Seasonal changes in amount and patterns of physical activity in women

Three weeks of rehabilitation improves walking capacity but not daily physical activity in patients with multiple sclerosis with moderate to severe walking disability

Background

Patients with multiple sclerosis have low levels of physical activity. This is of concern because low activity levels are related to cardiovascular disease, poor walking ability, and reduced quality of life. The aim of this study was to evaluate the impact of rehabilitation on daily physical activity and walking capacity in patients with multiple sclerosis who have moderate to severe walking disability.

Methods

This exploratory, observational study of 24 patients with multiple sclerosis examined daily physical activity, walking capacity and fatigue before and after 3 weeks of inpatient rehabilitation. Inpatient rehabilitation included physiotherapy (30–60 min, 5 times/week), strength and endurance training (30–45 min, 3–5 times/week), occupational therapy (30 min, 2–3 times/week), and neuropsychological training (30 min, 2 times/week). There were no specific interventions to target daily levels of physical activity.

Results

Daily physical activity did not change after rehabilitation (physical activity: effect size = –0.23, 95% confidence interval (95% CI) 0.02‒0.62). There were significant improvements in walking capacity (Two-Minute Walk Test: effect size = 0.74, 95% CI 0.31‒1.16, +17 m, 20.2%) and mobility (Timed Up and Go Test: effect size = 0.65, 95% CI 0.22‒1.07, ‒2.1 s, 14.9%). Motor and cognitive fatigue (Fatigue Scale for Motor: effect size = 0.56, 95% CI 0.14‒0.99 and Cognitive Functions: effect size = 0.44, 95% CI 0.01‒0.86) improved significantly after rehabilitation.

Conclusion

Three weeks of rehabilitation improved walking capacity, but not daily physical activity, in patients with multiple sclerosis with moderate to severe walking disability. To increase physical activity, it may be necessary to add specific behavioural interventions to the rehabilitation programme. The intervention plan should include strategies to overcome personal and environmental barriers.

Seasonal Changes in Midlife Women'S Percentage Body Fat: A 1-Year Cohort Study

OBJECTIVE

The purpose of this longitudinal, observational study was to examine whether age and seasonal changes in sedentary activity (sedAct), moderate-to-vigorous physical activity (MVPA), and energy intake (EI) predict changes in body composition among midlife women. We hypothesized that reductions in MVPA and increases in sedAct and EI in winter, along with greater baseline age would predict increases in percentage body fat (%BF) across seasons.

DESIGN

This study used a longitudinal, within-subjects design. Setting: This study took place in Grand Forks, North Dakota.

PARTICIPANTS

Participants included 52 midlife women (aged 40-60 years) who were observed over the course of one year.

MEASUREMENTS

Percentage body fat measures were obtained via whole body Dual Energy X-ray absorptiometry. Participants were scanned once per season. We measured EI using the ASA24®. We used a GTX3 accelerometer to measure physical activity. Each season, participants wore the monitors for 7 days, 12 hours per day. All measures began in summer.

RESULTS

Results of hierarchical multiple regression (MR) analyses showed that age increases (β = 0.310, p = 0.021) and summer-to-fall increases in EI (β = 0.427, p = 0.002) predicted seasonal increases in %BF (R2 = .36, F(5, 42)= 4.66, p = 0.02). Changes in MVPA and sedAct were not significant predictors. Repeated measures ANCOVA revealed that summer (M = 37.7263, 95% CI [35.8377, 39.6149]) to winter (M = 38.1463, 95% CI [36.1983, 40.0942]) increases in %BF are not reversed by spring (M = 37.8761, 95% CI [35.9365, 39.8157]).

CONCLUSIONS

To minimize increases in %BF and maintain health, midlife women, particularly older women, should be encouraged to pay extra attention to their diet in the fall months.

Relationship between Seasonal Changes in Food Intake and Energy Metabolism, Physical Activity, and Body Composition in Young Japanese Women

We investigated seasonal changes in food intake, energy metabolism, and physical activity (PA) and explored their associations with body composition. In total, 28 women aged 20−23 years in the Kansai area of Japan participated in this year-long study spanning the winter, spring, and summer seasons. A dietary investigation was performed using the weight recording method, and the amount of histidine in the diet, which may be related to the regulation of energy intake, was calculated. Resting metabolic rate (RMR), body composition, and PA were measured using indirect calorimetry, bioelectrical impedance analysis, and uniaxial accelerometry, respectively. The results showed that energy intake was highest in winter, decreased significantly with increasing temperature, and decreased by 25% in summer. As the intake of histidine in the diet did not increase in summer, it did not seem to be involved in the suppression of energy intake. RMR was highest in winter and decreased significantly in summer by 20%. The amount of PA was low in winter, increased significantly in the spring, and decreased again in summer. Body weight increased in winter, with an accumulation of fat in the trunk and arms, and decreased in summer, with a reduction in the amount of fat. Greater energy intake and less PA in winter induced an increment in body weight despite the increase in RMR. There were no significant changes in lean body mass between the seasons; however, the muscle weight of the lower limbs increased significantly in spring and in summer compared with that in winter (p < 0.001). Thus, seasonal changes in food intake, energy metabolism, and PA occur, with resultant changes in the body composition under comfortable air-conditioned environments.

Association with Temperature Variability and Physical Activity, Sedentary Behavior, and Sleep in a Free-Living Population

The present study examines the temperature variability in physical activity (PA), sedentary behavior (SB), and sleep in a free-living population. A representative sample of 1235 adults (ages 21–70) from Iowa, U.S.A., wore a SenseWear Mini Armband (SWA) for a randomly assigned day. Koppen’s weather climate classification was used to precisely classify the temperature: cold (−13 to 32 °F), cool (32 to 50 °F), mild (50 to 64 °F), warm (64 to 73 °F), and hot (73 to 95 °F). The main effect of three-way ANOVA (age × gender × temperature) had differences for SB and sleep, with older adults having higher levels than younger adults (p < 0.05). However, moderate to vigorous PA (MVPA) did not vary systematically by age or gender, and contrary to expectations, the main effect of the weather was not significant for MVPA (p > 0.05). Participants spent more time participating in PA at cold than at hot temperatures. The results clarify the impact of temperature on shaping PA and SB patterns in adults. The variable impacts and differential patterns by age suggest that weather should be considered when interpreting differences in PA patterns in research or surveillance applications.

Annual, seasonal, cultural and vacation patterns in sleep, sedentary behaviour and physical activity: a systematic review and meta-analysis

Background

Time spent in daily activities (sleep, sedentary behaviour and physical activity) has important consequences for health and wellbeing. The amount of time spent varies from day to day, yet little is known about the temporal nature of daily activity patterns in adults. The aim of this review is to identify the annual rhythms of daily activity behaviours in healthy adults and explore what temporal factors appear to influence these rhythms.

Methods

Six online databases were searched for cohort studies exploring within-year temporal patterns (e.g. season effects, vacation, cultural festivals) in sleep, sedentary behaviour or physical activity in healthy 18 to 65-year-old adults. Screening, data extraction, and risk of bias scoring were performed in duplicate. Extracted data was presented as mean daily minutes of each activity type, with transformations performed as needed. Where possible, meta-analyses were performed using random effect models to calculate standardised mean differences (SMD).

