Compliance with physical activity guidelines in a group of UK-based postal workers using an objective monitoring technique

Comparing cadence-based and machine learning based estimates for physical activity intensity classification: The UK Biobank

OBJECTIVES

Cadence thresholds have been widely used to categorize physical activity intensity in health-related research. We examined the convergent validity of two cadence-based intensity classification approaches against a machine-learning-based intensity schema in 84,315 participants (≥40 years) with wrist-worn accelerometers.

DESIGN

Validity study.

METHODS

Both cadence-based methods (one-level cadence, two-level cadence) calculated intensity-specific time based on cadence-thresholds while the two-level cadence identified stepping behaviors first. We used an overlapping plot, mean absolute error, and Spearman's correlation coefficient to examine agreements between the cadence-based and machine-learning methods. We also evaluated agreements between methods based on practically-important-difference (moderate-to-vigorous-physical activity: ±20 min/day, moderate-physical activity: ±15, vigorous-physical activity: ±2.5, light-physical activity: ±30).

RESULTS

The group-level (median) minutes of moderate-to-vigorous- and moderate-physical activity estimated by one-level cadence were within the range of practically-important-difference compared to the machine-learning method (bias of median: moderate-to-vigorous-physical activity, -3.5, interquartile range [-15.8, 12.2]; moderate-physical activity, -6.0 [-17.2, 4.1]). The group-level vigorous- and light-physical activity minutes derived by two-level cadence were within practically-important-difference range (vigorous-physical activity: -0.9 [-3.1, 0.5]; light-physical activity, -1.3 [-28.2, 28.9]). The individual-level differences between the cadence-based and machine learning methods were high across intensities (e.g., moderate-to-vigorous-physical activity: mean absolute error [one-level cadence: 24.2 min/day; two-level cadence: 26.2]), with the proportion of participants within the practically-important-difference ranging from 8.4 % to 61.6 %.

CONCLUSIONS

One-level cadence showed acceptable group-level estimates of moderate-to-vigorous and moderate-physical activity while two-level cadence showed acceptable group-level estimates of vigorous- and light-physical activity. The cadence-based methods might not be appropriate for individual-level intensity-specific time estimation.

The feasibility and acceptability of an app-based intervention with brief behavioural support (APPROACH) to promote brisk walking in people diagnosed with breast, prostate and colorectal cancer in the UK

INTRODUCTION

Increased moderate to vigorous physical activity (MVPA) can improve clinical and psychosocial outcomes for people living with and beyond cancer (LWBC). This study aimed to assess the feasibility and acceptability of trial procedures in a pilot randomised controlled trial (RCT) of a theory-driven app-based intervention with behavioural support focused on promoting brisk walking (a form of MVPA) in people LWBC (APPROACH).

METHODS

Participants diagnosed with breast, prostate or colorectal cancer were recruited from a single UK hospital site. Assessments at baseline and 3 months included online questionnaires, device-measured brisk walking (activPAL accelerometer) and self-reported weight and height. Participants were randomised to intervention or control (care as usual). The intervention comprised a non-cancer-specific app to promote brisk walking (National Health Service 'Active 10') augmented with print information about habit formation, a walking planner and two behavioural support telephone calls. Feasibility and acceptability of trial procedures were explored. Initial estimates for physical activity informed a power calculation for a phase III RCT. A preliminary health economics analysis was conducted.

RESULTS

Of those medically eligible, 369/577 (64%) were willing to answer further eligibility questions and 90/148 (61%) of those eligible were enrolled. Feasibility outcomes, including retention (97%), assessment completion rates (>86%) and app download rates in the intervention group (96%), suggest that the trial procedures are acceptable and that the intervention is feasible. The phase III RCT will require 472 participants to be randomised. As expected, the preliminary health economic analyses indicate a high level of uncertainty around the cost-effectiveness of the intervention.

CONCLUSIONS

This pilot study demonstrates that a large trial of the brisk walking intervention with behavioural support is both feasible and acceptable to people LWBC. The results support progression onto a confirmatory phase III trial to determine the efficacy and cost-effectiveness of the intervention.

Turning Back the Clock: A Retrospective Single-Blind Study on Brain Age Change in Response to Nutraceuticals Supplementation vs. Lifestyle Modifications

BACKGROUND

There is a growing consensus that chronological age (CA) is not an accurate indicator of the aging process and that biological age (BA) instead is a better measure of an individual's risk of age-related outcomes and a more accurate predictor of mortality than actual CA. In this context, BA measures the "true" age, which is an integrated result of an individual's level of damage accumulation across all levels of biological organization, along with preserved resources. The BA is plastic and depends upon epigenetics. Brain state is an important factor contributing to health- and lifespan.

METHODS AND OBJECTIVE

Quantitative electroencephalography (qEEG)-derived brain BA (BBA) is a suitable and promising measure of brain aging. In the present study, we aimed to show that BBA can be decelerated or even reversed in humans (N = 89) by using customized programs of nutraceutical compounds or lifestyle changes (mean duration = 13 months).

RESULTS

We observed that BBA was younger than CA in both groups at the end of the intervention. Furthermore, the BBA of the participants in the nutraceuticals group was 2.83 years younger at the endpoint of the intervention compared with their BBA score at the beginning of the intervention, while the BBA of the participants in the lifestyle group was only 0.02 years younger at the end of the intervention. These results were accompanied by improvements in mental-physical health comorbidities in both groups. The pre-intervention BBA score and the sex of the participants were considered confounding factors and analyzed separately.

CONCLUSIONS

Overall, the obtained results support the feasibility of the goal of this study and also provide the first robust evidence that halting and reversal of brain aging are possible in humans within a reasonable (practical) timeframe of approximately one year.

