Light-intensity Activity Research Articles

Accelerometer-measured dose-response for physical activity, sedentary time, and mortality in US adults

Moderate-to-vigorous-intensity physical activity is recommended to maintain and improve health, but the mortality benefits of light activity and risk for sedentary time remain uncertain. Using accelerometer-based measures, we 1) described the mortality dose-response for sedentary time and light- and moderate-to-vigorous-intensity activity using restricted cubic splines, and 2) estimated the mortality benefits associated with replacing sedentary time with physical activity, accounting for total activity. US adults (n = 4840) from NHANES (2003-2006) wore an accelerometer for ≤7 d and were followed prospectively for mortality. Proportional hazards models were used to estimate adjusted HRs and 95% CIs for mortality associations with time spent sedentary and in light- and moderate-to-vigorous-intensity physical activity. Splines were used to graphically present behavior-mortality relation. Isotemporal models estimated replacement associations for sedentary time, and separate models were fit for low- (<5.8 h total activity/d) and high-active participants to account for nonlinear associations. Over a mean of 6.6 y, 700 deaths occurred. Compared with less-sedentary adults (6 sedentary h/d), those who spent 10 sedentary h/d had 29% greater risk (HR: 1.29; 95% CI: 1.1, 1.5). Compared with those who did less light activity (3 h/d), those who did 5 h of light activity/d had 23% lower risk (HR: 0.77; 95% CI: 0.6, 1.0). There was no association with mortality for sedentary time or light or moderate-to-vigorous activity in highly active adults. In less-active adults, replacing 1 h of sedentary time with either light- or moderate-to-vigorous-intensity activity was associated with 18% and 42% lower mortality, respectively. Health promotion efforts for physical activity have mostly focused on moderate-to-vigorous activity. However, our findings derived from accelerometer-based measurements suggest that increasing light-intensity activity and reducing sedentary time are also important, particularly for inactive adults.

Objective measurement of free-living physical activity (performance) in lumbar spinal stenosis: are physical activity guidelines being met?

BackgroundResearch suggests that people with lumbar spinal stenosis (LSS) would benefit from increased physical activity. Yet, to date, we do not have disease-specific activity guidelines for LSS, and the nature of free-living physical activity (performance) in LSS remains unknown. LSS care providers could endorse the 2008 United States Physical Activity Guidelines; however, we do not know if this is realistic. The goal of the present study was to determine the proportion of individuals with LSS meeting the 2008 Guidelines. A secondary goal was to better understand the nature of physical performance in this population. Study DesignRetrospective study. Patient SamplePeople from the Lumbar Spinal Stenosis Accelerometry Database, all of whom have both radiographic and clinical LSS and are seeking various treatments for their symptoms. Outcome MeasuresSeven-day accelerometry (functional outcome) and demographics (self-reported). MethodsFor the present study, we analyzed only baseline data that were obtained before any new treatments. Patients with at least 4 valid days of baseline accelerometry data were included. We determined the proportion of individuals with LSS meeting the 2008 US Physical Activity Guidelines of at least 150 minutes of moderate-vigorous (MV) physical activity per week in bouts of 10 minutes or more. We also used the novel Physical Performance analysis designed by our group to determine time spent in varying intensities of activity. There are no conflicts of interest to disclose. ResultsWe analyzed data from 75 individuals with a mean age of 68 (SD 9), 37% of whom were male. Three people (4%) were considered Meeting Guidelines (at least 150 MV minutes/week), and 56 (75%) were considered Inactive with not even 1 MV minute/week. With the 10-minute bout requirement removed, 10 of 75 (13%) achieved the 150-minute threshold. The average time spent in sedentary activity was 82%, and of time spent in nonsedentary activity, 99.6% was in the light activity range. ConclusionsIn conclusion, the present study confirms that people with symptomatic LSS, neurogenic claudication, walking limitations, and LSS-related disability are extremely sedentary and are not meeting guidelines for physical activity. There is an urgent need for interventions aimed at reducing sedentary behavior and increasing the overall level of physical activity in LSS, not only to improve function but also to prevent diseases of inactivity. The present study suggests that reducing sedentary time, increasing time spent in light intensity activity, and increasing time spent in higher intensities of light activity may be appropriate as initial goals for exercise interventions in people with symptomatic LSS and neurogenic claudication, transitioning to moderate activity when appropriate. Results of the present study also demonstrate the importance of employing disease-specific measures for assessment of performance in LSS, and highlight the potential value of these methods for developing targeted and realistic goals for physical activity. Physical activity goals could be personalized using objective assessment of performance with accelerometry. The present study is one step toward a personalized medicine approach for people with LSS, focusing on increasing physical function.

