Energy expenditure and physical activity patterns in children : applicability of simultaneous methods

Consistently, reports in the literature have identified that a sedentary lifestyle contributes to the progression of a range of chronic degenerative diseases. The measurement of energy expenditure and physical activity pattern in children is a challenge for all professionals interested in paediatric health and from a broader perspective, the public health fraternity charged with considering longer term health consequences of physical inactivity. The primary objective of this thesis was to identify a suitable indirect and objective measurement technique for the assessment of energy expenditure and physical activity pattern in children. The ideal characteristics of such a technique are that it should be reproducible and have been validated against a criterion reference method. To achieve this goal, a series of methodological studies were undertaken (Chapters II and III). This work was essential to increase accuracy during the individualised laboratory calibration process and further minimise prediction errors when analysing data from 7 days of monitoring under free-living conditions in the second part of the study (Chapters IV and V). In the first study to verify the combined effect of body position, apparatus and distraction on children's resting metabolic rate (RMR), experiments were carried out on 14 children aged 8-12 (mean age = 10.1 years ± 1.4). Each participant underwent 2 test sessions, one week apart under three different situations: a) using mouthpiece and nose-clip (MN) or facemask (FM); b) sitting (SEAT) or lying (LY) and c) TV viewing (TV) or no TV viewing. In the first session, following 20 min rest and watching TV, the following protocol was used: LY: 20 min - stabilisation; 10 min using MN and 10 min using FM. Body position was then changed to seated: 20 min stabilisation; 10 min using FM; 10 min using MN. In the second session, FM and MN order was changed and participants did not watch TV. Data were analysed according to the eight combinations among the three studied parameters. Repeated measures ANOVA indicated statistically significant differences for &VO2 (p=0.01) and RMR (p=0.02), with TVMNSEAT showing higher values than TVFMLY. Bland-Altman analysis showed a bias for &VO2, &VCO2, RQ and RMR between TVFMLY and TVMNSEAT of -17.8±14.5 ml.min-1, -8.8±14.5 ml. min-1, 0.03±0.05 and -115.2±101.9 kcal.d-1, respectively. There were no differences in RMR measurements due to body position and apparatus when each variable was isolated. Analyses of distraction in three of four combinations indicated no difference between TV and no TV. In summary, different parameter combinations can result in increased bias and variability and thereby reported differences among children's RMR measurement. The second study dealt with treadmill adaptation and determination of self-selected (SS) walking speed. Assessment of individual and group differences in metabolic energy expenditure using oxygen uptake requires that individuals are comfortable with, and can accommodate to, the equipment being utilised. In this study, a detailed proposal for an adaptation protocol based on the SS was developed. Experiments were carried out on 27 children aged 8-12 (mean age = 10.3±1.2 yr). Results from three treadmill tests following the adaptation protocol showed similar results for step length with no significant differences among tests and lower and no statistically significant variability within- and between-days. Additionally, no statistically significant differences between SS determined over-ground and on a treadmill were verified. These results suggest that SS speed determined over-ground is reproducible on a treadmill and the 10 min familiarisation protocol based on this speed provided sufficient exposure to achieve accommodation to the treadmill. The purpose of the third study was to verify within- and between-day repeatability and variability in children's oxygen uptake ( &VO2), gross economy (GE) [ &VO2 divided by speed] and heart rate (HR) during treadmill walking based on SS. 14 children (mean age = 10.2±1.4 yr) undertook 3 testing sessions over 2 days in which four walking speeds, including SS, were tested. Within- and between-day repeatability was assessed using the Bland and Altman method and coefficients of variability (CV) were determined for each child across exercise bouts and averaged to obtain a mean group CV value for &VO2, GE and HR per speed. Repeated measures ANOVA showed no statistically significant differences in within- or between-day CV for &VO2, GE or HR at any speed. Repeatability within and between-day for &VO2, GE and HR for all speeds was verified. These results suggest that submaximal &V O2 during treadmill walking is stable and reproducible at a range of speeds based on children's SS. In the fourth study, the objective was to establish the effect of walking speed on substrate oxidation during a treadmill protocol based on SS. Experiments were carried out on 12 girls aged 8-12 (mean age = 9.9±1.4 yr). Each participant underwent 2 test sessions, one week apart. Workloads on the treadmill included 2 speeds slower than SS (1.6 [V1] and 0.8 km.h-1 [V2] slower than SS), SS (V3), and a speed 0.8 km.h-1 faster than SS (V4). Indirect calorimetry from respired gas measurements enabled total fat (FO) and carbohydrate (CHO) oxidation rates to be calculated according to the non-protein respiratory quotient (Peronnet and Massicote, 1991) and percentage of CHO and FO calculations using equations from McGilvery and Goldstein (1983). Repeated measures ANOVA followed by a Tukey Post Hoc test (p 50%P &VO2 (P &VO2 = the highest &VO2 observed during an exercise test to exhaustion). Results of the current study compared to observations in the literature showed that HR I 140 bpm consistently estimates lower MVPA time than HR > 50%P &VO2. When these two PA indices were compared with individual and standard MET measured minute-byminute, statistically significant differences were verified among all of them at MPA, but no differences were verified at VPA, except between individual and standard METs. However, whether each one of the PA indices used are under- or overestimating time at MVPA is still debatable due to the lack of a gold standard. Finally, each index used in this study classified different numbers of participants as achieving the PA target of 60 min.d-1. The wide variability between indices when attempting to classify children who are achieving the recommended target is cause for great concern because habitually these indices are utilised as screening tools in paediatric and public health settings and used to guide behavioural interventions