Results

Of the 7009 articles identified, 17 studies were included. Studies were published between 2003 and 2019, representing 14 countries and 1951 participants, addressing variation in daily activities across season (n = 11), Ramadan (n = 4), vacation (n = 1) and daylight savings time transitions (n = 1). Meta-analyses suggested evidence of seasonal variation in activity patterns, with sleep highest in autumn (+ 12 min); sedentary behaviour highest in winter (+ 19 min); light physical activity highest in summer (+ 19 min); and moderate-to-vigorous physical activity highest in summer (+ 2 min) when compared to the yearly mean. These trends were significant for light physical activity in winter (SMD = − 0.03, 95% CI − 0.58 to − 0.01, P = 0.04). Sleep appeared 64 min less during, compared to outside Ramadan (non-significant). Narrative analyses for the impact of vacation and daylight savings suggested that light physical activity is higher during vacation and that sleep increases after the spring daylight savings transition, and decreases after the autumn transition.

Conclusions

Research into temporal patterns in activity behaviours is scarce. Existing evidence suggests that seasonal changes and periodic changes to usual routine, such as observing religious events, may influence activity behaviours across the year. Further research measuring 24-h time use and exploring a wider variety of temporal factors is needed.

Do weather parameters affect emergency room visits due to acute urinary retention?

Objective:

This study aimed to describe the effects of the various climate parameters on emergency room (ER) visits due to acute urinary retention (AUR).

Patients and methods:

This was a single-center retrospective analysis of the ER data of visits due to AUR in males and females between 2010 and 2017. We incorporated ER registries with data from the national meteorological service. Using multivariable logistic regression analyses, we assessed associations between climate parameters and the incidence of AUR.

Results:

A total of 1917 patients were admitted to the ER due to AUR during the study period, of whom 1706 (89%) were males and211 (11%) were females. Most AURs occurred in patients >70 years of age, with males on average being older than women (72.8 vs. 70.1 years old, p=0.01). Multivariable logistic regression analyses demonstrated that females had more AURs than men (odds ratio (OR)=1.3, 95% confidence interval (CI) 1.1–1.9, p=0.04) in spring. In all seasons except winter, a higher maximal temperature was associated with an increased risk of AUR, while in winter, a lower temperature was associated with an increased risk (OR=0.654, 95% CI 0.602–0.711, p<0.0001). Additionally, the following were associated with an increased AUR risk: increased wind speed and lower heat index during the spring, increased precipitation and a lower heat index during the autumn, and a higher heat index in the winter.

Conclusions:

Our data suggest that weather parameters might be associated with an increased AUR incidence in a Mediterranean coastline area, with maximal ambient temperature, wind speed, heat index, and precipitation playing a potential role.

Level of evidence:

6.

Seasonal Differences in the Cost and Engagement of Facebook Advertisements for a Physical Activity Smartphone App

PURPOSE

To evaluate the performance of Facebook advertisements for a physical activity smartphone app at different times of the year.

DESIGN

A repeated cross-sectional study examined the cost and engagement levels of advertisements during 3 time points: Post-Easter _{April-May 2019}, Pre-Summer _{October 2019}, and New Year _{January 2020 .}

SETTING

Advertisements were delivered on Facebook.

SUBJECTS

The target population was Australian females aged 25-60 years.

MEASURES

Cost was evaluated in terms of reach per dollar. Engagement was evaluated in terms of click-through and app downloads per reach.

ANALYSIS

ANOVA and Chi-square were used to assess differences in reach per dollar, click-through, and app downloads per reach between time points.

RESULTS

Reach per dollar was highest in Post-Easter, but declined in Pre-Summer and New Year (reach/$ 34.8 vs 31.5 vs 27.5; p = .004). Click-through was highest in New Year followed by Post-Easter, then Pre-Summer (click-through 3.2% vs 1.9% vs 1.2%; p < .001). New Year and Post-Easter advertisements achieved higher app downloads per reach than Pre-Summer (downloads 0.9% vs 0.7% vs 0.3%; p < .001).

CONCLUSION

Facebook advertisements were cheaper in the first time-point, and appear to be getting more expensive (i.e. declining reach/$). Advertisements in the New Year achieved the highest click-through and app downloads per reach, suggesting a useful time of year to promote physical activity products.

Seasons, weather, and device-measured movement behaviors: a scoping review from 2006 to 2020

BACKGROUND

This scoping review summarized research on (a) seasonal differences in physical activity and sedentary behavior, and (b) specific weather indices associated with those behaviors.

METHODS

PubMed, CINAHL, and SPORTDiscus were searched to identify relevant studies. After identifying and screening 1459 articles, data were extracted from 110 articles with 118,189 participants from 30 countries (almost exclusively high-income countries) on five continents.

RESULTS

Both physical activity volume and moderate-to-vigorous physical activity (MVPA) were greater in summer than winter. Sedentary behavior was greater in winter than either spring or summer, and insufficient evidence existed to draw conclusions about seasonal differences in light physical activity. Physical activity volume and MVPA duration were positively associated with both the photoperiod and temperature, and negatively associated with precipitation. Sedentary behavior was negatively associated with photoperiod and positively associated with precipitation. Insufficient evidence existed to draw conclusions about light physical activity and specific weather indices. Many weather indices have been neglected in this literature (e.g., air quality, barometric pressure, cloud coverage, humidity, snow, visibility, windchill).

CONCLUSIONS

The natural environment can influence health by facilitating or inhibiting physical activity. Behavioral interventions should be sensitive to potential weather impacts. Extreme weather conditions brought about by climate change may compromise health-enhancing physical activity in the short term and, over longer periods of time, stimulate human migration in search of more suitable environmental niches.

Effect of Adherence to Physical Exercise on Cardiometabolic Profile in Postmenopausal Women

Background: Menopause is associated with negative cardiovascular adaptations related to estrogen depletion, which could be counteracted by physical exercise (PhE). However, the impact of total adherence-rate (TA) to PhE and sedentary time (SedT) on cardiometabolic profile in this population has not been elucidated. Methods: For 13-weeks, 43 women (57.1 ± 4.7 years) participated in a 4-days-a-week moderate-intensity walking training. They underwent laboratory, anthropometric and echocardiographic assessment, before and after training (T0-T1). Spontaneous physical activity (PhA) was assessed with a portable multisensory device. The sample was divided according to TA to PhE program: <70% (n = 17) and ≥70% (n = 26). Results: TA ≥ 70% group experienced a significant T1 improvement of relative wall thickness (RWT), diastolic function, VO2max, cortisol, cortisol/dehydroandrostenedione-sulphate ratio and serum glucose. After adjusting for SedT and 10-min bouts of spontaneous moderate-to-vigorous PhA, TA ≥ 70% showed the most significant absolute change of RWT and diastolic function, body mass index, weight and cortisol. TA ≥ 70% was major predictor of RWT and cortisol improvement. Conclusions: In a group of untrained, postmenopausal women, a high TA to a 13-weeks aerobic PhE program confers a better improvement in cardiometabolic profile, regardless of SedT and PhA levels.

Association of Pain and Steps Per Day in Persons With Mild-to-Moderate, Symptomatic Knee Osteoarthritis: A Mixed-Effects Models Analysis of Multiple Measurements Over Three Years

OBJECTIVE

Pain is a consistently reported barrier to physical activity by persons with knee osteoarthritis (OA). Nonetheless, few studies of knee OA have investigated the association of pain with daily walking levels. The current study assessed the relationship of 2 distinct measures of knee pain with objectively measured physical activity in adults with knee OA.