Home-Based Exercise Supported by General Practitioner Practices: Ineffective in a Sample of Chronically Ill, Mobility-Limited Older Adults (the HOMEfit Randomized Controlled Trial).

To evaluate the effects a home-based exercise program delivered to ill and mobility-limited elderly individuals on physical function, physical activity, quality of life, fall-related self-efficacy, and exercise self-efficacy. Randomized controlled trial (ISRCTN Registry, Reg.-No. ISRCTN17727272). Fifteen general practitioner (GP) practices and participants' homes. Chronically ill and mobility-limited individuals aged 70 and older (N = 209). An exercise therapist delivered the experimental intervention-a 12-week multidimensional home-based exercise program integrating behavioral strategies-in individual counseling sessions at the GPs' practices and over the telephone. The control intervention focused on promoting light-intensity activities of daily living. Interventions took place between February 2012 and March 2013. The primary outcome was functional lower body strength (chair-rise test). Secondary outcomes were physical function (battery of motor tests), physical activity (step count), health-related quality of life (Medical Outcomes Study 8-item Short-Form Survey), fall-related (Falls Efficacy Scale-International Version), and exercise self-efficacy (Selbstwirksamkeit zur sportlichen Aktivitaet (SSA) scale). Postintervention differences between the groups were tested using analysis of covariance (intention to treat; adjusted for baseline value and GP practice; significance level P ≤ .05). Participants had a mean age ± standard deviation of 80 ± 5, 74% were female, 87% had three or more chronic diseases, and 54% used a walking aid. The difference (intention to treat; experimental minus control) between adjusted postintervention chair-rise times was -0.1 (95% confidence interval = -1.8-1.7). Differences for all secondary outcomes were also nonsignificant. The program was ineffective in the target population. Possibilities for improving the concept will have to be evaluated.

Seasonal changes in objectively measured sedentary behavior and physical activity in Japanese primary school children.

BackgroundThe recent prevalence of obesity in Japanese children is much higher compared to 1980. The present study compared daily sedentary behavior (SB) and physical activity (PA) between the school year and summer vacation in Japanese primary school children.MethodsParticipants were 98 Japanese boys (8.9 ± 1.8 years at baseline) and 111 girls (9.1 ± 1.8 years). SB and PA were measured in May (school term) and July/August (summer vacation), 2011. SB and PA were assessed using a triaxial accelerometer (Active style Pro HJA-350IT, Omron Healthcare) for 7 consecutive days. The average number of minutes spent in SB (no more than 1.5 metabolic equivalents (METs)), light intensity activity (LPA; more than 1.5 to less than 3.0 METs) and moderate-to-vigorous physical activity (MVPA; 3.0 METs or more), and step counts were calculated for each individual. Moreover, the determinants/moderators of changes in SB and PA were examined.ResultsDaily SB was significantly higher in the summer vacation than in the school year for both boys and girls (p < 0.05). Ambulatory and total LPA and MVPA, non-ambulatory LPA and step counts were lower in summer vacation in both genders (p < 0.001). Moreover, non-ambulatory MVPA was significantly lower in the summer vacation than in the school year for girls (p < 0.001). The decrease in non-ambulatory MVPA in boys and increase in SB in girls were significantly lower in those who participated in sports compared to those who did not (p < 0.040 or p < 0.033). The change in SB for boys was significantly associated with having a TV in the bedroom (p < 0.022).ConclusionsThese findings show that primary school children in Japan are less active in the summer vacation, as indicated by both higher SB and lower LPA and ambulatory MVPA in both genders. Moreover, the seasonal change in non-ambulatory MVPA for Japanese children was affected by gender. This study also suggests that sports participation and bedroom TV ownership may moderate seasonal changes in PA and SB. The results emphasize the need to take summer vacation into account when planning interventions aimed at decreasing SB or increasing PA in Japanese children.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3633-5) contains supplementary material, which is available to authorized users.

Validity and Reliability of Smartphone Applications for the Assessment of Walking and Running in Normal-weight and Overweight/Obese Young Adults.

The suitability of smartphone applications (apps) currently used to track walking/running may differ depending on a person's weight condition. This study aimed to examine the validity and reliability of apps for both normal-weight and overweight/obese young adults. Thirty normal-weight (aged 21.7 ± 1.0 years, BMI 21.3 ± 1.9 kg/m2) and 30 overweight/ obese young adults (aged 21.0 ± 1.4 years, BMI 28.6 ± 3.7 kg/m2) wore a smartphone and pedometer on their right hip while walking/running at 3 different intensities on treadmills. Apps was randomly assigned to each individual for measuring average velocity, step count, distance, and energy expenditure (EE), and these measurements were then analyzed. The apps were not accurate in counting most of the measured variables and data fell significantly lower in the parameters than those measured with standard-reference instruments in both light and moderate intensity activity among the normal-weight group. Among the overweight and obese group, the apps were not accurate in detecting velocity, distance, or EE during either light or vigorous intensities. The percentages of mean difference were 30.1% to 48.9%. Apps may not have sufficient accuracy to monitor important physical parameters of human body movement. Apps need to be developed that can, in particular, respond differently based on a person's weight status.