Predição da frequência cardíaca basal de indivíduos com níveis de atividade física alto e baixo

INTRODUCTION: Basal heart rate (HRbasal) is measured minutes upon waking up, since it has rhythmic changes throughout the day. OBJECTIVE: Considering the difficulty in achieving the standard conditions for its measurement, the objective was to propose an equation for predicting HRBasal. Therefore, at first, it was necessary to describe the pattern of rhythmicity of HR and study the influence of habitual physical activity level (PAL) on this rhythmicity. METHOD: 90 subjects (54 men and 36 women) filled out the Baecke Questionnaire, median was used to form the PAL A and PAL B groups. The subjects self-assessed HRres at 6, 9, 12, 15, 18, 21 and 24 h using a cardio frequency meter. To describe the rhythmicity and identify the PAL influence, ANOVA followed by Tukey test (p> 0.05) were applied for absolute and normalized values of HRres. The normalized values were adjusted by second-order polynomial to construct the prediction equation, whose validity was tested by Pearson correlation (p> 0.05) and standard error of estimate (SEE). RESULTS: HRres in bpm, of the PAL A group was lower than in the PAL B group at all moments tested: 60 ± 7.5, 64 ± 9.3, 63 ± 8.1, 66 ± 8.7, 66 ± 7,7, 64 and 60 ± 8.1 ± 8.2 compared to: 66 ± 9.6, 11.4 ± 71, 72 ± 11.6, 73 ± 10.8, 10.7 ± 74, 69 ± 9.4 and 10.7 ± 68. Concerning normalized values, no significant differences were found between the two groups and both showed rhythmicity similar to a parabola. The prediction equation showed r 0.70 to 0.83 and SEE from 4.8 to 6.2 bpm. CONCLUSION: HRres presents lower values in more active individuals, but with the same pattern of rhythmicity. This equation enables prediction of FCbasal from the measurement of HRres taken at different times of day.INTRODUÇÃO: A frequência cardíaca basal (FCbasal) é medida ao despertar, já que apresenta alterações rítmicas ao longo do dia. OBJETIVO: Em vista da dificuldade em conseguir mensurar, o objetivo do estudo foi propor uma equação de predição da FCBasal. Para isto, foi necessário, em primeiro lugar, descrever o padrão de ritmicidade da FC e estudar a influência do nível de atividade física habitual (NAF) sobre tal ritmicidade. MÉTODO: 90 indivíduos responderam o questionário de Baecke, cuja mediana foi usada para a constituição dos grupos NAF A e NAF B. Os sujeitos autoavaliaram a FCrep às 6, 9, 12, 15, 18, 21 e 24 h. Para descrever a ritmicidade e identificar a influência do NAF, aplicou-se ANOVA seguida do teste de Tukey (p > 0,05) aos valores absolutos e normalizados de FCrep. Os valores normalizados foram ajustados por polinômio de segundo grau para construir a equação de predição, cuja validade foi testada por correlação de Pearson (p > 0,05) e erro padrão de estimativa (EPE). RESULTADOS: A FCrep do grupo NAF A foi menor que a do grupo NAF B em todos horários avaliados: 60 ± 7,5, 64 ± 9,3, 63 ± 8,1, 66 ± 8,7, 66 ± 7,7, 64 ± 8,1 e 60 ± 8,2; em comparação com: 66 ± 9,6, 71 ± 11,4, 72 ± 11,6, 73 ± 10,8, 74 ± 10,7, 69 ± 9,4 e 68 ± 10,7. Para os valores normalizados, não foram encontradas diferenças significativas entre os dois grupos, ambos apresentaram padrão de ritmicidade semelhante a uma parábola. A equação de predição apresentou r de 0,70 a 0,83 e EPE de 4,8 a 6,2 bpm. CONCLUSÃO: A FCrep apresenta valores mais baixos em indivíduos mais ativos, porém com o mesmo padrão de ritmicidade. É possível predizer a FCbasal a partir da medição da FCrep feita em diferentes horários do dia

