.2%), and MetS (51.7% vs. 34.5%). There is a need to monitor narghile use among male metabolic patients since it alters some components of the MetS.