Associations Between Objectively Assessed Components of Physical Activity and Health-Related Fitness in 10- to 14-Year-Old Children.

Our aim was to investigate the association between different components of physical activity (PA) and health-related fitness in 10-to 14-year-old children. 241 children were recruited from 15 primary and 15 secondary schools. PA was assessed using the SenseWear Mini and an electronic diary. Health-related fitness was assessed using Eurofit and translated into indicators of body fatness, cardiorespiratory fitness and muscular fitness. Associations between PA intensity and physical fitness components were determined using multiple linear regression models adjusted for possible confounders and the contribution of PA domains per intensity categories was calculated. Associations between PA intensities and body fatness were low to moderate (|β| = 0.09 to 0.44), explaining up to 6% of the variance in boys and 17% in girls. For cardiorespiratory fitness, associations were higher (|β| = 0.17 to 0.56), with PA explaining up to 6% of the variance in boys and 31% in girls. Low-tomoderate associations (|β| = 0.06 to 0.43) were found for muscular fitness, with PA explaining up to 7% in boys and 13% in girls. Stronger associations were found for sedentary and light activities. Low-to-moderate associations between PA and fitness components were observed, with higher associations in girls. Sedentary and light intensity activity showed the strongest link with body fatness, cardiorespiratory fitness and muscular fitness.

Physical Activity and Sedentary Behavior Clustering: Segmentation to Optimize Active Lifestyles.

Increasingly the health impacts of physical inactivity are being distinguished from those of sedentary behavior. Nevertheless, deleterious health prognoses occur when these behaviors combine, making it a Public Health priority to establish the numbers and salient identifying factors of people who live with this injurious combination. Using an observational between-subjects design, a nonprobability sample of 22,836 participants provided data on total daily activity. A 2-step hierarchical cluster analysis identified the optimal number of clusters and the subset of distinguishing variables. Univariate analyses assessed significant cluster differences. High levels of sitting clustered with low physical activity. The Ambulatory & Active cluster (n = 6254) sat for 2.5 to 5 h·d(-1) and were highly active. They were significantly younger, included a greater proportion of males and reported low Indices of Multiple Deprivation compared with other clusters. Conversely, the Sedentary & Low Active cluster (n = 6286) achieved ≤60 MET·min·wk(-1) of physical activity and sat for ≥8 h·d(-1). They were the oldest cluster, housed the largest proportion of females and reported moderate Indices of Multiple Deprivation. Public Health systems may benefit from developing policy and interventions that do more to limit sedentary behavior and encourage light intensity activity in its place.

Frequent interruptions of sedentary time modulates contraction- and insulin-stimulated glucose uptake pathways in muscle: Ancillary analysis from randomized clinical trials

Epidemiological studies have observed associations between frequent interruptions of sitting time with physical activity bouts and beneficial metabolic outcomes, even in individuals who regularly exercise. Frequent interruptions to prolonged sitting reduce postprandial plasma glucose. Here we studied potential skeletal muscle mechanisms accounting for this improved control of glycemia in overweight adults under conditions of one day uninterrupted sitting and sitting interrupted with light-intensity or moderate-intensity walking every 20-min (n = 8); and, after three days of either uninterrupted sitting or light-intensity walking interruptions (n = 5). Contraction- and insulin-mediated glucose uptake signaling pathways as well as changes in oxidative phosphorylation proteins were examined. We showed that 1) both interventions reduce postprandial glucose concentration, 2) acute interruptions to sitting over one day stimulate the contraction-mediated glucose uptake pathway, 3) both acute interruptions to sitting with moderate-intensity activity over one day and light-intensity activity over three days induce a transition to modulation of the insulin-signaling pathway, in association with increased capacity for glucose transport. Only the moderate-intensity interruptions resulted in greater capacity for glycogen synthesis and likely for ATP production. These observations contribute to a mechanistic explanation of improved postprandial glucose metabolism with regular interruptions to sitting time, a promising preventive strategy for metabolic diseases.

Breaking Up Sedentary Behavior: Perceptions From Cancer Survivors.

