Sleep parameters measured by accelerometry: descriptive analyses from the 22-year follow-up of the Pelotas 1993 birth cohort.

OBJECTIVE: To describe the sleep time window (STW), total sleep time (TST), and sleep percent [SP = (TST/STW) × 100] by accelerometry in a population-based young adult cohort in Brazil. METHODS: Cross-sectional analysis with a 22-year sample (N = 2462). Sleep variables were measured using an accelerometer. The devices were worn on the non-dominant wrist for approximately seven days. A raw data analysis using the GGIR package was performed. The following sleep variables were extracted: TST, STW, and SP. Linear regression was used to adjust averages. All analyses were stratified according to sex. A comparison between weekday and weekend averages was also conducted. RESULTS: The means of TST, STW, and SP for men were 5.9 h, 7.1 h, and 83.1%, respectively. For women, the means of TST, STW, and SP were 6.4 h, 7.6 h, and 84.6%, respectively. Women presented a higher means of all outcomes compared to men (p < 0.001). After adjusting for both sexes, white skin color and not working or studying were associated with higher TST. Individuals not working or studying presented higher means of STW and lower sleep SP. Women with children who were less than two years of age presented lower values of three evaluated outcomes. Regarding behavior and health condition variables, obesity was associated with lower STW only for men. Physical activity was associated with higher SP and risk drinking with lower TST and STW only for women. CONCLUSION: Differences between sexes were observed in TST, STW, and SP. In all outcomes women presented a higher means. Socioeconomic variables were associated with both sexes, but having children and behavior/health conditions differed between sexes.

Objectively Measured Physical Activity Reduces the Risk of Mortality among Brazilian Older Adults.

OBJECTIVES: Use of objectively measured physical activity (PA) in older adults to assess relationship between PA and risk of all-causes mortality is scarce. This study evaluated the associations of PA based on accelerometry and a questionnaire with the risk of mortality among older adults from a city in Southern Brazil. DESIGN: A cohort study. SETTING: Urban area of Pelotas, Southern Brazil. PARTICIPANTS: A representative sample of older adults (≥60 y) from Pelotas, enrolled in 2014. MEASUREMENTS: Overall physical activity (mg), light physical activity (LPA), and moderate to vigorous physical activity (MVPA) were estimated by raw accelerometer data. The International Physical Activity Questionnaire estimated leisure time and commuting PA. Hazard ratios (excluding deaths in the first 6 mo) stratified by sex were estimated by Cox regression analysis considering adjustment for confounders. RESULTS: From the 1451 older adults interviewed in 2014, 145 died (10%) after a follow-up of an average 2.6 years. Men and women in the highest tertile of overall PA had on average a 77% and 92% lower risk of mortality than their less active counterparts (95% confidence interval [CI] = .06-.84 and 95% CI = .01-.65, respectively). The highest tertile of LPA was also related to a lower risk of mortality in individuals of both sexes (74% and 91% lower risk among men and women, respectively). MVPA statistically reduced the risk of mortality only among women (hazard ratio [HR] = .30 and HR = .07 in the second and third tertiles). Self-reported leisure-time PA was statistically associated with a lower risk of mortality only among men. Women in the highest tertiles of commuting PA showed a lower risk of mortality than those in the reference group. CONCLUSION: Accelerometry-based PA was associated with a lower risk of mortality among Brazilian older adults. Older individuals should practice any type of PA. J Am Geriatr Soc 68:137-146, 2019.

Association of moderate-to-vigorous physical activity with neck circumference in eight Latin American countries.

BACKGROUND: Physical activity is a cornerstone in the prevention and treatment of obesity. There are relatively few studies that explore the effect of accelerometer-determined moderate-to-vigorous physical activity (MVPA) on neck circumference (NC), most of them confined to single high-income countries. The present study investigated the association of accelerometer-determined MVPA with NC in adolescents and adults from eight Latin American countries, which are mostly upper-middle income countries. METHODS: The sample consisted of 2370 participants (47.8% male) from the Latin American Study of Nutrition and Health, a multicenter cross-sectional nutrition and health surveillance study of a nationally representative sample from eight Latin American countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela). Times (min/day) in MVPA (defined as time accumulated at ≥1952 activity counts/min) was assessed by ActiGraph GT3X+ accelerometer over 7 days. NC for adolescent was categorized as abnormal if circumference was > 34.5 cm for boys and > 31.25 for girls, whereas for adults the cut-off points for abnormal were > 39 cm for men and > 35 cm women. Multilevel logistic models, including country and region as random effects and adjusted for sex, age, socioeconomic level, and educational level, were used to study the association between MVPA and NC. RESULTS: The average time of MVPA was 34.88 min/day, ranging from 31.16 in Venezuela to 40.27 in Chile. Concerning NC, 37.0% of the sample was classified as having elevated NC. Chile was the country with the highest percentage of people with elevated NC (56.9%), and Colombia had the lowest percentage (24.8%). Overall, the MVPA (min/day) was associated with elevated NC (OR = 0.994, CI95% = 0.990-0.998). In Costa Rica and Peru, there were significant associations between MVPA and NC when analyzed by country. CONCLUSIONS: The present study provided evidence of significant associations between MVPA and NC in adolescents and adults from Latin America, independent of sex, age, socioeconomic level, and educational level. This analysis of accelerometry data and NC represents the first examination of these associations in eight Latin America countries. Further research is required to understand the differences between countries in the observed associations. TRIAL REGISTRATION: ClinicalTrials.Gov NCT02226627 . Retrospectively registered on August 27, 2014.