Defining Continuous Walking Events in Free-Living Environments: Mind the Gap

In free-living environments, continuous walking can be challenging to achieve without encountering interruptions, making it difficult to define a continuous walking event. While limited research has been conducted to define a continuous walking event that accounts for interruptions, no method has considered the intensity change caused by these interruptions, which is crucial for achieving the associated health outcomes. A sample of 24 staff members at the University of Salford were recruited. The participants wore an accelerometer-based device (activPAL™) for seven days continuously and completed an activity diary, to explore a novel methodological approach of combining short interruptions of time between walking events based on an average walking cadence. The definition of moderate-to-vigorous physical activity (MVPA) used was a minimum walking cadence of either 76, 100, or 109 steps/min. The average daily time spent in MVPA increased from 75.2 ± 32.6 min to 86.5 ± 37.4 min using the 76 steps/min, 48.3 ± 29.5 min to 53.0 ± 33.3 min using the 100 steps/min threshold, and 31.4 ± 20.5 min to 33.9 ± 22.6 min using the 109 steps/min threshold; the difference before grouping and after grouping was statistically significant (p < 0.001). This novel method will enable future analyses of the associations between continuous walking and health-related outcomes.

Cross-sectional associations of device-measured sedentary behaviour and physical activity with cardio-metabolic health in the 1970 British Cohort Study

AIMS

This study aimed to examine the cross-sectional associations of thigh accelerometry-assessed sedentary behaviour and moderate-to-vigorous physical activity (MVPA) with cardio-metabolic health markers and prevalent diabetes in a population sample of middle-aged British adults.

METHODS

Participants (n = 4892) from the age-46-to-48 wave of the 1970 British Cohort Study were fitted with a waterproofed activPAL3 micro device. Total/prolonged sedentary time, breaks and MVPA were the main exposures. We dichotomized prolonged sedentary time and MVPA based on the corresponding median, generating four combinations as categorical exposures. Outcomes comprised of diabetes and seven cardio-metabolic health markers. We used logistic regression and generalized linear models to examine independent/joint associations, conducting a minimally adjusted model including demographics and contextual covariates, and further adjusted for total sedentary time and/or MVPA as applicable.

RESULTS

Each set of 10 sedentary breaks and 1 h of prolonged sedentary time were associated with HbA_1c (mmol/mol) [B = -0.18 (-0.33, -0.03) and 2.35 (1.01, 3.69), respectively]. Each set of 10 sedentary breaks and 1 h of MVPA were favourably associated with diabetes [adjusted odds ratio (AOR): 0.80 (0.71, 0.99) and 0.42 (0.26, 0.67), respectively]. Joint analyses showed that only the low MVPA × long sedentary time combination had significantly higher odds for diabetes than the referent high MVPA × short sedentary time combination [AOR: 1.89 (1.17, 3.03)].

CONCLUSIONS

Each set of additional 10 sedentary breaks per day was associated with 20% lower odds for diabetes. A low physical activity level combined with long sedentary time might synergistically deteriorate cardio-metabolic health.

Measuring Daily Compliance With Physical Activity Tracking in Ambulatory Surgery Patients: Comparative Analysis of Five Compliance Criteria

BACKGROUND

Physical activity trackers such as the Fitbit can allow clinicians to monitor the recovery of their patients following surgery. An important issue when analyzing activity tracker data is to determine patients' daily compliance with wearing their assigned device, using an appropriate criterion to determine a valid day of wear. However, it is currently unclear as to how different criteria can affect the reported compliance of patients recovering from ambulatory surgery. Investigating this issue can help to inform the use of activity data by revealing factors that may impact compliance calculations.

OBJECTIVE

This study aimed to understand how using different criteria can affect the reported compliance with activity tracking in ambulatory surgery patients. It also aimed to investigate factors that explain variation between the outcomes of different compliance criteria.

METHODS

A total of 62 patients who were scheduled to undergo total knee arthroplasty (TKA, ie, knee replacement) volunteered to wear a commercial Fitbit Zip activity tracker over an 8-week perioperative period. Patients were asked to wear the Fitbit Zip daily, beginning 2 weeks prior to their surgery and ending 6 weeks after surgery. Of the 62 patients who enrolled in the study, 20 provided Fitbit data and underwent successful surgery. The Fitbit data were analyzed using 5 different daily compliance criteria, which consider patients as compliant with daily tracking if they either register >0 steps in a day, register >500 steps in a day, register at least one step in 10 different hours of the day, register >0 steps in 3 distinct time windows, or register >0 steps in 3 out of 4 six-hour time windows. The criteria were compared in terms of compliance outcomes produced for each patient. Data were explored using heatmaps and line graphs. Linear mixed models were used to identify factors that lead to variation between compliance outcomes across the sample.

RESULTS

The 5 compliance criteria produce different outcomes when applied to the patients' data, with an average 24% difference in reported compliance between the most lenient and strictest criteria. However, the extent to which each patient's reported compliance was impacted by different criteria was not uniform. Some individuals were relatively unaffected, whereas others varied by up to 72%. Wearing the activity tracker as a clip-on device, rather than on the wrist, was associated with greater differences between compliance outcomes at the individual level (P=.004, r=.616). This effect was statistically significant (P<.001) in the first 2 weeks after surgery. There was also a small but significant main effect of age on compliance in the first 2 weeks after surgery (P=.040). Gender and BMI were not associated with differences in individual compliance outcomes. Finally, the analysis revealed that surgery has an impact on patients' compliance, with noticeable reductions in activity following surgery. These reductions affect compliance calculations by discarding greater amounts of data under strict criteria.