Limited data exist on the benefits of, barriers to, and potential strategies to break up time spent sitting in cancer survivors. Such data will be meaningful given the consequences of prolonged sitting. The aim of this study was to conduct a mixed-method research study consisting of semistructured telephone interviews to identify recurrent themes associated with prolonged sitting in cancer survivors. African American breast cancer survivors (N = 31) were recruited from a local tumor registry. Telephone interviews were conducted and group consensus processes were used to identify recurrent themes. The a priori categories were benefits, barriers, and potential strategies to breaking up prolonged periods of sitting. Recurrent themes contributing most to prolonged sitting were leisure time interest (45%: eg, watching television and reading) and health challenges (27%: eg, pain and fatigue). Most (66%) women perceived improved health as benefits to breaking up time spent sitting. Nonetheless, many (41%) survivors reported health (eg, pain and fatigue) as the biggest challenge to interrupt time spent sitting. Engaging in light intensity activities (eg, staying active, keep moving) was the most commonly reported strategy for breaking up prolonged sitting. African American breast cancer survivors identified the benefits and barriers to breaking up time spent sitting as well as potential strategies to interrupt time-spent sitting. Clinicians are integral in promoting breaks from prolonged sitting throughout the initial phases of the cancer continuum. Successful studies will begin with early intervention in the clinical setting, with increasing intensity as survivors transition to the recovery phase.

Systematic review of the relationships between objectively measured physical activity and health indicators in school-aged children and youth

Moderate-to-vigorous physical activity (MVPA) is essential for disease prevention and health promotion. Emerging evidence suggests other intensities of physical activity (PA), including light-intensity activity (LPA), may also be important, but there has been no rigorous evaluation of the evidence. The purpose of this systematic review was to examine the relationships between objectively measured PA (total and all intensities) and health indicators in school-aged children and youth. Online databases were searched for peer-reviewed studies that met the a priori inclusion criteria: population (apparently healthy, aged 5-17 years), intervention/exposure/comparator (volumes, durations, frequencies, intensities, and patterns of objectively measured PA), and outcome (body composition, cardiometabolic biomarkers, physical fitness, behavioural conduct/pro-social behaviour, cognition/academic achievement, quality of life/well-being, harms, bone health, motor skill development, psychological distress, self-esteem). Heterogeneity among studies precluded meta-analyses; narrative synthesis was conducted. A total of 162 studies were included (204 171 participants from 31 countries). Overall, total PA was favourably associated with physical, psychological/social, and cognitive health indicators. Relationships were more consistent and robust for higher (e.g., MVPA) versus lower (e.g., LPA) intensity PA. All patterns of activity (sporadic, bouts, continuous) provided benefit. LPA was favourably associated with cardiometabolic biomarkers; data were scarce for other outcomes. These findings continue to support the importance of at least 60 min/day of MVPA for disease prevention and health promotion in children and youth, but also highlight the potential benefits of LPA and total PA. All intensities of PA should be considered in future work aimed at better elucidating the health benefits of PA in children and youth.

SenseWearMini and Actigraph GT3X Accelerometer Classification of Observed Sedentary and Light-Intensity Physical Activities in a Laboratory Setting.

Purpose: To compare the ability of SenseWear Mini (SWm) and Actigraph GT3X (AG3) accelerometers to differentiate between healthy adults' observed sedentary and light activities in a laboratory setting. Methods: The 22 participants (15 women, 7 men), ages 19 to 72 years, wore SWm and AG3 monitors and performed five sedentary and four light activities for 5 minutes each while observed in a laboratory setting. Performance was examined through comparisons of accuracy, sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. Correct identification of both types of activities was examined using area under the receiver operating characteristic curve (AUC). Results: Both monitors demonstrated excellent ability to identify sedentary activities (sensitivity>0.89). The SWm monitor was better at identifying light activities (specificity 0.61-0.71) than the AG3 monitor (specificity 0.27-0.47) and thus also showed a greater ability to correctly identify both sedentary and light activities (SWm AUC 0.84; AG3 AUC 0.62-0.73). Conclusions: SWm may be a more suitable monitor for detecting time spent in sedentary and light-intensity activities. This finding has clinical and research relevance for evaluation of time spent in lower intensity physical activities by sedentary adults.