Physical activity and motor competence in childhood / Prática de atividade física e competência motora na infância

ABSTRACT The objectives of this research were to verify the amount and intensity of physical activity performed by children of low socioeconomic level during weekdays and weekends, to assess motor competence indicators and to verify associations between these variables. A total of 176 children aged 3 to 6 years old participated in the study. They wore an accelerometer for seven consecutive days to measure physical activity engagement, while motor competence was measured by means of the Test of Gross Motor Development (TGMD-2). Boys spent more time on total physical activity than girls did (222.5 min x 204 min; p<0.01) on weekdays. For both sexes, daily average time of total physical activity stood above international guidelines on physical activity (≥ 3h of physical activity per day), but there are indicators of delayed motor competence development, especially in object control skills. In conclusion, boys presented higher physical activity engagement indexes compared to girls and had greater motor competence; however, low values for association between physical activity and motor competence suggest that physical activity amount does not necessarily affect motor competence development.

RESUMO Os objetivos desta pesquisa foram verificar a quantidade e intensidade de atividade física praticada por crianças de baixo nível socioeconômico durante dias de semana e finais de semana, avaliar indicadores de competência motora e verificar as associações entre essas variáveis. Participaram do estudo 176 crianças entre 3 e 6 anos. As crianças usaram acelerômetro por sete dias consecutivos para mensurar a prática de atividade física e a competência motora foi mensurada com a utilização do Test of Gross Motor Development (TGMD-2). Os meninos despenderam mais tempo em atividade física total do que meninas (222,5 min xs 204 min; p<0,01) nos dias de semana. Em ambos os sexos, o tempo médio diário de atividade física total ficou acima das diretrizes internacionais de prática de atividade física (≥ 3h de atividade física por dia), porém há indicadores de atraso no desenvolvimento da competência motora, principalmente nas habilidades de controle de objetos. Concluímos que meninos apresentam maiores índices de prática de atividade física do que meninas e possuem maior competência motora, porém, valores reduzidos de associação entre prática de atividade física e competência motora sugerem que a quantidade de atividade física não necessariamente implica no desenvolvimento da competência motora.

Validation of the Hexoskin wearable vest during lying, sitting, standing, and walking activities.

We tested the validity of the Hexoskin wearable vest to monitor heart rate (HR), breathing rate (BR), tidal volume (VT), minute ventilation, and hip motion intensity (HMI) in comparison with laboratory standard devices during lying, sitting, standing, and walking. Twenty healthy young volunteers participated in this study. First, participants walked 6 min on a treadmill at speeds of 1, 3, and 4.5 km/h followed by increasing treadmill grades until 80% of their predicted maximal heart rate. Second, lying, sitting, and standing tasks were performed (5 min each) followed by 6 min of treadmill walking at 80% of their ventilatory threshold. Analysis of each individual's mean values under each resting or exercise condition by the 2 measurement systems revealed low coefficient of variation and high intraclass correlation values for HR, BR, and HMI. The Bland-Altman results from HR, BR, and HMI indicated no deviation of the mean value from zero and relatively small variability about the mean. VT and minute ventilation were provided in arbitrary units by the Hexoskin device; however, relative magnitude of change from Hexoskin closely tracked the laboratory standard method. Hexoskin presented low variability, good agreement, and consistency. The Hexoskin wearable vest was a valid and consistent tool to monitor activities typical of daily living such as different body positions (lying, sitting, and standing) and various walking speeds.

Opportunities for promoting youth physical activity: an examination of youth summer camps.

BACKGROUND: Youth summer camp programs have the potential to provide opportunities for physical activity, but little to no research has been conducted to determine activity levels of campers. This study aimed to examine physical activity occurring in day and resident summer camps and how activity levels differed in these camps based upon demographic characteristics. METHODS: Pedometer data were collected during hours of camp operation from 150 day campers and 114 resident campers between the ages of 8 and 12 years old. Independent t tests were used to compare physical activity by sex, race, and Body Mass Index. RESULTS: Campers at day camps averaged 11,916 steps per camp day, while resident campers averaged 19,699 steps per camp day. Day campers averaged 1586 steps per hour over 7.5 hour days and resident campers averaged 1515 steps per hour over 13 hour days. Male sex, Caucasian race, and normal Body Mass Index were significant correlates of more physical activity. CONCLUSIONS: Youth summer camps demonstrate the potential to provide ample opportunities for physical activity during the summer months. Traditional demographic disparities persisted in camps, but the structure of camp programs should allow for changes to increase physical activity for all participants.