CONCLUSIONS

This study suggests that different compliance criteria cannot be used interchangeably to analyze activity data provided by TKA patients. Surgery leads to a temporary reduction in patients' mobility, which affects their reported compliance when strict thresholds are used. Reductions in mobility suggest that the use of lenient compliance criteria, such as >0 steps or windowed approaches, can avoid unnecessary data exclusion over the perioperative period. Encouraging patients to wear the device at their wrist may improve data quality by increasing the likelihood of patients wearing their tracker and ensuring that activity is registered in the 2 weeks after surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03518866; https://clinicaltrials.gov/ct2/show/NCT03518866.

Questionnaire-Based Prevalence of Physical Activity Level on Adults According to Different International Guidelines: Impact on Surveillance and Policies

BACKGROUND

The World Health Organization recommends 150 minutes of moderate to vigorous physical activity (PA) throughout the week. However, the weekly frequency of PA and how to combine moderate and vigorous PA to define who reaches the recommended PA are controversial. PA level might be highly different based on the recommendation and/or the criteria employed.

METHODS

Demographic data and PA level evaluated by International Physical Activity Questionnaire from 3 random and representative samples from 1 state, 1 city, and 1 local organization in Brazil were analyzed (n = 2961). Nine criteria from different recommendations were used to define PA level. Prevalence estimates and 95% confidence intervals of sufficient PA were calculated for each criterion and compared with the referent (World Health Organization guideline). Total agreement, sensitivity, and specificity were also calculated with 95% confidence interval.

RESULTS

When a weekly frequency of PA was required, the prevalence of sufficient PA decreased by 11% (P < .05). For all criteria, doubling the vigorous PA minutes was similar to simply adding them to moderate PA. These findings are consistent regardless of sex, age, and educational level.

CONCLUSION

Prevalence estimates and agreement between different PA recommendations were significantly affected when a minimum frequency was required but did not change when vigorous PA minutes were doubled.

Device-measured physical activity, sedentary behaviour and cardiometabolic health and fitness across occupational groups: a systematic review and meta-analysis

BACKGROUND

With approximately 8 hours of one's waking day spent at work, occupational tasks and environments are important influencers on an individual's physical activity (PA) and sedentary behaviours. Little research has compared device-measured physical activity, sedentary behaviour and cardiometabolic outcomes between occupational groups.

OBJECTIVE

To compare device-measured movement (sedentary time [ST], light intensity physical activity [LPA], moderate-to-vigorous intensity physical activity [MVPA], and steps) across occupations. The secondary objective was to examine whether cardiometabolic and fitness outcomes differed by occupation.

METHODS

Five bibliographic databases were searched to identify all studies which included working age, employed adults from high-income countries, and reported on device-measured movement within occupations. Risk of bias within and across studies was assessed. Results were synthesized using meta-analyses and narrative syntheses.

RESULTS

The review includes 132 unique studies with data from 15,619 participants. Working adults spent ~ 60% of their working and waking time engaged in sedentary behaviour; a very small proportion (~ 4%) of the day included MVPA. On average, workers accumulated 8124 steps/day. Office and call center workers' steps/day were among the lowest, while those of postal delivery workers were highest. Office workers had the greatest ST and the lowest time in LPA both at work and during wakeful time. However, office workers had the greatest minutes sent in MVPA during wakeful hours. Laborers had the lowest ST and spent a significantly greater proportion of their work time in LPA and MVPA. Healthcare and protective services workers had higher levels of LPA at work compared to other occupations. Workers in driving-based occupations tended to have a higher body mass index and blood pressure.

CONCLUSION

This review identifies that occupational and wakeful time PA and ST differed between occupations. Future studies are needed to assess whether patterns differ by age and sex, describe leisure-time movement and movement patterns, and the relationship with cardiometabolic health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017070448 .

Effects of two behavioral cardiac rehabilitation interventions on physical activity: A randomized controlled trial

BACKGROUND

Standard cardiac rehabilitation (CR) is insufficient to help patients achieve an active lifestyle. The effects of two advanced and extended behavioral CR interventions on physical activity (PA) and sedentary behavior (SB) were assessed.

METHODS

In total, 731 patients with ACS were randomized to 1) 3months of standard CR (CR-only); 2) 3months of standard CR with three pedometer-based, face-to-face PA group counseling sessions followed by 9months of aftercare with three general lifestyle, face-to-face group counseling sessions (CR+F); or 3) 3months of standard CR, followed by 9months of aftercare with five to six general lifestyle, telephonic counseling sessions (CR+T). An accelerometer recorded PA and SB at randomization, 3months, 12months, and 18months.

RESULTS

The CR+F group did not improve their moderate-to-vigorous intensity PA (MVPA) or SB time compared to CR-only (between-group difference=0.24% MVPA, P=0.349; and 0.39% SB, P=0.529). However, step count (between-group difference=513 steps/day, P=0.021) and time in prolonged MVPA (OR=2.14, P=0.054) improved at 3months as compared to CR-only. The improvement in prolonged MVPA was maintained at 18months (OR=1.91, P=0.033). The CR+T group did not improve PA or SB compared to CR-only.

CONCLUSIONS

Adding three pedometer-based, face-to-face group PA counseling sessions to standard CR increased daily step count and time in prolonged MVPA. The latter persisted at 18months. A telephonic after-care program did not improve PA or SB. Although after-care should be optimized to improve long-term adherence, face-to-face group counseling with objective PA feedback should be added to standard CR.

Associations between physical behaviour patterns and levels of depressive symptoms, anxiety and well-being in middle-aged adults: a cross-sectional study using isotemporal substitution models

OBJECTIVE

To examine the compositional effects of physical behaviour on mental health.

DESIGN

Cross-sectional study.