METHODS

This was a longitudinal, observational investigation of 59 individuals (48 women; mean ± SD age 61.1 ± 6.4 years, mean ± SD body mass index 28.1 ± 5.6 kg/m² ) with clinical knee OA. Data were collected every 3 months for up to 3 years. Physical activity was characterized as the average steps per day taken over at least 3 days, mea-sured by accelerometry. Pain was measured using 2 patient-administered questionnaires: the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS-pain) and the P4 pain scale (P4-pain). Mixed-effects models determined the association between pain and physical activity levels (over covariates) among adults with knee OA (α = 0.05).

RESULTS

All covariates (age [β = -3.65, P < 0.001], body mass index [β = -3.06, P < 0.001], season [spring/fall β = -6.91, P = 0.002; winter β = -14.92, P < 0.001]) were predictors of physical activity. Neither the inverted KOOS-pain (β = 0.04, P = 0.717) nor P4-pain (β = -0.37, P = 0.264) was associated with physical activity.

CONCLUSION

Knee pain is not associated with daily walking levels in persons with mild-to-moderate, symptomatic knee OA. While pain management remains an important target of interventions, strategies to increase steps per day in this population should focus on overcoming potentially more crucial barriers to activity participation.

Seasonal variation in body mass, body composition and activity-induced energy expenditure: a long-term study

BACKGROUND/OBJECTIVES

Seasonal variation in body mass is a model for the study of body mass regulation. Here a long-term study is presented on body mass, body composition, and activity-induced energy expenditure in a subject with a large seasonal variation in body mass of about 3.0 kg.

SUBJECT/METHODS

Body mass was assessed daily over >20 consecutive years. Daily assessment of activity-induced energy expenditure was performed over the last 10 years. Body composition was assessed monthly for 1 year in the middle and at the end of the observation interval. Additionally, data were compared with data on body composition, resting energy expenditure, and total daily energy expenditure of the same subject as a participant in published studies.

RESULTS

Body mass showed a pronounced seasonal variation, associated with a synchronous variation in physical activity. Body mass peaked in the cold winter months when physical activity reached the lowest annual value and decreased to the lowest value in mid-summer when daily physical activity peaked. The seasonal variation in body mass consisted mainly of body fat. Longitudinally, over the past 8 years of the observation interval, average fat-free mass showed a decrease of 1.0 kg and fat mass increased 0.8 kg.

CONCLUSIONS

In a subject with a pronounced seasonal variation in physical activity, activity-induced variation in energy requirement was covered by an annual variation in body mass, mainly as fat. Maintenance of activity-induced energy expenditure did not protect against loss of fat-free body mass with advancing age.

Geographical variation and predictors of physical activity level in adults with congenital heart disease

Background

Physical activity is important to maintain and promote health. This is of particular interest in patients with congenital heart disease (CHD) where acquired heart disease should be prevented. The World Health Organization (WHO) recommends a minimum of 2.5 h/week of physical activity exceeding 3 metabolic equivalents (METS) to achieve positive health effects. It is unknown whether physical activity levels (PAL) in adult CHD patients differ by country of origin.

Methods

3896 adults with CHD recruited from 15 countries over 5 continents completed self-reported instruments, including the Health Behaviour Scale (HBS-CHD), within the APPROACH-IS project. For each patient, we calculated whether WHO recommendations were achieved or not. Associated factors were investigated using Generalized Linear Mixed Models.

Results

On average, 31% reached the WHO recommendations but with a great variation between geographical areas (India: 10%–Norway: 53%). Predictors for physical activity level in line with the WHO recommendations, with country of residence as random effect, were male sex (OR 1.78, 95%CI 1.52–2.08), NYHA-class I (OR 3.10, 95%CI 1.71–5.62) and less complex disease (OR 1.46, 95%CI 1.16–1.83). In contrast, older age (OR 0.97, 95%CI 0.96–0.98), lower educational level (OR 0.41, 95%CI 0.26–0.64) and being unemployed (OR 0.57, 95%CI 0.42–0.77) were negatively associated with reaching WHO recommendations.

Conclusions

A significant proportion of patients with CHD did not reach the WHO physical activity recommendations. There was a large variation in physical activity level by country of origin. Based on identified predictors, vulnerable patients may be identified and offered specific behavioral interventions.

Seasonal variations in urinary calcium, volume, and vitamin d in kidney stone formers

OBJECTIVES

To investigate the seasonal variations in urinary calcium, serum vitamin D, and urinary volume in patients with a history of nephrolithiasis.

MATERIALS AND METHODS

Patients included were those who completed a 24-hour urine metabolic evaluation on two occasions; one in summer (June-Aug) and one in winter (Nov-Jan), and who had not started any medications or been instructed on dietary modifications in the interval between the two tests that may have impacted the results. Patients were excluded if they were on thiazide diuretics or were taking calcium and / or Vitamin D supplementation. Welch's t-test was used to compare the difference in average summer and winter values. Unpaired Student t-test was used to compare baseline parameters (age, BMI), and Paired Student t-test was used to compare average seasonal measurements in men vs. women.

RESULTS

136 patients were identified who were not taking calcium or vitamin D supplements or thiazide diuretics, and who were not instructed on dietary modifications in the interval between the two measured parameters. No significant differences were observed when comparing male to female baseline parameters of age or BMI (Table-1). Average 24-hour urine calcium was higher (226.60) in the winter than in summer (194.18) and was significant in males (p = 0.014) and females (p < 0.001). No significant seasonal difference was seen in 24-hour urine volume or serum vitamin D levels.

CONCLUSIONS

Urinary calcium is higher in winter months compared to summer months. As such, tailoring medical preventative strategies to the time of year may be helpful.

Seasonality of physical activity, sedentary behavior, and sleep in a middle-aged and elderly population: The Rotterdam study

INTRODUCTION

Physical activity (PA) and sedentary behavior (SB) have seasonal patterns. It remains unclear how these patterns are associated with sleep, meteorological factors, and health.

METHODS

Activity levels were continuously measured with an accelerometer for seven days between July 2011 and May 2016, among middle-aged (50-64 years), young-elderly (65-74 years) and old-elderly (≥75 years) participants of a population-based Dutch cohort study (n = 1116). Meteorological factors (ambient temperature, wind speed, sunlight hours, precipitation, and minimum visibility) were locally recorded. We first examined the seasonality of PA, SB, and nighttime sleep, stratified by age group. Second, we examined the influence of meteorological factors. Third, we modeled the potential seasonality of the all-cause mortality risk due to the seasonality of PA and SB, by using previously published relative risks.

RESULTS

Levels of light and moderate-to-vigorous PA were higher in summer than in winter among middle-aged (seasonal variation = 18.1 and 14.8 min/day) and young-elderly adults (12.8 and 8.6 min/day). The pattern was explained by ambient temperature and sunlight hours. Nighttime sleep was 31.8 min/day longer in winter among middle-aged adults. SB did not show a seasonal pattern. No seasonality in activity levels was observed among old-elderly adults. The all-cause mortality risk may be higher in winter than in summer due to the accumulation of low levels of moderate to vigorous PA and high levels of SB.

CONCLUSION

PA has a larger degree of seasonality than SB and nighttime sleep among middle-aged and young-elderly adults. SB appears strongly ingrained in daily routine. Recommending the interruption of SB with light PA might be a good starting point for public health institutions.

The Seasonal Periodicity of Healthy Contemplations About Exercise and Weight Loss: Ecological Correlational Study

Background

Lack of physical activity and weight gain are two of the biggest drivers of health care costs in the United States. Healthy contemplations are required before any changes in behavior, and a recent study has shown that they have underlying periodicities.

Objective

The aim of this study was to examine seasonal variations in state-by-state interest in both weight loss and increasing physical activity, and how these variations were associated with geographic latitude using Google Trends search data for the United States.