Validation And Accuracy Of Fitbit Charge

Introduction: Wearable physical activity (PA) monitors (e.g., Fitbit®) have become increasingly popular for both researchers and lay people alike. Recent studies have reported several Fitbit® models correlate with research grade monitors; however none have reported on the accuracy of Fitbit® devices. Furthermore, noneto date have examined the Fitbit® Charge model. Purpose: The primary purpose of this pilot study was to compare step counts assessed by Fitbit® Charge and a research grade accelerometer (i.e. Actigraph®). The secondary purpose of this pilot study was to compare minutes spent in each PA intensity (light, moderate, vigorous) assessed by Fitbit® Charge and Actigraph®.Methods: Participants (n=8) wore Fitbit® Charge and Actigraph® monitors for seven days. All analyses compared step counts and PA intensity assessed by both types of monitors. First, validity was examined through a series of bivariate correlations. Next, accuracy was investigated by a series of paired sample t-tests compared step counts and minutes spent in light, moderate and vigorous intensity activity assessed by Fitbit® and Actigraph® monitors. Results: Significant correlations were found for all study outcomes (p’s < 0.05). Significant differences were observed for step counts on all days and weekly total step count (p’s < 0.05). Significant differences were found on most days for light PA intensity (p’s < 0.05) and moderate intensity activity (p’s < 0.05), and one day for vigorous PA (p = 0.007). Overall accumulated weekly total of minutes were significantly different (p =0.014). Conclusions: Our results indicate that there are high correlations between Fitbit® and Actigraph®monitors. However, our examination of accuracy of Fitbit® Charge devices revealed that these monitors may overestimate step counts, light intensity PA, and vigorous intensity PA. Further research is needed to determine if Fitbit® Charge devices accurately assess PA. Thus, researchers should use caution if considering use of Fitbit® Charge.; ;

Psychological Responses to Intermittent Physical Activity in Elementary School-Age Children

It is well-established that intermittent physical activity has a positive impact on children’s physical health. However, less is known regarding the psychological outcomes associated with intermittent activity in children. PURPOSE: The purpose of this study was two fold: (1) to examine the acute effects of intermittent physical activity on enjoyment and mood in children ages 7-11 years and (2) to determine the effects of exercise intensity on these psychological outcomes. METHODS: Thirty-nine children (18 males, 21 females; 33% overweight/obese; 59% non-white) completed four experimental conditions in random order: (1) 8 hours of sitting interrupted with 2-minute light-intensity activity breaks performed at 25% maximal heart rate (HRmax) every 18 minutes; (2) 8 hours of sitting interrupted with 2-minute moderate-intensity activity breaks (50% HRmax); (3) 8 hours of sitting interrupted with 2-minute high-intensity activity breaks (75% HRmax); and (4) 8 hours of sitting interrupted with 2 minutes of sedentary screen time. Throughout each condition, participants completed a total of 20 breaks. Enjoyment was assessed using the Physical Activity Enjoyment Scale during each condition day. The Subjective Exercise Experience Scale was used to analyze pre-post changes in mood responses to physical activity. RESULTS: Enjoyment was significantly higher during the low- (4.4±0.1), moderate- (4.4±0.1), and high-intensity (4.3±0.1) conditions, compared to the sedentary condition (4.1±0.1; p’s<0.05). Positive well-being was significantly higher during the low- (23.0±0.8) and moderate-intensity (23.4±0.7) conditions compared to the sedentary condition (21.8±1.0; p’s<0.05). Fatigue was significantly higher during the moderate- (9.7±0.7) and high-intensity (10.1±0.9) conditions, compared to the sedentary condition (8.2±0.8; p’s<0.01). Psychological distress significantly decreased between pre-post measures for all conditions (5.8±0.21 vs. 5.3±0.19; p<0.01). CONCLUSIONS: These data suggest intermittent physical activity elicits short-term psychological benefits in children. Future research should determine whether these benefits are sustained with repeated sessions of intermittent physical activity.

Bristol Girls Dance Project: a cluster randomised controlled trial of an after-school dance programme to increase physical activity among 11- to 12-year-old girls