Utilização de Métodos Objetivos na Avaliação da Atividade Física de Trabalhadores Brasileiros: Uma Revisão Sistemática

Introdução: Quantificar o nível de atividade física (AF) na população em idade laboral tem sido necessário, pois o sedentarismo compreende um dos fatores de risco mais importante na sociedade atual. Porém, para sua quantificação existem métodos subjetivos quanto objetivos, que por suas características podem produzir resultados discrepantes. Objetivo: Verificar o uso de métodos objetivos para avaliação da atividade física (AF) de trabalhadores brasileiros. Métodos: Realizou-se uma pesquisa nas bases de dados Lilacs, Scielo e Pubmed, com artigos originais publicados nos últimos 10 anos sobre trabalhadores brasileiros. Foram encontrados 130 trabalhos empregando métodos tanto subjetivos como objetivos, porém foram incluídos somente estudos que utilizaram métodos objetivos. Após verificação dos critérios de inclusão e exclusão, foram selecionados quatro artigos. Resultados: Os estudos apresentaram faixa etária variada e foram conduzidos em duas diferentes regiões do país (Sudeste e Centro Oeste). Como principais achados dos estudos, verificou-se que o número de passos se associa com os fatores de risco cardiovasculares entre trabalhadores e que a atividade desempenhada tem associação com a carga cardiovascular e a variabilidade da frequência cardíaca. Conclusão: Há uma escassez de estudos conduzidos em trabalhadores brasileiros utilizando métodos objetivos, uma vez que a maioria dos estudos utiliza técnicas subjetivas

Evaluation of lifestyle of female adolescents through latent class analysis approach