Methods

Internet search query data were obtained from Google Trends (2004-2016). Time series analysis (every 2 weeks) was performed to determine search volume (normalized to overall search intensity). Seasonality was determined both by the difference in search volumes between winter (December, January, and February) and summer (June, July, and August) months and by the amplitude of cosinor analysis.

Results

Exercise-related searches were highest during the winter months, whereas weight loss contemplations showed a biphasic pattern (peaking in the summer and winter months). The magnitude of the seasonal difference increased with increasing latitude for both exercise (R²=.45, F_1,49=40.09, beta=−.671, standard deviation [SD]=0.106, P<.001) and weight loss (R²=.24, F_1,49=15.79, beta=−.494, SD=0.124, P<.001) searches.

Conclusions

Healthy contemplations follow specific seasonal patterns, with the highest contemplations surrounding exercise during the winter months, and weight loss contemplations peaking during both winter and summer seasons. Knowledge of seasonal variations in passive contemplations may potentially allow for more efficient use of public health campaign resources.

Comparison of Summer and Winter Objectively Measured Physical Activity and Sedentary Behavior in Older Adults: Age, Gene/Environment Susceptibility Reykjavik Study

In Iceland, there is a large variation in daylight between summer and winter. The aim of the study was to identify how this large variation influences physical activity (PA) and sedentary behavior (SB). Free living PA was measured by a waist-worn accelerometer for one week during waking hours in 138 community-dwelling older adults (61.1% women, 80.3 ± 4.9 years) during summer and winter months. In general, SB occupied about 75% of the registered wear-time and was highly correlated with age (β = 0.36). Although the differences were small, more time was spent during the summer in all PA categories, except for the moderate-to-vigorous PA (MVPA), and SB was reduced. More lifestyle PA (LSPA) was accumulated in ≥5-min bouts during summer than winter, especially among highly active participants. This information could be important for policy makers and health professionals working with older adults. Accounting for seasonal difference is necessary in analyzing SB and PA data.

Impact of educational interventions on primary prevention of cardiovascular disease: A systematic review with a focus on physical activity

Background: Evidence from epidemiological and experimental studies illustrates the beneficial impact of healthy lifestyle behaviours on cardiovascular risk.

Objectives: To assess the effectiveness of primary care health education interventions designed to promote healthy lifestyles on physical activity levels and cardiovascular risk.

Methods: A computer-aided search on PubMed and Scopus was performed to identify relevant studies published from January 2000 to October 2016. Two authors independently selected studies for inclusion and extracted data, including intervention characteristics and outcome measures, namely physical activity and cardiovascular risk or risk factors.

Results: Of the 212 identified studies, 15 met the inclusion criteria. The 15 studies enrolled 6727 participants; the sample size varied between 74 and 878 adults. Fourteen studies assessed physical activity by questionnaire and only one study used accelerometry. Eight of the 15 studies showed improvements in the physical activity levels after the intervention, ranging from 5% to 26% in those where significant changes between groups were detected. Most studies reported significant positive effects of the health education interventions on cardiovascular risk factors, mainly on lipid profile, blood pressure and cardiovascular risk score.

Conclusion: The health education interventions, in primary care, seem to improve daily physical activity, cardiovascular risk factors and risk score.

Usability of a Medication Event Reminder Monitor System (MERM) by Providers and Patients to Improve Adherence in the Management of Tuberculosis

Poor initiation and implementation and premature discontinuation of anti-tuberculous therapy, all forms of nonadherence, are major reasons for treatment failure, the development of drug-resistant tuberculosis, and transmission to other non-infected individuals. Directly Observed Therapy (DOT) has been the worldwide standard, but implementation of DOT is burdensome for providers and patients, especially in resource-limited settings, where most of the burden of active TB is located. Among the alternatives to DOT is electronic monitoring (EM) of drug dosing histories. Here we report a usability study of a newly-designed, modular electronic monitor product, called the MERM (Medication Event and Reminder Monitor), that is compatible with TB medication formats and supply chains in resource-limited settings. This study, done in a rural setting in China, showed that the use of the MERM for EM of TB medications was associated with a high degree of user performance, acceptability, and satisfaction among both TB patients and medical staff. Based on these data, EM is becoming the standard of care for drug-susceptible TB patients in China and scaled implementations in several other countries with high TB burden have begun. In addition, the MERM is being used in MDR-TB patients and in clinical trials involving patients with TB/HIV and latent TB.

Walking training and cortisol to DHEA-S ratio in postmenopause: An intervention study

The literature indicates that the plasma cortisol-to-dehydroepiandrosterone-sulfate (DHEA-S) ratio is a marker of health status after menopause, when a decline in both estrogen and DHEA-S and an increase in cortisol occur. An increase in the cortisol-to-DHEA-S ratio has been positively correlated with metabolic syndrome, all-cause mortality, cancer, and other diseases. The aim of this study was to investigate the effects of a walking program on the plasma cortisol-to-DHEA-S ratio in postmenopausal women. Fifty-one postmenopausal women participated in a 13-week supervised walking program, in the metropolitan area of Pescara (Italy), from June to September 2013. Participants were evaluated in April-May and September-October of the same year. The linear mixed model showed that the variation of the log₁₀Cortisol-to-log₁₀DHEA-S ratio was associated with the volume of exercise (p = .03). Participants having lower adherence to the walking program did not have a significantly modified log₁₀Cortisol or log₁₀DHEA-S, while those having the highest adherence had a significant reduction in log₁₀Cortisol (p = .016) and a nearly significant increase in log₁₀DHEA-S (p = .084). Walking training appeared to reduce the plasma log₁₀Cortisol-to-log₁₀DHEA-S ratio, although a minimum level of training was necessary to achieve this significant reduction.

Comparison between logbook-reported and objectively-assessed physical activity and sedentary time in breast cancer patients: an agreement study

Background

Increasing physical activity (PA) and decreasing sedentary time (ST) have important health effects among breast cancer patients, a growing population group. PA and sedentary behaviors are complex multi-dimensional behaviors and are challenging to monitor accurately. To date few studies have compared self-reports and objective measurement in assessing PA and ST in women undergoing breast cancer treatments. The aim of the present study was to compare self-reports and objective measures for assessing daily time spent in moderate-intensity physical activity (MPA), vigorous-intensity physical activity (VPA) and ST in women undergoing breast cancer treatments.

Methods

Baseline data from 65 women with breast cancer scheduled to undergo adjuvant treatment was included. Daily time spent in MPA, VPA and ST was assessed by a study-specific logbook and the SenseWear Armband mini (SWA). The level of agreement between the two measurement methods was then determined by performing Bland-Altman plots with limits of agreements, and calculating Spearman’s rank correlation coefficients.

Results

The mean difference between the logbook and SWA with limits of agreement was 14 (±102) minutes for MPA, 1 (±21) minute for VPA and −196 (±408) minutes for ST, respectively. The logbook reported an average of 34 and 50% higher values than the SWA for MPA and VPA, as well as an average of 27% lower values for ST (P < 0.05). The Spearman’s rank correlation coefficients showed that the differences between the methods increased as the average amount of time spent in PA and ST increased (P < 0.01).

Conclusions

The results imply that the two measurement methods have limited agreement and cannot be used interchangeably.

Validation of the SQUASH Physical Activity Questionnaire in a Multi-Ethnic Population: The HELIUS Study

PURPOSE

To investigate the reliability and validity of the SQUASH physical activity (PA) questionnaire in a multi-ethnic population living in the Netherlands.