SETTING

A population-representative random sample (Mitchelstown cohort) was recruited from a large primary care centre in Mitchelstown, County Cork, Ireland.

PARTICIPANTS

In total 3807 potential participants were selected from the practice list. Following exclusion of duplicates, deaths and ineligibles, 3043 were invited to participate and of these, 2047 (49.2% men) completed the questionnaire and physical examination components of the baseline assessment during the study period (April 2010 and May 2011). Accelerometers were introduced into the study in January 2011. Of the 745 participants seen between January and May of 2011, 475 (44.6% men) subjects (response rate 64%) agreed to participate and of these 397 (46.1% men) had valid accelerometer data.

PRIMARY AND SECONDARY OUTCOME MEASURES

Participants wore the wrist GENEActiv accelerometer for 7 consecutive days. Data were summarised into 60 s epochs and activity categorised as sedentary behaviour, light or moderate-to-vigorous physical activity (MVPA). Levels of depressive and anxiety symptoms were assessed using the Centre for Epidemiologic Studies Depression scale and the Hospital Anxiety and Depression Scale. Well-being was assessed using the WHO-5 well-being scale.

RESULTS

In adjusted isotemporal models, a 30 min increase in light activity per day was associated with a significant decrease in levels of anxiety symptoms (B=-0.34; 95% CI -0.64 to -0.04) and a significant increase in levels of well-being (B=0.58; 95% CI 0.05 to 1.11). No statistically significant associations were observed between any physical behaviour and depressive symptoms or when sedentary behaviour was substituted with MVPA (P>0.05).

CONCLUSION

Although based on a cross-sectional study, the findings suggest that substituting light activity for sedentary behaviour may have positive associations with symptoms of anxiety and reported well-being among middle-aged adults.

Patterns of objectively assessed physical activity and sedentary time: Are Nigerian health professional students complying with public health guidelines?

BACKGROUND

Understanding patterns of physical activity and sedentary time is important to effective population-wide primary prevention and control of non-communicable diseases. This study examined the patterns of objectively assessed physical activity and sedentary time, and the prevalence of compliance with physical activity guidelines according to different public health recommendations in a sub-population of health professional students in Nigeria.

METHODS

A cross-sectional study was conducted among 102 health professional students (age = 19-34 years old, 43.1% women) of the University of Maiduguri, Nigeria. Participants wore Actigraph accelerometers on their waist for minimum of 5 days/week to objectively measure intensity and duration of physical activity and sedentary time. Prevalence and demographic patterns of physical activity and sedentary time were examined using descriptive and inferential statistics.

RESULTS

The students spent most time in sedentary activity (458.6 ± minutes/day, about 61% of daily time) and the least in vigorous-intensity activity (2.1 ± 4.4 minutes/day, about 0.3% of daily time). Sedentary time was higher among older than younger students (P<0.038) and among medical laboratory science students than physiotherapy and nursing students (P = 0.046). Total physical activity was higher among nursing and medical students than medical laboratory science students (P = 0.041). Although, 85.3% of the students engaged in 150 minutes/week of moderate-to-vigorous physical activity, only 2.9% met the guideline of 75 minutes/week of vigorous intensity activity.

CONCLUSIONS

Prevalence of sedentary time was high while that of vigorous-intensity activity was very low among health professional students in Nigeria. Compliance with physical activity guidelines was mainly through accumulation of moderate intensity activity. The results suggest that age and academic programme may influence physical activity level and sedentary behaviour of health professional students in Nigeria. These findings provide preliminary evidence that could be used to inform the needs to develop interventions to improve and support active lifestyle behaviour among students in Nigerian universities.

Accelerometer-measured sedentary time and physical activity-A 15 year follow-up of mortality in a Swedish population-based cohort

OBJECTIVES

To investigate the associations of objectively assessed sedentary time, light intensity physical activity (PA), moderate to vigorous intensity PA (MVPA), and total PA with all-cause mortality and mortality from cardiovascular disease (CVD) or cancer in a Swedish population-based cohort with 15 years follow-up time.

DESIGN

Longitudinal prospective cohort study.

METHODS

Data from 851 persons (56% women) ≥35 years at baseline were included. Primary exposure variables were time (min/day) spent sedentary, in light intensity PA and in MVPA, and total counts from an Actigraph 7164 accelerometer. Data on all-cause mortality and mortality from CVD or cancer were obtained from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of mortality with 95% confidence intervals (CI).

RESULTS

Compared with the least sedentary participants, those in the most sedentary tertile had an increased risk of all-cause mortality, HR: 2.7 (1.4, 5.3), CVD mortality, HR: 5.5 (1.4, 21.2) and cancer mortality, HR: 4.3 (1.2, 16.0). For all-cause mortality, those in the highest light intensity PA tertile had a HR 0.34 (0.17, 0.67) compared with the lowest tertile. A similar pattern was found for CVD and cancer mortality. More time spent in MVPA was associated with the largest risk reduction for CVD mortality, with an almost 90% lower risk in the tertile with the most time in MVPA.

CONCLUSIONS

This study confirms a strong inverse relationship between MVPA and mortality, and adds new insight for the understanding of the associations between sedentary time and light intensity PA and mortality.