BackgroundMany children do not meet UK physical activity (PA) guidelines. Girls are less active than boys, and the age-related decline in activity is steeper for girls. Dance is the favourite form of PA among adolescent girls in the UK. Participation in after-school dance classes could significantly contribute to girls’ PA. Therefore, after-school dance may be effective for increasing PA levels.ObjectivesTo determine the effectiveness and cost-effectiveness of a dance-based intervention to increase the objectively assessed mean weekday minutes of moderate- to vigorous-intensity physical activity (MVPA) of Year 7 girls (11- and 12-year olds) 1 year after baseline measurement.DesignTwo-arm cluster randomised controlled trial and economic evaluation. Year 7 girls in participant schools received a ‘taster’ session and were invited to participate. Up to 33 girls per school were able to participate. Schools were randomly assigned (equal numbers) to intervention or control arms.SettingA total of 18 mainstream secondary schools across greater Bristol.ParticipantsYear 7 girls in participating schools who could participate in physical education.InterventionNine intervention schools received an after-school dance intervention (40 × 75-minute sessions) underpinned by self-determination theory, which attempts to improve intrinsic motivation for being active, and delivered by external dance instructors. Control schools continued as normal.Main outcome measuresThe main outcome was accelerometer-assessed mean minutes of MVPA at T2. Measures were assessed at baseline (T0), the end of the intervention (T1) and at T0 + 52 weeks (T2).ResultsBaseline MVPA levels were high. A total of 508 girls were included in the primary analysis, which found no difference in weekday MVPA between trial arms. There was no effect on secondary accelerometer outcomes. Data were subjected to a per-protocol analysis and no effect was found. However, at T1, girls who attended dance classes had 4.61 minutes more of MVPA and 14.27 minutes more of light-intensity activity between 15.00 and 17.00 on the days on which they attended intervention sessions. The intervention was inexpensive at £73 per participant (£63 when excluding dance instructor travel) but was not cost-effective owing to the ineffectiveness of the intervention. The European Quality of Life-5 Dimensions Youth survey data were unresponsive to changes in the sample. The process evaluation reported that girls in attendance enjoyed the sessions, that exertion levels were low during sessions and that attendance was low and declined. Fidelity to the session-plan manual was low but theoretical fidelity (to self-determination theory) was good. Qualitative information provides information for improving future interventions.ConclusionsThe intervention was enjoyed by participants. However, there was no difference in the MVPA levels (which were high at baseline) of girls allocated to receive dance compared with girls receiving the control. High baseline MVPA levels indicate that the study appealed to an already active cohort and, therefore, may not have targeted those most in need of an intervention. Dance is an enjoyable activity for adolescent girls and could be further trialled as a means by which to increase PA. Research might consider the impact of dividing the intervention period into smaller blocks.Trial RegistrationCurrent Controlled Trials ISRCTN52882523.FundingThe National Institute for Health Research Public Health Research programme. The work was also undertaken with the support of the Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement (DECIPHer), a UK Clinical Research Collaboration (UKCRC) PHR Centre of Excellence. Joint funding (MR/KO232331/1) from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council, the Welsh Government and the Wellcome Trust, under the auspices of the UKCRC, is gratefully acknowledged. This study was designed and delivered in collaboration with the Bristol Randomised Trials Collaboration, a UKCRC Registered Clinical Trials Unit in receipt of NIHR Clinical Trials Unit support funding. All intervention costs were funded by the respective councils to which the participant schools were affiliated, namely North Somerset Council, Bristol City Council, and Bath and North East Somerset Council.

Physical activity metrics to predict function in older adults with lower extremity conditions: The Osteoarthritis Initiative

Purpose: Federal physical activity guidelines (moderate or vigorous activity acquired in bouts lasting at least 10 minutes {MV-bout] ≥150 minutes/week) are grounded in studies showing cardiovascular benefits. For adults with lower extremity conditions, maintaining-high or improving-low function may be a more immediate concern than cardiovascular health. The objective of this study is to evaluate if there are 1) Alternative physical activity metrics to consider for Persons who Maintain-high or Improve-low Lower Extremity (PerMILE) function, in contrast to the MV-bout metric which registers zero for a large portion of these adults and 2) Dosage related to subsequently improving-low or maintaining-high function among adults with lower extremity joint conditions. Methods: This longitudinal study evaluates adults with symptomatic (pain/aching/stiffness) or radiographic evidence of lower extremity joint conditions who participated in an accelerometer monitored physical activity substudy of the Osteoarthritis Initiative (OAI). Gait speed (n=1476) and self-reported SF-12 physical component score (PCS) function (n=1629) were measured at the substudy baseline (OAI 48 month clinical visit) and two years later. Good PerMILE function was separately determined for each measure based on staying in the best (i.e., maintaining-high) or moving to a better (i.e., improving-low) 2-year function quintile compared to baseline. To identify alternative metrics to predict good PerMILE function, the area under the receiver operating curve (AUC) from alternative physical activity metrics (sedentary, light intensity activity, all MV activity [All-MV], and all non-sedentary minutes/week) were compared to the reference MV-bout metric AUC. Classification tree analysis was used to identify metric minimum dosage thresholds which predict good PerMILE function. Results: This study evaluated adults aged 40–83 with baseline lower extremity conditions, of whom 34% and 38% had good 2-year PerMILE gait speed and SF-12 PCS function, respectively. All-MV weekly activity was the only metric investigated with significantly stronger predictive ability for good PerMILE function in both gait speed AUC (difference 0.05, 95% CI: 0.03, 0.07) and SF-12 PCS (difference: 0.02, 95% CI: 0.001, 0.03)assessments compared to the federal guideline MV-bout metric AUC (Table). Among adults with lower extremity conditions, doing at least 45 All-MV activity minutes per week had odds of 2.9 (95% CI: 2.4 to 3.6) for good PerMILE gait speed function compared to those with less All-MV activity. Adults doing at least 47 minutes All-MV activity minutes per week had odds of 1.9 (95% CI: 1.6 to 2.3) of good PerMILE SF-12 function compared to those with less. Conclusions: All MV activity (All-MV) minutes/week is a better metric than the traditional MV-bout metric to predict good PerMILE function for adults with lower extremity conditions. These findings support a minimum physical activity dose of at least 50 total MV minutes each week to subsequently maintain high function or improve low function.Tabled 1Table. Evaluation of Physical Activity Metrics to Predict Good PerMILE* FunctionGood 2-year PerMILE Gait Speed (n=1476)Physical Activity MetricArea Under Receiver Operating Curve (AUC) (95% CI)Metric AUC Compared to Reference (MV-bout) AUC Difference (95% CI)p-valueMV-bout time0.60 (0.57, 0.63)ReferenceSedentary time0.50 (0.47, 0.53)−0.09 (−0.14, −0.05)<.01Light activity time0.55 (0.52, 0.58)−0.05 (−0.09, −0.01)0.01All MV time0.65 (0.62, 0.67)0.05 (0.03, 0.07)<.01Non-sedentary time0.57 (0.54, 0.60)−0.02 (−0.06, 0.01)0.18Good 2-year PerMILE SF12 PGood 2-year PerMILE SF12 Physical Activity Component Score (n=1629)MV-bout time0.57 (0.54, 0.60)ReferenceSedentary time0.50 (0.47, 0.53)−0.07 (−0.12, −0.03)<.01Light activity time0.52 (0.49, 0.55)−0.05 (−0.09, −0.01)<.01All MV time0.59 (0.56, 0.62)0.02 (0.001, 0.03)0.03Non-sedentary time0.54 (0.51, 0.56)−0.03 (−0.07, −0.001)0.04*Persons who Maintain-high or Improve-low Lower Extremity. Open table in a new tab *Persons who Maintain-high or Improve-low Lower Extremity.