METHODS

We included participants from the HELIUS study, a population-based cohort study. In this study we included Dutch (n = 114), Turkish (n = 88), Moroccan (n = 74), South-Asian Surinamese (n = 98) and African Surinamese (n = 91) adults, aged 18-70 years. The SQUASH was self-administered twice to assess test-re-test reliability (mean interval 6-7 weeks) and participants wore an accelerometer and heart rate monitor (Actiheart) to enable assessment of construct validity.

RESULTS

We observed low test-re-test reliability; Intra class correlation coefficients ranged from low (0.05 for moderate/high intensity PA in African Surinamese women) to acceptable (0.78 for light intensity PA in Moroccan women). The discrepancy between self-reported and measured PA differed on the basis of the intensity of activity: self-reported light intensity PA was lower than measured but self-reported moderate/high intensity PA was higher than measured, with wide limits of agreement. The discrepancy between questionnaire and Actiheart measures of moderate intensity PA did not differ between ethnic minority and Dutch participants with correction for relevant confounders. Additionally, the SQUASH overestimated the number of participants meeting the Dutch PA norm; Cohen's kappas for the agreement were poor, the highest being 0.30 in Dutch women.

CONCLUSION

We found considerable variation in the test-re-test reliability and validity of self-reported PA with no consistency based on ethnic origin. Our findings imply that the SQUASH does not provide a valid basis for comparison of PA between ethnic groups.

Personal power-frequency magnetic field exposure in women recruited at an infertility clinic: association with physical activity and temporal variability

Current epidemiologic approaches for studying exposure to power-frequency magnetic fields and the risk of miscarriage are potentially biased due to lack of attention to the relationship of exposure with physical activity and within-individual variability in exposures over time. This analysis examines these two issues using data from a longitudinal pilot study of 40 women recruited from an infertility clinic that contributed data for up to three 24-h periods separated by a median of 3.6 weeks. Physical activity was positively associated with peak exposure metrics. Higher physical activity within environments did not necessarily lead to higher peak exposures, suggesting that movement between and not within environments increases one's probability of encountering a high field source. Peak compared with central tendency metrics were more variable over time. Future epidemiology studies associated with peak exposure metrics should adjust for physical activity and collect more than 1 d of exposure measurement to reduce bias.

Tweet for health: using an online social network to examine temporal trends in weight loss-related posts

Few studies have used social networking sites to track temporal trends in health-related posts, particularly around weight loss. To examine the temporal relationship of Twitter messages about weight loss over 1 year (2012). Temporal trends in #weightloss mentions and #fitness, #diet, and #health tweets which also had the word "weight" in them were examined using three a priori time periods: (1) holidays: pre-winter holidays, holidays, and post-holidays; (2) Season: winter and summer; and (3) New Year's: pre-New Year's and post-New Year's. Regarding #weightloss, there were 145 (95 % CI 79, 211) more posts/day during holidays and 143 (95 % CI 76, 209) more posts/day after holidays as compared to 480 pre-holiday posts/day; 232 (95 % CI 178, 286) more posts/day during the winter versus summer (441 posts/day); there was no difference in posts around New Year's. Examining social networks for trends in health-related posts may aid in timing interventions when individuals are more likely to be discussing weight loss.

Television Viewing Time and Measured Cardiorespiratory Fitness in Adult Women

Purpose.

This study assessed the relationship between television viewing time and measured cardiorespiratory fitness and the influence of various potential confounders.

Design.

Cross-sectional.

Setting.

Intermountain West.

Subjects.

The sample was composed of 302 nonsmoking women aged 40.2 ± 3.0 years, with ∼90% Caucasian and 82% married.

Measures.

TV viewing was assessed by using a questionnaire, and cardiorespiratory fitness was measured by using a graded, maximum treadmill test. Physical activity (PA) was evaluated by using accelerometers for 7 days, and body fat percentage (BF%) was measured by using the Bod Pod.

Analysis.

Analysis of variance and partial correlation.

Results.

VO2max of Frequent (≥3 h/d) TV viewers (32.6 ± 6.4 mL/kg/min) was significantly lower than that of both Moderate (1–2 h/d) (36.2 ± 7.2 mL/kg/min) or Infrequent (<1 h/d) (36.5 ± 6.5 mL/kg/min) viewers (F= 8.0, p = .0004). The Infrequent and Moderate groups did not differ in VO2max. Age, education, body mass index, and season of assessment had no influence on the relationship when controlled statistically. Adjusting for PA (F = 4.2, p = .0157) and BF% (F = 5.0, p = .0071) weakened the relationship by 59% and 58%, respectively, but the relationships remained significant. After controlling for both PA and BF% simultaneously (F = 2.9, p = .0572), the relationship was weakened by 81% and was only borderline significant.

Conclusion.

Female Frequent TV viewers have significantly lower cardiorespiratory fitness levels than Moderate or Infrequent viewers. This association appears to be largely a function of differences in levels of PA and BF%.

Temporal variability of daily personal magnetic field exposure metrics in pregnant women

Recent epidemiology studies of power-frequency magnetic fields and reproductive health have characterized exposures using data collected from personal exposure monitors over a single day, possibly resulting in exposure misclassification due to temporal variability in daily personal magnetic field exposure metrics, but relevant data in adults are limited. We assessed the temporal variability of daily central tendency (time-weighted average, median) and peak (upper percentiles, maximum) personal magnetic field exposure metrics over 7 consecutive days in 100 pregnant women. When exposure was modeled as a continuous variable, central tendency metrics had substantial reliability, whereas peak metrics had fair (maximum) to moderate (upper percentiles) reliability. The predictive ability of a single-day metric to accurately classify participants into exposure categories based on a weeklong metric depended on the selected exposure threshold, with sensitivity decreasing with increasing exposure threshold. Consistent with the continuous measures analysis, sensitivity was higher for central tendency metrics than for peak metrics. If there is interest in peak metrics, more than 1 day of measurement is needed over the window of disease susceptibility to minimize measurement error, but 1 day may be sufficient for central tendency metrics.

The Use of Text Messaging to Promote Physical Activity in Working Women: A Randomized Controlled Trial

BACKGROUND

The study evaluated the effects of a text message intervention on physical activity in adult working women.

METHODS

Eighty-seven participants were randomized to an intervention (n = 41) or control group (n = 46). Pedometer step counts and measures of self-efficacy were collected at baseline, 12 weeks, and 24 weeks. Intervention participants received approximately 3 text messages per week that were motivational, informational, and specific to performing physical activity.

RESULTS

ANCOVA results showed a significant difference between groups for mean steps per day at 12 weeks (6540.0 vs. 5685.0, P = .01) and no significant difference at 24 weeks (6867.7 vs. 6189.0, P = .06). There was no change in mean step counts during or after the intervention compared with baseline. There was a significant difference between groups for mean self-efficacy scores at 12 weeks (68.5 vs. 60.3, P = .02) and at 24 weeks (67.3 vs. 59.0, P = .03).

CONCLUSIONS

Intervention participants had higher step counts after 12 and 24 weeks compared with a control group; however, the difference was significant only at the midpoint of the intervention and was attributable to a decrease in steps for the control group. Text messaging did not increase step counts but may be a cost-effective tool for maintenance of physical activity behavior.

Cross-sectional associations of objectively measured physical activity, cardiorespiratory fitness and anthropometry in European adults

OBJECTIVE

To quantify the independent associations between objectively measured physical activity (PA), cardiorespiratory fitness (CRF), and anthropometry in European men and women.