Attending a workplace: its contribution to volume and intensity of physical activity

Understanding the contribution that attending a workplace has in accumulating physical activity (PA) may help inform strategies used to increase PA. This study explores the influence that attending work has on the total number of steps taken and the time spent in moderate to vigorous activity (MVPA). A global position system (GPS) was used to identify the geographical domain of the participant. An activity monitor (activPAL, PALtechnologies Ltd, Glasgow, UK) was employed to measure the number of steps taken and the cadence of those steps. Both devices were worn for seven consectutive days and 5 work days extracted post data collection. The data from the two devices were synchronised allowing domain, volume and intensity of PA to be explored. The distance from the home domain to the workplace was used to establish if there was any relationship between commute distance and number of steps accumulated and time in MVPA. Twenty-six office workers (17F; mean age 38 (range 23-65)) were recruited. The number of steps taken per day on average for the group was 11 008 (SD  ±  2999) with time spent in MVPA per day being 32.7 (SD  ±  17.1) min. The commute accounted for 32% or 3550 (SD  ±1664) of the steps taken and 68% or 22.0 (SD  ±14.1) min of MVPA. No statistically significant correlations with distance from home to the workplace for either variable were found. This work explores the contribution that attending work makes to PA, combining data from a GPS system and an objective activity monitor. The commute to works accounts for more than two-thirds of the MVPA accumulated per day. This provides meaningful in sight into the volume and intensity of individuals' activity and also its context.

The Effect of Active versus Passive Recovery Periods during High Intensity Intermittent Exercise on Local Tissue Oxygenation in 18 - 30 Year Old Sedentary Men

PURPOSE

High intensity interval training (HIIT) has been proposed as a time-efficient format of exercise to reduce the chronic disease burden associated with sedentary behaviour. Changes in oxygen utilisation at the local tissue level during an acute session of HIIT could be the primary stimulus for the health benefits associated with this format of exercise. The recovery periods of HIIT effect the physiological responses that occur during the session. It was hypothesised that in sedentary individuals, local and systemic oxygen utilisation would be higher during HIIT interspersed with active recovery periods, when compared to passive recovery periods.

METHODS

Twelve sedentary males (mean ± SD; age 23 ± 3 yr) completed three conditions on a cycle ergometer: 1) HIIT with passive recovery periods between four bouts (HIITPASS) 2) HIIT with active recovery periods between four bouts (HIITACT) 3) HIITACT with four HIIT bouts replaced with passive periods (REC). Deoxygenated haemoglobin (HHb) in the vastus lateralis (VL) and gastrocnemius (GN) muscles and the pre-frontal cortex (FH), oxygen consumption (VO2), power output and heart rate (HR) were measured continuously during the three conditions.

RESULTS

There was a significant increase in HHb at VL during bouts 2 (p = 0.017), 3 (p = 0.035) and 4 (p = 0.035) in HIITACT, compared to HIITPASS. Mean power output was significantly lower in HIITACT, compared to HIITPASS (p < 0.001). There was a significant main effect for site in both HIITPASS (p = 0.029) and HIITACT (p = 0.005). There were no significant differences in VO2 and HR between HIITPASS and HIITACT.

CONCLUSIONS

The increase in HHb at VL and the lower mean power output during HIITACT could indicate that a higher level of deoxygenation contributes to decreased mechanical power in sedentary participants. The significant differences in HHb between sites indicates the specificity of oxygen utilisation.

Levels and Patterns of Objectively Assessed Physical Activity and Compliance with Different Public Health Guidelines in University Students

BACKGROUND

Physical activity (PA) is associated with health enhancement. The aim of this study was to assess: 1) levels and patterns of PA in university students by using accelerometers; and 2) the percentage of fulfilment of PA recommendations for adults, according to different public health guidelines.

METHODS

Observational cross-sectional study (Cuenca's Adults Study) involving 296 (206 women) healthy Spanish university students aged 18-25 years old. Participants wore the ActiGraph GT1M accelerometer for seven consecutive days. Total PA, steps and time spent in sedentary time, light, moderate, vigorous, and moderate to vigorous PA (MVPA) was assessed, and the prevalence of sufficient PA was calculated according to various public health guidelines.

RESULTS

No sex differences in total PA were found. University students were more sedentary during weekend days than weekdays (p<0.05). Only 30.3% of participants accumulated 30 min/day at least five days a week of MVPA. A total of 5.4% of students met the recommendation of 150 min/week of MVPA or 75 min/week of vigorous PA, in PA bouts of at least 10 min. using the same definition, but on five or more days a week, only 0.5% students were found to meet the recommendation. In addition, only 0.5% of students met the recommendation of 30 min/day of MVPA, at least five days a week and in bouts of at least 10 min. Finally, 28.1% of the students met the recommendation of 10,000 steps/day.

CONCLUSIONS

Our study shows a high incidence of sedentary time in university students. The number of students meeting PA recommendations significantly differed depending on the recommendation proposed. Specific strategies to promote PA in this population are necessary as well as an agreement as to which PA guidelines should be used.

Differences between work and leisure in temporal patterns of objectively measured physical activity among blue-collar workers

Background

Leisure time physical activity (LTPA) is generally associated with favorable cardiovascular health outcomes, while occupational physical activity (OPA) shows less clear, or even opposite, cardiovascular effects. This apparent paradox is not sufficiently understood, but differences in temporal patterns of OPA and LTPA have been suggested as one explanation. Our aim was to investigate the extent to which work and leisure (non-occupational time) differ in temporal activity patterns among blue-collar workers, and to assess the modification of these patterns by age and gender.

Methods

This study was conducted on a cross-sectional sample of male (n = 108) and female (n = 83) blue-collar workers, aged between 21 and 65 years. Physical activity and sedentary behavior were assessed using accelerometers (Actigraph GT3X+) worn on the thigh and trunk for four consecutive days. Temporal patterns of OPA and LTPA were retrieved using Exposure Variation Analysis (EVA), and expressed in terms of percentage of work and leisure time spent in uninterrupted periods of different durations (<1 min, 1–5 min, 5–10 min, 10–30 min, 30–60 min and > 60 min) of sitting, standing, and walking. Repeated measures ANOVA and linear regression analyses were used to test a) possible differences between OPA and LTPA in selected EVA derivatives, and b) the modification of these differences by age and gender.