Objective measurement of free-living physical activity (performance) in lumbar spinal stenosis: are physical activity guidelines being met?

Abstract Background Research suggests that people with lumbar spinal stenosis (LSS) would benefit from increased physical activity. Yet, to date, we do not have disease-specific activity guidelines for LSS, and the nature of free-living physical activity (performance) in LSS remains unknown. LSS care providers could endorse the 2008 United States Physical Activity Guidelines; however, we do not know if this is realistic. The goal of the present study was to determine the proportion of individuals with LSS meeting the 2008 Guidelines. A secondary goal was to better understand the nature of physical performance in this population. Study Design Retrospective study. Patient Sample People from the Lumbar Spinal Stenosis Accelerometry Database, all of whom have both radiographic and clinical LSS and are seeking various treatments for their symptoms. Outcome Measures Seven-day accelerometry (functional outcome) and demographics (self-reported). Methods For the present study, we analyzed only baseline data that were obtained before any new treatments. Patients with at least 4 valid days of baseline accelerometry data were included. We determined the proportion of individuals with LSS meeting the 2008 US Physical Activity Guidelines of at least 150 minutes of moderate-vigorous (MV) physical activity per week in bouts of 10 minutes or more. We also used the novel Physical Performance analysis designed by our group to determine time spent in varying intensities of activity. There are no conflicts of interest to disclose. Results We analyzed data from 75 individuals with a mean age of 68 (SD 9), 37% of whom were male. Three people (4%) were considered Meeting Guidelines (at least 150 MV minutes/week), and 56 (75%) were considered Inactive with not even 1 MV minute/week. With the 10-minute bout requirement removed, 10 of 75 (13%) achieved the 150-minute threshold. The average time spent in sedentary activity was 82%, and of time spent in nonsedentary activity, 99.6% was in the light activity range. Conclusions In conclusion, the present study confirms that people with symptomatic LSS, neurogenic claudication, walking limitations, and LSS-related disability are extremely sedentary and are not meeting guidelines for physical activity. There is an urgent need for interventions aimed at reducing sedentary behavior and increasing the overall level of physical activity in LSS, not only to improve function but also to prevent diseases of inactivity. The present study suggests that reducing sedentary time, increasing time spent in light intensity activity, and increasing time spent in higher intensities of light activity may be appropriate as initial goals for exercise interventions in people with symptomatic LSS and neurogenic claudication, transitioning to moderate activity when appropriate. Results of the present study also demonstrate the importance of employing disease-specific measures for assessment of performance in LSS, and highlight the potential value of these methods for developing targeted and realistic goals for physical activity. Physical activity goals could be personalized using objective assessment of performance with accelerometry. The present study is one step toward a personalized medicine approach for people with LSS, focusing on increasing physical function.

Year in review 2015: Interstitial lung disease, pulmonary vascular disease, pulmonary function, sleep and ventilation, cystic fibrosis and paediatric lung disease.

Keywords: interstitial lung disease; lung function; paediatric lung disease; pulmonary vascular disease; sleep

Measuring Physical Activity and Sedentary Behavior in Youth with Type 2 Diabetes.