METHODS

2,056 volunteers from 12 centers across Europe were fitted with a heart rate and movement sensor at 2 visits 4 months apart for a total of 8 days. CRF (ml/kg/min) was estimated from an 8 minute ramped step test. A cross-sectional analysis of the independent associations between objectively measured PA (m/s(2)/d), moderate and vigorous physical activity (MVPA) (%time/d), sedentary time (%time/d), CRF, and anthropometry using sex stratified multiple linear regression was performed.

RESULTS

In mutually adjusted models, CRF, PA, and MVPA were inversely associated with all anthropometric markers in women. In men, CRF, PA, and MVPA were inversely associated with BMI, whereas only CRF was significantly associated with the other anthropometric markers. Sedentary time was positively associated with all anthropometric markers, however, after adjustment for CRF significant in women only.

CONCLUSION

CRF, PA, MVPA, and sedentary time are differently associated with anthropometric markers in men and women. CRF appears to attenuate associations between PA, MVPA, and sedentary time. These observations may have implications for prevention of obesity.

Validity of electronically administered Recent Physical Activity Questionnaire (RPAQ) in ten European countries

OBJECTIVE

To examine the validity of the Recent Physical Activity Questionnaire (RPAQ) which assesses physical activity (PA) in 4 domains (leisure, work, commuting, home) during past month.

METHODS

580 men and 1343 women from 10 European countries attended 2 visits at which PA energy expenditure (PAEE), time at moderate-to-vigorous PA (MVPA) and sedentary time were measured using individually-calibrated combined heart-rate and movement sensing. At the second visit, RPAQ was administered electronically. Validity was assessed using agreement analysis.

RESULTS

RPAQ significantly underestimated PAEE in women [median(IQR): 34.9 (22.3, 52.8) vs. 40.6 (32.4, 50.9) kJ/kg/day, 95%LoA: -44.4, 66.1 kJ/kg/day) and overestimated PAEE in men [45.9 (30.6, 71.1) vs. 45.5 (34.1, 57.6) kJ/kg/day, 95%LoA: -44.8, 102.6 kJ/kg/day]. Using individualised definition of 1MET, RPAQ significantly underestimated MVPA in women [median(IQR): 63.7 (30.5, 126.9) vs. 73.6 (47.8, 107.2) min/day, 95%LoA: -127.4, 311.9 min/day] and overestimated MVPA in men [90.0 (42.3, 188.6) vs. 83.3 (55.1, 125.0) min/day, 95%LoA: -134.8, 427.3 min/day]. Correlations (95%CI) between subjective and objective estimates were statistically significant [PAEE: women, rho = 0.20 (0.15-0.26); men, rho = 0.37 (0.30-0.44); MVPA: women, rho = 0.18 (0.13-0.24); men, rho = 0.31 (0.24-0.38)]. When using non-individualised definition of 1MET (3.5 mlO2/kg/min), MVPA was substantially overestimated (16 min/day, and 32 min/day in women and men, respectively). Revisiting occupational intensity assumptions in questionnaire estimation algorithms with occupational group-level empirical distributions reduced median PAEE-bias in manual (38.8 kJ/kg/day vs. 6.8 kJ/kg/day, p<0.001) and heavy manual workers (63.6 vs. -2.8 kJ/kg/day, p<0.001) in an independent hold-out sample [corrected].

CONCLUSION

Relative validity of RPAQ-derived PAEE and MVPA is comparable to previous studies but underestimation of PAEE is smaller. Electronic RPAQ may be used in large-scale epidemiological studies including surveys, providing information on all domains of PA.

The improved physical activity index for measuring physical activity in EPIC Germany

In the European Investigation into Cancer and Nutrition study (EPIC), physical activity (PA) has been indexed as a cross-tabulation between PA at work and recreational activity. As the proportion of non-working participants increases, other categorization strategies are needed. Therefore, our aim was to develop a valid PA index for this population, which will also be able to express PA continuously. In the German EPIC centers Potsdam and Heidelberg, a clustered sample of 3,766 participants was re-invited to the study center. 1,615 participants agreed to participate and 1,344 participants were finally included in this study. PA was measured by questionnaires on defined activities and a 7-day combined heart rate and acceleration sensor. In a training sample of 433 participants, the Improved Physical Activity Index (IPAI) was developed. Its performance was evaluated in a validation sample of 911 participants and compared with the Cambridge Index and the Total PA Index. The IPAI consists of items covering five areas including PA at work, sport, cycling, television viewing, and computer use. The correlations of the IPAI with accelerometer counts in the training and validation sample ranged r = 0.40–0.43 and with physical activity energy expenditure (PAEE) r = 0.33–0.40 and were higher than for the Cambridge Index and the Total PA Index previously applied in EPIC. In non-working participants the IPAI showed higher correlations than the Cambridge Index and the Total PA Index, with r = 0.34 for accelerometer counts and r = 0.29 for PAEE. In conclusion, we developed a valid physical activity index which is able to express PA continuously as well as to categorize participants according to their PA level. In populations with increasing rates of non-working people the performance of the IPAI is better than the established indices used in EPIC.

Theory of planned behaviour variables and objective walking behaviour do not show seasonal variation in a randomised controlled trial

BACKGROUND

Longitudinal studies have shown that objectively measured walking behaviour is subject to seasonal variation, with people walking more in summer compared to winter. Seasonality therefore may have the potential to bias the results of randomised controlled trials if there are not adequate statistical or design controls. Despite this there are no studies that assess the impact of seasonality on walking behaviour in a randomised controlled trial, to quantify the extent of such bias. Further there have been no studies assessing how season impacts on the psychological predictors of walking behaviour to date. The aim of the present study was to assess seasonal differences in a) objective walking behaviour and b) Theory of Planned Behaviour (TPB) variables during a randomised controlled trial of an intervention to promote walking.

METHODS

315 patients were recruited to a two-arm cluster randomised controlled trial of an intervention to promote walking in primary care. A series of repeated measures ANCOVAs were conducted to examine the effect of season on pedometer measures of walking behaviour and TPB measures, assessed immediately post-intervention and six months later. Hierarchical regression analyses were conducted to assess whether season moderated the prediction of intention and behaviour by TPB measures.

RESULTS

There were no significant differences in time spent walking in spring/summer compared to autumn/winter. There was no significant seasonal variation in most TPB variables, although the belief that there will be good weather was significantly higher in spring/summer (F = 19.46, p < .001). Season did not significantly predict intention or objective walking behaviour, or moderate the effects of TPB variables on intention or behaviour.

CONCLUSION

Seasonality does not influence objectively measured walking behaviour or psychological variables during a randomised controlled trial. Consequently physical activity behaviour outcomes in trials will not be biased by the season in which they are measured. Previous studies may have overestimated the extent of seasonality effects by selecting the most extreme summer and winter months to assess PA. In addition, participants recruited to behaviour change interventions might have higher levels of motivation to change and are less affected by seasonal barriers.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN95932902.

Obesity increases risk of declining physical activity over time in women: a prospective cohort study

OBJECTIVE

Research indicates that risk of obesity increases as physical activity (PA) decreases; however, the reciprocal effect has been rarely studied. The present investigation was conducted to determine the contribution of obesity on objectively measured PA over 20 months.

DESIGN AND METHODS

A prospective cohort design with 254 middle-aged women was employed. Body fat percentage (BF%) was measured using Bod Pod, and obesity was defined as BF% ≥32%. PA was assessed objectively using 7-day accelerometry at baseline and ∼20 months later at follow-up.