Self-reported and objective physical activity in postgastric bypass surgery, obese and lean adults: association with body composition and cardiorespiratory fitness.

BACKGROUND: This study aimed to 1) describe physical activity (PA) in 15 post gastric bypass surgery (GB), 16 obese (Ob), and 14 lean (L) participants (mean ± se: age = 37.1 ± 1.6, 30.8 ± 1.9, 32.7 ± 2.3 yrs.; BMI = 29.7 ± 1.2, 38.2 ± 0.8, 22.9 ± 0.5 kg/m2, respectively); and 2) test associations between PA, body composition, and cardiorespiratory fitness (VO2max). METHODS: Participants completed a PA questionnaire after wearing accelerometers from 5-7 days. Body composition was determined with DEXA and CT scans, and VO2max with open circuit spirometry. ANOVA was used to detect differences between groups, and linear regressions to evaluate associations between PA (self-reported, accelerometer), body composition, and VO2max. RESULTS: Self-reported moderate to vigorous PA (MVPA) in GB, Ob, and L participants was 497.7 ± 215.9, 988.6 ± 230.8, and 770.7 ± 249.3 min/week, respectively (P = .51); accelerometer MVPA was 185.9 ± 41.7, 132.3 ± 51.1, and 322.2 ± 51.1 min/week, respectively (P = .03); and steps/day were 6647 ± 141, 6603 ± 377, and 9591 ± 377, respectively (P = .03). Ob showed a marginally higher difference between self-report and accelerometer MVPA (P = .06). Accelerometer-MVPA and steps/day were inversely associated with percent fat (r = -0.53, -0.46), and abdominal fat (r = -0.36, -0.40), and directly associated with VO2max (r = .36). CONCLUSIONS: PA was similar between GB and Ob participants, and both were less active than L. Higher MVPA was associated with higher VO2max and lower body fat.

Predictors of validity and reliability of a physical activity record in adolescents.

BACKGROUND: Poor to moderate validity of self-reported physical activity instruments is commonly observed in young people in low- and middle-income countries. However, the reasons for such low validity have not been examined in detail. We tested the validity of a self-administered daily physical activity record in adolescents and assessed if personal characteristics or the convenience level of reporting physical activity modified the validity estimates. METHODS: The study comprised a total of 302 adolescents from an urban and rural area in Ecuador. Validity was evaluated by comparing the record with accelerometer recordings for seven consecutive days. Test-retest reliability was examined by comparing registrations from two records administered three weeks apart. Time spent on sedentary (SED), low (LPA), moderate (MPA) and vigorous (VPA) intensity physical activity was estimated. Bland Altman plots were used to evaluate measurement agreement. We assessed if age, sex, urban or rural setting, anthropometry and convenience of completing the record explained differences in validity estimates using a linear mixed model. RESULTS: Although the record provided higher estimates for SED and VPA and lower estimates for LPA and MPA compared to the accelerometer, it showed an overall fair measurement agreement for validity. There was modest reliability for assessing physical activity in each intensity level. Validity was associated with adolescents' personal characteristics: sex (SED: P=0.007; LPA: P=0.001; VPA: P=0.009) and setting (LPA: P=0.000; MPA: P=0.047). Reliability was associated with the convenience of completing the physical activity record for LPA (low convenience: P=0.014; high convenience: P=0.045). CONCLUSIONS: The physical activity record provided acceptable estimates for reliability and validity on a group level. Sex and setting were associated with validity estimates, whereas convenience to fill out the record was associated with better reliability estimates for LPA. This tendency of improved reliability estimates for adolescents reporting higher convenience merits further consideration.

Objectively measured physical activity in children from a southern Brazilian city: a population-based study.

BACKGROUND: The aim of this study was to assess physical activity (PA) patterns (intensity and prevalence) in children according to demographic, socioeconomic, and familiar characteristics. METHODS: In 2010, a cross-sectional study of 239 children aged 4-11 was conducted, in Pelotas, Southern Brazil. PA was measured by accelerometry and classified in different intensities. Insufficient physical activity was defined as less than 60 min/day of moderate-to-vigorous PA. Descriptive analyses of accelerometry-related variables were presented. Multivariate Poisson regression models were used to estimate the association between physical insufficient PA and covariates. RESULTS: For both sexes, around 65% of the registered time was spent in sedentary activities and less than 20 min/day in vigorous activity. Age and economic status were inversely associated to PA in all categories of PA. Moderate and vigorous activities means were higher in boys than in girls. The prevalence of insufficient PA was 34.5% in girls and 19.5% in boys. CONCLUSIONS: We found important differences in physical activity patterns according to sex and economic status, as well as a significant decline in time spent in moderate-to-vigorous PA with increasing age. Understanding the relationship between these sociodemographic factors is important to tackle low levels of PA.