Lifestyle interventions that encourage increasing physical activity (PA) and losing weight are critical for overweight and obese youth with comorbid conditions. Assessing PA within such lifestyle intervention efforts requires measurement tool(s) that are both accurate and appropriate for these youth. This research compares PA levels and sedentary behavior in an ethnically diverse cohort of overweight/obese youth with type 2 diabetes using both accelerometry and a questionnaire previously validated in the general youth population. Spearman's correlations were used to compare time spent sedentary and in different PA intensities between a questionnaire, the three-day PA recall (3DPAR), and an objective PA measure, the ActiGraph accelerometer, in 236 overweight/obese youth with diabetes. Spearman correlations between 3DPAR and accelerometer results for total PA were small and not significant (rho = 0.11, p > 0.05 for males and females). Correlations for specific PA intensities (moderate/vigorous and light) were also small and not significant. Sedentary time between instruments was significant, but weakly correlated in females (rho = 0.19, p < 0.05), but not in males (rho = 0.07, p = 0.48). Subjective PA measures validated in the general youth population may not be the best method for differentiating levels of movement in overweight/obese youth with type 2 diabetes, who spend most of their time in light-intensity activity and sedentary pursuits with little or no time spent in moderate/vigorous-intensity activities. Objective measures such as accelerometers that can capture the lower end of the movement scale are likely the more appropriate measures under these conditions.

Effects of Standing and Light-Intensity Activity on Ambulatory Blood Pressure.

This study aimed to compare ambulatory blood pressure (ABP) response to accumulated standing (STAND), cycling (CYCLE), and walking (WALK) to a sitting-only (SIT) day in adults. Nine overweight or obese (body mass index, 28.7 ± 2.7 kg · m(-2)) adults (30 ± 15 yr) participated in this randomized crossover full-factorial study. Four conditions (WALK, STAND, CYCLE, and SIT) were randomly performed 1 wk apart. WALK, STAND, and CYCLE conditions consisted of progressively increasing activity time to accumulate 2.5 h during an 8-h simulated workday. WALK (1.0 mph) and STAND (0.0 mph) were completed on a treadmill placed underneath a standing-height desk. During CYCLE, participants pedaled on a Monark cycle ergometer at a cadence and energy expenditure equivalent to WALK. Participants remained seated during the SIT condition. Participants wore an ABP cuff from 0800 h until 2200 h on all conditions. Linear mixed models were used to test condition differences in systolic (SBP) and diastolic (DBP) blood pressure. Chi-square was used to detect frequency difference of BP load. There was a whole-day (during and after work hours) SBP and DBP treatment effect (P < 0.01). Systolic blood pressure during STAND (132 ± 17 mm Hg), WALK (133 ± 17 mm Hg), and CYCLE (130 ± 16 mm Hg) were lower compared with that during SIT (137 ± 17 mm Hg) (all P < 0.01). CYCLE was lower than STAND (P = 0.04) and WALK (P < 0.01). For DBP, only CYCLE (69 ± 12 mm Hg) was lower than SIT (71 ± 13 mm Hg; P < 0.01). Compared with SIT, WALK, STAND, and CYCLE reduced SBP load by 4%, 4%, and 13%, respectively (all P < 0.01). Compared with sitting, accumulating 2.5 h of light-intensity physical activity or standing during an 8-h workday may reduce ABP during and after work hours.

Dose–response association of physical activity with HbA1c: Intensity and bout length

ObjectiveThe aims of this study were to characterize the dose–response relationship between moderate-to-vigorous intensity physical activity (MVPA), and light-intensity activity with HbA1c in adults at low, moderate, and high risks of type 2 diabetes, and to compare the relationship of short (1 to 9min) versus long (10+min) bouts of MVPA with HbA1c. MethodsData from 2707 participants from the 2003–2006 National Health And Nutrition Examination Survey were analyzed in 2014–2015. Type 2 diabetes risk was classified into three groups based upon age (<40years; ≥40years) and BMI (<30; ≥30). The relationship between HbA1c and accelerometer-based physical activity variables was assessed using multiple regression models. ResultsThere was a curvilinear dose–response relationship between HbA1c with total activity and MVPA in adults at moderate or high risk for type 2 diabetes: higher amounts of physical activity were associated with lower HbA1c. The association of physical activity on HbA1c was stronger at lower levels of physical activity. There was no dose–response relationship in adults at low risk for type 2 diabetes. The relationship between short bouts with HbA1c was stronger than for bouts≥10min. ConclusionsIn adults at risk for type 2 diabetes, there is a dose–response relationship between physical activity and HbA1c levels such that the relationship: (1) is curvilinear; (2) is stronger when a higher percent of total activity comes from MVPA; and (3) is more potent with short bouts of MVPA. Fractionalized physical activity of at least moderate-intensity may contribute to long-term glucose control.