RESULTS

Of the 254 subjects, 124 were obese (49%) at baseline. Mean BF% was 32.1 ± 7.8 and average age was 41.7 ± 3.1 years. Mean weekly PA was 2.79 ± 0.85 million activity counts for all participants. Over the 20-month period, PA decreased significantly more in obese women (-8.1% ± 27.1%) than in nonobese women (0.3% ± 31.7%) after adjusting for confounders (F = 5.3, P = 0.022). Moderate plus vigorous PA levels also decreased more in obese women (-28.1 ± 73.6 min/week) than in nonobese women (-5.9 ± 66.8 min/week), after adjusting for covariates (F = 7.84; P = 0.0055).

CONCLUSIONS

It appears that obese women tend to reduce PA over time at a faster rate than nonobese women. Evidently, obesity is a risk factor for decreasing PA over time in middle-aged women.

Does the type of weight loss diet affect who participates in a behavioral weight loss intervention? A comparison of participants for a plant-based diet versus a standard diet trial

Studies have found that people following plant-based eating styles, such as vegan or vegetarian diets, often have different demographic characteristics, eating styles, and physical activity (PA) levels than individuals following an omnivorous dietary pattern. There has been no research examining if there are differences in these characteristics among people who are willing to participate in a weight loss intervention using plant-based dietary approaches as compared to a standard reduced calorie approach, which does not exclude food groups. The present study compared baseline characteristics (demographics, dietary intake, eating behaviors (Eating Behavior Inventory), and PA (Paffenbarger Physical Activity Questionnaire)) of participants enrolling in two different 6-month behavioral weight loss studies: the mobile Pounds Off Digitally (mPOD) study, which used a standard reduced calorie dietary approach and the New Dietary Interventions to Enhance the Treatments for weight loss (New DIETs) study, which randomized participants to follow one of five different dietary approaches (vegan, vegetarian, pesco-vegetarian, semi-vegetarian, or omnivorous diets). There were no differences in baseline demographics with the exception of New DIETs participants being older (48.5±8.3years versus 42.9±11.2, P=0.001) and having a higher Body Mass Index (BMI, 35.2±5.3kg/m(2) versus 32.6±4.7kg/m(2), P=0.001) than mPOD participants. In age- and BMI-adjusted models, there were no differences in EBI scores or in any dietary variables, with the exception of vitamin C (85.6±5.9mg/d mPOD versus 63.4±7.4mg/d New DIETs, P=0.02). New DIETs participants reported higher levels of intentional PA/day (180.0±18.1kcal/d) than mPOD participants (108.8±14.4kcal/d, P=0.003), which may have been the result of New DIETs study recommendations to avoid increasing or decreasing PA during the study. The findings of this study demonstrate that using plant-based dietary approaches for weight loss intervention studies does not lead to a population which is significantly different from who enrolls in a standard, behavioral weight loss study using a reduced calorie dietary approach.

Associations of season and region on objectively assessed physical activity and sedentary behaviour

Seasonal and regional variation may influence physical activity (PA) patterns. These associations are in need of further investigation. The objective of the current study was to examine the association of season and region on objectively measured PA. The study was designed as a cross-sectional study with 1172 participants living in Sweden. Data on PA were collected throughout a calendar year using accelerometry. Regions were categorised as south (Götaland), central (Svealand) and north (Norrland). Outcome variables included accelerometer-measured mean counts per minute, sedentary time and time in low intensity and moderate-intensity physical activity (MVPA) or greater. ANCOVA was used to determine the associations of season and region with PA, adjusting for sex, age, body mass index (BMI) and education. The results showed that during the Spring season more time was spent in MVPA than during the Autumn. For participants living in the south of Sweden, a significant trend for season was found for MVPA, with Spring having the highest MVPA (P = 0.025). Season had a borderline significant association with MVPA or higher intensity activities (P = 0.051). No significant effects of region or season on total PA, low-intensity PA and sedentary periods of time were observed. The results indicate that studies conducted in a population living in high latitudes, may not be significantly affected by seasonality or region when assessing PA.

Clinically meaningful change estimates for the six-minute walk test and daily activity in individuals with chronic heart failure

PURPOSE

The purpose of the present pilot study was to provide a preliminary estimate of the minimum detectable difference (MDD) and minimum clinically important difference (MCID) of the six-minute walk test (6MWT) and daily activity in outpatients with chronic heart failure (CHF).

METHODS

A convenience sample of 22 adults with stable New York Heart Association Functional Class II and III CHF performed two baseline 6MWTs separated by 30 minutes of rest. Subjects then wore a triaxial accelerometer for 7 days to monitor daily activity. After 7 weeks of usual care, subjects again wore the accelerometer for 7 days and then returned to the clinic to complete the Global Rating of Change Scale (GRS) with regard to their heart disease and perform another set of 6MWTs. For the 6MWT, the MDD was calculated using the two baseline 6MWT distances. For daily activity, the MDD was calculated using two methods: (1) day-to-day test-retest reliability during baseline monitoring, and (2) baseline to follow-up test-retest reliability in those who reported no change on the GRS. The MCID for the 6MWT and daily activity was calculated using the mean and 95% confidence interval (CI95%) for those subjects who reported 'improvement' on the GRS.

RESULTS

The MDD at the CI95% for the 6MWT was 32.4 meters. The MCID for the 6MWT was 30.1 (CI95% 20.8, 39.4) meters. The MDD for daily activity was 5,909 vector magnitude units (VMU·hr.(-1)) The MCID for daily activity was 1,337 VMU·hr.(-1) There was good alignment of the MDD and MCID for the 6MWT, suggesting that clinically meaningful change is approximately 32 meters. However, the calculated MCID was substantially less than measurement error as represented by the MDD, indicating that the MCID was underestimated in this sample or that daily activity may be robust to change in overall disease status.

Cumulative knee adductor load distinguishes between healthy and osteoarthritic knees--a proof of principle study

Cumulative knee adductor load reflects repetitive exposures to medial knee loading that are encountered during daily activity. The purpose of this proof of principle study was to investigate whether cumulative knee adductor load distinguished between adults with and without knee osteoarthritis (OA). Thirty-one adults with radiographic knee OA (53.2±6.1 years old) and 30 healthy adults (33.5±8.0 years old) participated. A non-normalized knee adduction moment waveform was calculated from gait data collected using a motion analysis system with synchronized force plate. The peak and impulse from knee adduction moment was calculated. Cumulative knee adductor load was the product of the knee adduction moment impulse during stance and the mean number of steps taken per day, measured with a uni-dimensional accelerometer. One thousand bootstrap t-tests determined whether cumulative knee adductor load was at least as good as the peak knee adduction moment in discriminating between the healthy and OA groups. Cumulative knee adductor load was nearly two times larger in the knee OA compared to the healthy group (p=0.001). Cumulative knee adductor load was better than the peak knee adduction moment at discriminating between groups (p=0.04). This work provides evidence of validity for cumulative knee adductor load. In the calculation of cumulative loads, non-normalization of the adduction moment impulse to magnitude or time emphasized the importance of the total loads borne through the medial knee compartment during each step.

Lifestyle and high density lipoprotein cholesterol in postmenopause

OBJECTIVES

Menopause is characterized by hormonal and metabolic changes. These are linked to increased risk of cardiovascular disease, for which low blood plasma levels of high density lipoprotein (HDL) cholesterol are an independent risk factor. The present study investigated variables linked with basal plasma HDL cholesterol levels and the effects of aerobic training, on their variations, in 40 postmenopausal women.