Results

OPA showed a larger percentage time walking in brief (<5 min) periods [mean (SD): 33.4 % (12.2)], and less time in prolonged (>30 min) sitting [7.0 % (9.3)] than LTPA [walking 15.4 % (5.0); sitting 31.9 % (15.3)], even after adjustment for the difference between work and leisure in total time spent in each activity type. These marked differences in the temporal pattern of OPA and LTPA were modified by gender, but not age.

Conclusion

We found that the temporal patterns of OPA and LTPA among blue-collar workers were markedly different even after adjustment for total physical activity time, and that this difference was modified by gender. We recommend using EVA derivatives in future studies striving to disentangle the apparent paradoxical cardiovascular effect of physical activity at work and during leisure.

Quantifying the cadence of free-living walking using event-based analysis

PURPOSE

Free-living walking occurs over a wide range of durations and intensities (cadence). Therefore, its characterisation requires a full description of the distribution of duration and cadence of these walking events. The aim was to use event-based analysis to characterise this in a population with intermittent claudication (IC) and a healthy matched control group.

METHODS

Seven-day walking activity was recorded using the activPAL activity monitor in a group of people with IC (n=30) and an age-matched control group (n=30). The cadence, number of steps and duration of individual walking events were calculated and outcomes were derived, and compared (p<0.05), based on thresholds applied.

RESULTS

Both groups had similar number of walking events per day (392±117 vs 415±160). The control group accumulated a greater proportion of their walking at higher cadences and 32% of their steps were taken at a cadence above 100 steps/min, for the IC group this was 20%. Longer walking events had higher cadences and the IC group had fewer of these. As walking events became longer the cadence increased but the inter-event cadence variability decreased. More purposeful walking might occur at a higher cadence, and be performed at a preferred cadence. Individuals with IC had a smaller volume of walking, but these differences occurred almost entirely above a cadence of 90 steps/min.

CONCLUSIONS

This is the first study which has quantified the cadence of continuous periods of free-living walking. The characteristics (duration, number of steps and cadence) of all the individual walking events were used to derive novel outcomes, providing new insights into free-living walking behaviour.

Positive messaging promotes walking in older adults

Walking is among the most cost-effective and accessible means of exercise. Mounting evidence suggests that walking may help to maintain physical and cognitive independence in old age by preventing a variety of health problems. However, older Americans fall far short of meeting the daily recommendations for walking. In 2 studies, we examined whether considering older adults' preferential attention to positive information may effectively enhance interventions aimed at promoting walking. In Study 1, we compared the effectiveness of positive, negative, and neutral messages to encourage walking (as measured with pedometers). Older adults who were informed about the benefits of walking walked more than those who were informed about the negative consequences of failing to walk, whereas younger adults were unaffected by framing valence. In Study 2, we examined within-person change in walking in older adults in response to positively- or negatively-framed messages over a 28-day period. Once again, positively-framed messages more effectively promoted walking than negatively-framed messages, and the effect was sustained across the intervention period. Together, these studies suggest that consideration of age-related changes in preferences for positive and negative information may inform the design of effective interventions to promote healthy lifestyles. Future research is needed to examine the mechanisms underlying the greater effectiveness of positively- as opposed to negatively-framed messages and the generalizability of findings to other intervention targets and other subpopulations of older adults.

Evolution of accelerometer methods for physical activity research

The technology and application of current accelerometer-based devices in physical activity (PA) research allow the capture and storage or transmission of large volumes of raw acceleration signal data. These rich data not only provide opportunities to improve PA characterisation, but also bring logistical and analytic challenges. We discuss how researchers and developers from multiple disciplines are responding to the analytic challenges and how advances in data storage, transmission and big data computing will minimise logistical challenges. These new approaches also bring the need for several paradigm shifts for PA researchers, including a shift from count-based approaches and regression calibrations for PA energy expenditure (PAEE) estimation to activity characterisation and EE estimation based on features extracted from raw acceleration signals. Furthermore, a collaborative approach towards analytic methods is proposed to facilitate PA research, which requires a shift away from multiple independent calibration studies. Finally, we make the case for a distinction between PA represented by accelerometer-based devices and PA assessed by self-report.

Duration and patterns of habitual physical activity in adolescents and young adults with cerebral palsy

AIM

Adolescents and young adults with cerebral palsy (CP) show reduced motor function and gait efficiency, and lower levels of habitual physical activity (HPA), than adolescents with typical development and children with CP. This study examined activity duration and patterns in this population in the Middle East through long-term monitoring of a large sample using accelerometers.

METHOD

Adolescents and young adults with bilateral CP at Gross Motor Function Classification System (GMFCS) levels II, III, and IV, were monitored in their habitual environment for four consecutive days with ActivPAL3 monitors. Time spent in sedentary, standing, and walking activities, and frequency of walking steps and transitions, were analysed for each GMFCS level.

RESULTS

Measurements were made on 222 participants (132 males, 90 females; mean age 16 y 9 mo SD 2y, range 13 y 4 mo-22 y). The Mann-Whitney U test demonstrated significant differences (p<0.05) between GMFCS levels, showing reduced walking and standing activity and increased sedentary duration at higher GMFCS levels (p<0.001), except for increased standing time between GMFCS levels II and III (p=0.07). Participants in educational facilities exhibited less sedentary behaviour than those who were homebound (p<0.05).

INTERPRETATION

These descriptions of duration and frequency of active and sedentary behaviours may serve as a basis for recommendations to minimize inactivity in this population. Adolescents and young adults with CP in the Middle East demonstrate similar patterns of HPA to their peers in other regions.