Lack of regular physical activity, high sedentary behavior and presence of unbalanced alimentary practices are attitudes associated with an inadequate lifestyle among female adolescents.To assess the lifestyle of female adolescents based on measurements of behavioral variables.Cross-sectional study with 405 female adolescents between 14 and 19 years old, resident and attending public schools in Viçosa (state of Minas Gerais). Their lifestyle was analyzed by the Physical Activity Recall, number of steps, screen time (ST), cellphone time (CT), sitting time, food frequency questionnaire (FFQ), and alcohol and tobacco consumption. With multiple correspondence analysis it was possible to observe dispersion and approximation of the variables’ categories. Latent class analysis (LCA) was used for modeling the “lifestyle” variable, having been conducted in the poLCA (Polychromous Variable Latent Class Analysis) package of the R statistical software.The mean age was 15.92 ± 1.27 years. Most of the adolescents were considered physically inactive (78%) and with low number of steps (82.57%); 41.45% reported not performing Moderate to Vigorous Physical Activities (MVPA) adequately. Sedentary behavior was found high when assessing ST (72.90%) and CT (65.31%). It was found the best fitted latent class model for the lifestyle (p-G2 = 0.055, p-χ2 = 0.066) featured three latent classes and one covariate (alcohol): Class 1, ‘Inactive and Sedentary’ (γ = 77.5%); Class 2, ‘Inactive and Non-sedentary lifestyle (γ=16.31%); and Class 3, ‘Active and sedentary’ (γ=6.19%). Female adolescents that had ‘never consumed alcohol’ were 2.26 times as likely (log OR = 0.8174; p = 0.033) to belong to class 3 (Active & Sedentary lifestyle) than to class 1 (Inactive & Sedentary lifestyle).Latent class analysis model with five manifest variable (MVPA, number of steps, ST, sitting time and number of meals) and alcohol consumption like covariate showed itself to be an accurate and objective method in the assessment of female adolescents’ lifestyle. Female adolescents that had ‘never consumed alcohol’ were more as likely to belong to class ‘Active & Sedentary lifestyle’ than to class Inactive & Sedentary lifestyle. An inactive and sedentary lifestyle is coupled to other unhealthy behaviors during adolescence, possibly carrying over into adult life

Effects of different exercise programs and minimal detectable changes in hemoglobin A1c in patients with type 2 diabetes

The incidence of diabetes mellitus is increasing worldwide, resulting in a global epidemic. The most common type, the type 2 diabetes mellitus, constitutes of 90–95 % of the cases and is characterized by the action of and/or impaired insulin secretion. Regular exercise is a recommended strategy in several studies and guidelines for type 2 diabetes control and complications associated with it. Therefore, we evaluated and compared the effects of aerobic and strength exercise programs on the glycemic control in patients with type 2 diabetes. The selected patients were divided into groups which performed moderate strength training (ST) and aerobic training (AT). The study lasted 20 weeks and was divided into two 10 week phases with anthropometric (body mass index, waist, abdomen and hips circumferences, waist/hip ratio) and biochemical (glycemic and lipid profile) assessments at baseline, 10 weeks and 20 weeks. For intra and inter analyses a mixed ANOVA model was used. Individual changes were calculated using the minimum detectable change, based on a 90 % confidence interval. Eleven patients (five men and six women) completed the 20 weeks of training; five from the ST group and six from the AT. No significant changes were observed in any anthropometric variable in either group. Statistically significant differences were found in mean hemoglobin A1c in both groups between baseline (AT: 8.6 ± 2.5; ST: 9.2 ± 1.9) and 10 weeks (AT: 7.2 ± 1.7; ST: 7.9 ± 1.2) (p = 0.03), and baseline (AT: 8.6 ± 2.5; ST: 9.2 ± 1.9) and 20 weeks (AT: 7.5 ± 1.7; ST: 7.4 ± 0.9) (p = 0.01). For the minimal detectable changes, 40 % of the ST and 33 % of AT achieved these changes for hemoglobin A1c. Both aerobic and strength exercises can help the metabolic control in patients with type 2 diabetes, even without significant changes in anthropometry over the 20 weeks of training. However, this period was sufficient to cause changes in hemoglobin A1c values and the estimated average glucose, which are important parameters in controlling diabetes, thus signaling an important consequence of adhering to an exercise routine for type 2 diabetic patients

Measuring skin temperature before, during and after exercise: a comparison of thermocouples and infrared thermography