METHODS

We assessed body composition, dietary habits and maximal aerobic capacity of participants. Characteristics of daily physical activity and plasma lipoproteins were measured. The women walked on 4 days/week, for 14 weeks, at moderate intensity, and they were grouped according to the resulting tertiles of basal plasma HDL cholesterol levels.

RESULTS

Logistic regression analysis showed that waist-to-hip ratio and number of daily bouts of moderate-intensity physical activity, held for at least 10 consecutive minutes (B10m/day), are predictive variables of basal plasma HDL cholesterol levels. After the training period, the first and second tertiles increased plasma HDL cholesterol levels, while the third tertile decreased plasma HDL cholesterol levels. The tertiles showed different remodelling of spontaneous physical activity: the third tertile reduced B10m/day, while the others did not.

CONCLUSIONS

This study provides knowledge about the relationships of plasma HDL cholesterol levels with characteristics of physical activity. Furthermore, it shows that physical exercise engagement can result in negative compensation of spontaneous physical activity that could counteract or reduce the positive effects of the aerobic training on plasma HDL cholesterol levels.

Muscle activity and inactivity periods during normal daily life

Recent findings suggest that not only the lack of physical activity, but also prolonged times of sedentary behaviour where major locomotor muscles are inactive, significantly increase the risk of chronic diseases. The purpose of this study was to provide details of quadriceps and hamstring muscle inactivity and activity during normal daily life of ordinary people. Eighty-four volunteers (44 females, 40 males, 44.1±17.3 years, 172.3±6.1 cm, 70.1±10.2 kg) were measured during normal daily life using shorts measuring muscle electromyographic (EMG) activity (recording time 11.3±2.0 hours). EMG was normalized to isometric MVC (EMG_MVC) during knee flexion and extension, and inactivity threshold of each muscle group was defined as 90% of EMG activity during standing (2.5±1.7% of EMG_MVC). During normal daily life the average EMG amplitude was 4.0±2.6% and average activity burst amplitude was 5.8±3.4% of EMG_MVC (mean duration of 1.4±1.4 s) which is below the EMG level required for walking (5 km/h corresponding to EMG level of about 10% of EMG_MVC). Using the proposed individual inactivity threshold, thigh muscles were inactive 67.5±11.9% of the total recording time and the longest inactivity periods lasted for 13.9±7.3 min (2.5–38.3 min). Women had more activity bursts and spent more time at intensities above 40% EMG_MVC than men (p<0.05). In conclusion, during normal daily life the locomotor muscles are inactive about 7.5 hours, and only a small fraction of muscle's maximal voluntary activation capacity is used averaging only 4% of the maximal recruitment of the thigh muscles. Some daily non-exercise activities such as stair climbing produce much higher muscle activity levels than brisk walking, and replacing sitting by standing can considerably increase cumulative daily muscle activity.

Impact of an Online Healthful Eating and Physical Activity Program for College Students

Purpose.

To identify impact of an online nutrition and physical activity program for college students.

Design.

Randomized, controlled trial using online questionnaires and on-site physical and fitness assessments with measurement intervals of 0 (baseline), 3 (postintervention), and 15 months (follow-up).

Setting.

Online intervention delivered to college students; a centralized Web site was used for recruitment, data collection, data management, and intervention delivery.

Subjects.

College students (18–24 years old, n = 1689), from eight universities (Michigan State University, South Dakota State University, Syracuse University, The Pennsylvania State University, Tuskegee University, University of Rhode Island, University of Maine, and University of Wisconsin).

Intervention.

A 10-lesson curriculum focusing on healthful eating and physical activity, stressing nondieting principles such as size acceptance and eating competence (software developer: Rainstorm, Inc, Orono, Maine).

Measures.

Measurements included anthropometrics, cardiorespiratory fitness, fruit/vegetable (FV) intake, eating competence, physical activity, and psychosocial stress.

Analysis.

Repeated measures analysis of variance for outcome variables.

Results.

Most subjects were white, undergraduate females (63%), with 25% either overweight or obese. Treatment group completion rate for the curriculum was 84%. Over 15 months, the treatment group had significantly higher FV intake (+.5 cups/d) and physical activity participation (+270 metabolic equivalent minutes per week) than controls. For both groups, anthropometric values and stress increased, and fitness levels decreased. Gender differences were present for most variables. First-year males and females gained more weight than participants in other school years.

Conclusion.

A 10-week online nutrition and physical activity intervention to encourage competence in making healthful food and eating decisions had a positive, lasting effect on FV intake and maintained baseline levels of physical activity in a population that otherwise experiences significant declines in these healthful behaviors.

Regulating explosive resistance training intensity using the rating of perceived exertion

Explosive resistance training (ERT) improves older adults' strength and power, and methods to make this form of training more accessible and useful to older adults are needed. The purpose of this study was to evaluate whether the rating of perceived exertion (RPE) scale would predict a broad range of ERT intensities on the leg press with older adults. If successful, then a load-RPE relationship could be used to regulate the intensity of training loads for ERT with older adults, allowing the elimination of maximal strength testing. Twenty-one older adults (≥65 years) with resistance training experience took part in 2 testing sessions. Session 1: Subjects performed high-velocity repetitions on the leg press for up to 9 loads (from 60 to 140% body weight) presented in quasi-randomized order, and then reported their RPE for each load. Session 2: A 1 repetition maximum (1RM) strength test was conducted. Regression analysis revealed that the average RPE across subjects for each load strongly predicted the average %1RM across subjects (R2 = 99.5%; p < 0.001). This allows the establishment of a load-RPE relationship for use in selecting ERT loads for older adults on the leg press. For example, high-intensity loads (70-90% 1RM) that would elicit both strength and power gains when used with ERT aligned with an RPE of 14-16. Lighter loads that may be useful for training for power, but not strength (<70% 1RM), were identified with RPE scores of 13 and lower. The load-RPE relationship may simplify the regulation of intensity of ERT with older adults on the leg press, where the exercising older adult could be guided to select loads according to their RPE.

Validity of a short questionnaire to assess physical activity in 10 European countries

To accurately examine associations of physical activity (PA) with disease outcomes, a valid method of assessing free-living activity is required. We examined the validity of a brief PA questionnaire (PAQ) used in the European Prospective Investigation into Cancer and Nutrition (EPIC). PA energy expenditure (PAEE) and time spent in moderate and vigorous physical activity (MVPA) was measured in 1,941 healthy individuals from 10 European countries using individually-calibrated combined heart-rate and movement sensing. Participants also completed the short EPIC-PAQ, which refers to past year's activity. Pearson (r) and Spearman (σ) correlation coefficients were calculated for each country, and random effects meta-analysis was used to calculate the combined correlation across countries to estimate the validity of two previously- and one newly-derived ordered, categorical PA indices ("Cambridge index", "total PA index", and "recreational index") that categorized individuals as inactive, moderately inactive, moderately active, or active. The strongest associations with PAEE and MVPA were observed for the Cambridge index (r = 0.33 and r = 0.25, respectively). No significant heterogeneity by country was observed for this index (I(2) = 36.3%, P = 0.12; I(2) = 0.0%, P = 0.85), whereas heterogeneity was suggested for other indices (I(2) > 48%, P < 0.05, I(2) > 47%, P < 0.05). PAEE increased linearly across self-reported PA categories (P for trend <0.001), with an average difference of approximately 460 kJ/d for men and 365 kJ/d for women, between categories of the Cambridge index. The EPIC-PAQ is suitable for categorizing European men and women into four distinct categories of overall physical activity. The difference in PAEE between categories may be useful when estimating effect sizes from observational research.