Step accumulation per minute epoch is not the same as cadence for free-living adults

PURPOSE

The term cadence has been used interchangeably to describe both the rate of stepping and the number of steps in a minute epoch. This is only strictly true if walking is continuous within that epoch. This study directly compared these two outcomes in minute epochs of data from free-living adults to assess the scale of any difference between them.

METHODS

A convenience sample of healthy adults wore an activPAL activity monitor for 7 d. The event record output of the activPAL, providing the start time and duration of each stride to the nearest 0.1 s, was used to calculate step accumulation (number of steps), duration of walking, and cadence (number of steps/duration of walking) for each minute of measurement.

RESULTS

Data from 117 individuals (78 females; mean age, 46 ± 16 yr; mean body mass index, 24.9 ± 3.7 kg·m-2) were analyzed. Twenty-one percent of minutes (n = 310d-1) contained walking. The distribution (most minutes fewer than 40 steps per minute) and mean (34 ± 9 steps per minute) of step accumulation were very different from that of cadence (most minutes between 60 and 100 steps per minute; mean, 76 ± 6 steps per minute). Only 12% of minutes with stepping were walked continuously, whereas 69% of minutes with stepping contained less than 30 s of walking. This is key to the difference between step accumulation and cadence, and means that cadence cannot be reconstructed from step accumulation without also knowing the duration that was walked.

CONCLUSION

Step accumulation, the number of steps in a fixed period, and cadence, the rate of stepping while walking, are not interchangeable outcome measures. It is vitally important that unambiguous terminology is used to describe the rate of stepping so that the outcomes of studies can be correctly interpreted.

Living well with disability: needs, values and competing factors

BACKGROUND

Obesity is more prevalent for disabled people (estimated as being between 27-62%) compared to the general population (17-22%). Disabled people are more likely to report poorer general health and acquire a range of obesity-related secondary conditions. Although there are many physical activity and nutrition initiatives aimed at obesity prevention, little is known about whether these options are relevant and accessible for disabled people. The Living Well Study aimed to better understand the issues faced by disabled people when engaging in physical activity and healthy eating.

METHODS

The study drew on a participatory action research design involving key stakeholders. There were two core cyclical phases (A and B), in which data collection was followed by a period of analysis, reflection and refinement. Focus groups and interviews were held with individuals who experience a range of disabilities, family members, service providers and representatives from disability advocacy groups. We sought to explore the importance and meaning of physical activity and healthy eating and factors that influenced engagement in these. Data in phase A were analysed using conventional content analysis drawing on constant comparative methods to identify themes of importance. In phase B, data analysis occurred alongside data collection, using a structured template to summarise participants' agreement or disagreement with the draft themes and recommendations, until the themes and recommendations were refined based on participants' corroboration.

RESULTS

146 participants aged between 10-69 years, from both rural and urban areas and of different cultural backgrounds participated. Seven interconnecting themes that related to engagement in living well behaviours emerged with a wide range of external factors (such as people, knowledge, time, cost, identity and the environment) impacting on living well options. The central theme - It depends: needs, values and competing factors - emphasised the complexity faced by a disabled person when balancing the external factors with their own personal values and needs in order to arrive at a decision to engage in healthy living behaviours.

CONCLUSIONS

Although disabled people experience similar issues when participating in healthy living behaviours as those living without disability, additional factors need to be addressed in order to improve opportunities for 'living well' in these populations. This information has implications for health professionals to target the relevance and content of interventions.

Compliance with different physical activity recommendations and its association with socio-demographic characteristics using an objective measure

Background

In the past decades, several public health guidelines concerning physical activity have been published. This study evaluated compliance with various physical activity guidelines and examined the associations between meeting the guidelines and socio-demographic characteristics.

Methods

Data were obtained from 357 Flemish men and women (41.9 ± 9.6 years). Physical activity was assessed for seven consecutive days using the SenseWear Armband. The prevalence of sufficient physical activity was calculated according to various public health guidelines. Logistic regressions examined the associations between socio-demographic characteristics and the odds of meeting the different guidelines.

Results

87.2% of men and 68.1% of women achieved ≥150 min/week of moderate-to-vigorous physical activity (MVPA), but only 57.6% and 37.3% accumulated this amount as ≥30 min/day on ≥5 days/week. With regard to vigorous physical activity, 27.9% of men and 15.7% of women achieved ≥75 min/week and 12.8% and 7.0% achieved ≥20 min/day on ≥3 days/week. In addition, 34.9% of men and 21.6% of women attained an average physical activity level (PAL) of 1.75 MET and thus met the criteria for weight maintenance. Only 16.3% of men and 14.1% of women took 10000 steps/day on 7 days/week. Women had a lower probability of achieving 30 min/day MVPA on 5 days/week (OR: 0.40), or a weekly total of 150 min or 500 MET.min MVPA or 75 min of vigorous activity compared to men (OR: 0.27-0.46). In addition, they were 50% less likely to meet the guidelines for weight maintenance. The odds of engaging in 150 min/week MVPA or attaining a PAL of 1.75 was lower with higher age. Educational level was positively related with accumulating 75 min/week of vigorous activity, but negatively with taking 10000 steps/day. Smokers were 60% less likely to participate weekly in 150 min of MVPA compared to non-smokers.

Conclusions

The prevalence of sufficient physical activity differed greatly depending on the definition used. Women and subjects older than 35 were less likely to meet the guidelines than men and younger subjects and thus are important groups to target in future interventions.

Take a walk in the park? A cross-over pilot trial comparing brisk walking in two different environments: park and urban

OBJECTIVE

The objective of the present study is to investigate whether differences exist between a 30 minute brisk walk taken in two different environments in order to determine which environment best facilitates current physical activity guidelines: park or urban.

METHODS

In this randomised cross-over pilot study, participants performed a self-timed 30 minute brisk walk in two different environments, park and urban, in Glasgow, Scotland (October 2009 to January 2010). Cadence, recorded using the activPAL™ activity monitor, was used to measure intensity. Outcome measures were: mean cadence; moderate-to-vigorous physical activity time accumulated in bouts lasting ≥ 10 min; number of walking breaks; and duration.

RESULTS

A convenience sample of 40 healthy adults was recruited: 16 males, 24 females, mean age 22.9 (5.5) years. The mean cadence for the whole walk was higher in the park: 119.3 (8.3) vs. 110.9 (8.9) steps/min. Participants accumulated more moderate-to-vigorous physical activity in ≥ 10 minute bouts during park walks: 25.5 (9.6) [median (interquartile range)] vs. 14.0 (20.3) min. There was no difference in self-timed duration between locations.

CONCLUSION

Participants accumulated more moderate-to-vigorous physical activity in bouts ≥ 10 min in duration on park walks due to the lack of interruptions in walking. Hence the park environment better facilitated the achievement of current physical activity guidelines. Further research involving a larger, more heterogeneous sample is recommended.

Event-based analysis of free-living behaviour

The quantification of free-living physical activities is important in understanding how physical activity and sedentary behaviour impact on health and also on how interventions might modify free-living behaviour to enhance health. Quantification, and the terminology used, has in many ways been determined by the choice of measurement technique. The inter-related issues around measurement devices and terminology used are explored. This paper proposes a terminology and a systematic approach for the analysis of free-living activity information using event-based activity data. The event-based approach uses a flexible hierarchical classification of events and, dependent on the research question, analysis can then be undertaken on a selection of these events. The quantification of free-living behaviour is therefore the result of the analysis on the patterns of these chosen events. The application of this approach is illustrated with results from a range of published studies by our group showing how event-based analysis provides a flexible yet robust method of addressing the research question(s) and provides a deeper insight into free-living behaviour. It is proposed that it is through event-based analysis we can more clearly understand how behaviour is related to health and also how we can produce more relevant outcome measures.

The measurement of sedentary patterns and behaviors using the activPAL™ Professional physical activity monitor

Epidemiological studies have associated the negative effects of sedentary time and sedentary patterns on health indices. However, these studies have used methodologies that do not directly measure the sedentary state. Recent technological developments in the area of motion sensors have incorporated inclinometers, which can measure the inclination of the body directly, without relying on self-report or count thresholds. This paper aims to provide a detailed description of methodologies used to examine a range of relevant variables, including sedentary levels and patterns from an inclinometer-based motion sensor. The activPAL Professional physical activity logger provides an output which can be interpreted and used without the need for further processing and additional variables were derived using a custom designed MATLAB® computer program. The methodologies described have been implemented on a sample of 44 adolescent females, and the results of a range of daily physical activity and sedentary variables are described and presented. The results provide a range of objectively measured and objectively processed variables, including total time spent sitting/lying, standing and stepping, number and duration of daily sedentary bouts and both bed hours and non-bed hours, which may be of interest when making association between physical activity, sedentary behaviors and health indices.

Criterion and concurrent validity of the activPAL™ professional physical activity monitor in adolescent females

Background

The activPAL has been identified as an accurate and reliable measure of sedentary behaviour. However, only limited information is available on the accuracy of the activPAL activity count function as a measure of physical activity, while no unit calibration of the activPAL has been completed to date. This study aimed to investigate the criterion validity of the activPAL, examine the concurrent validity of the activPAL, and perform and validate a value calibration of the activPAL in an adolescent female population. The performance of the activPAL in estimating posture was also compared with sedentary thresholds used with the ActiGraph accelerometer.

Methodologies

Thirty adolescent females (15 developmental; 15 cross-validation) aged 15–18 years performed 5 activities while wearing the activPAL, ActiGraph GT3X, and the Cosmed K4B2. A random coefficient statistics model examined the relationship between metabolic equivalent (MET) values and activPAL counts. Receiver operating characteristic analysis was used to determine activity thresholds and for cross-validation. The random coefficient statistics model showed a concordance correlation coefficient of 0.93 (standard error of the estimate = 1.13). An optimal moderate threshold of 2997 was determined using mixed regression, while an optimal vigorous threshold of 8229 was determined using receiver operating statistics. The activPAL count function demonstrated very high concurrent validity (r = 0.96, p<0.01) with the ActiGraph count function. Levels of agreement for sitting, standing, and stepping between direct observation and the activPAL and ActiGraph were 100%, 98.1%, 99.2% and 100%, 0%, 100%, respectively.

Conclusions

These findings suggest that the activPAL is a valid, objective measurement tool that can be used for both the measurement of physical activity and sedentary behaviours in an adolescent female population.

Personalization algorithm for real-time activity recognition using PDA, wireless motion bands, and binary decision tree

Inactive and sedentary lifestyle is a major problem in many industrialized countries today. Automatic recognition of type of physical activity can be used to show the user the distribution of his daily activities and to motivate him into more active lifestyle. In this study, an automatic activity-recognition system consisting of wireless motion bands and a PDA is evaluated. The system classifies raw sensor data into activity types online. It uses a decision tree classifier, which has low computational cost and low battery consumption. The classifier parameters can be personalized online by performing a short bout of an activity and by telling the system which activity is being performed. Data were collected with seven volunteers during five everyday activities: lying, sitting/standing, walking, running, and cycling. The online system can detect these activities with overall 86.6% accuracy and with 94.0% accuracy after classifier personalization.