Measuring skin temperature (TSK) provides important information about the complex thermal control system and could be interesting when carrying out studies about thermoregulation. The most common method to record TSK involves thermocouples at specific locations; however, the use of infrared thermal imaging (IRT) has increased. The two methods use different physical processes to measure TSK, and each has advantages and disadvantages. Therefore, the objective of this study was to compare the mean skin temperature (MTSK) measurements using thermocouples and IRT in three different situations: pre-exercise, exercise and post-exercise. Analysis of the residual scores in Bland-Altman plots showed poor agreement between the MTSK obtained using thermocouples and those using IRT. The averaged error was -0.75 °C during pre-exercise, 1.22 °C during exercise and -1.16 °C during post-exercise, and the reliability between the methods was low in the pre- (ICC = 0.75 [0.12 to 0.93]), during (ICC = 0.49 [-0.80 to 0.85]) and post-exercise (ICC = 0.35 [-1.22 to 0.81] conditions. Thus, there is poor correlation between the values of MTSK measured by thermocouples and IRT pre-exercise, exercise and post-exercise, and low reliability between the two forms of measurement

Comparação entre as Recomendações do American College Sport Medicine para a Realização de Exercício Aeróbico e a Prática Autosselecionada por Mulheres

Introdução: É corriqueira a prática de atividade física (AF) de forma autosselecionada por essas pessoas. Objetivo: Estabelecer os padrões de AF autosselecionado por mulheres durante a caminhada, corrida e trote e verificar se atendem às diretrizes do American College Sports Science (ACSM) para sua prática. Materiais e Métodos: Participaram do estudo 80 mulheres, sendo divididas em quatro grupos etários (G1 = 20-29 anos; G2 = 30-39 anos; G3 = 40-49 anos; G4 = 50-59 anos). Na primeira etapa foram realizados os procedimentos antropométricos. A segunda etapa consistiu em avaliar uma sessão de exercício sob intensidade autosselecionada através de um monitor cardíaco e IPE. Resultados: Ao analisar o escore do índice de percepção de esforço (IPE), foi encontrado que 43,8% da amostra esteve dentro da intensidade “vigorosa” e 26,3% “moderada”, ambas estando dentro das recomendações do ACSM. Em relação ao percentual da FC (%FC) média, todos os grupos estiveram de acordo com as diretrizes. Quanto ao tempo total da sessão e frequência semanal, todos os grupos atingiram as recomendações mínimas. Conclusão: A maioria das avaliadas autosselecionou intensidades dentro do recomendado pelo ACSM, quando analisado a %FC média, IPE, tempo de treino e frequência semanal

Time required to stabilize thermographic images at rest

Thermography for scientific research and practical purposes requires a series of procedures to obtain images that should be standardized; one of the most important is the time required for acclimatization in the controlled environment. Thus, the objective of this study was to identify the appropriate acclimatization time in rest to reach a thermal balance on young people skin. Forty-four subjects participated in the study, 18 men (22.3 ± 3.1 years) and 26 women (21.7 ± 2.5 years). Thermographic images were collected using a thermal imager (Fluke ®), totaling 44 images over a period of 20 minutes. The skin temperature (TSK) was measured at the point of examination which included the 0 minute, 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20. The body regions of interest (ROI) analyzed included the hands, forearms, arms, thighs, legs, chest and abdomen. We used the Friedman test with post hoc Dunn?s in order to establish the time at rest required to obtain a TSK balance and the Mann-Whitney test was used to compare age, BMI, body fat percentage and temperature variations between men and women, considering always a significance level of pmenor que0.05. Results showed that women had significantly higher temperature variations than men (pmenor que0.01) along the time. In men, only the body region of the abdomen obtained a significant variance (pmenor que0.05) on the analyzed period, both in the anterior and posterior part. In women, the anterior abdomen and thighs, and the posterior part of the hands, forearms and abdomen showed significant differences (pmenor que0.05). Based on our results, it can be concluded that the time in rest condition required reaching a TSK balance in young men and women is variable, but for whole body analysis it is recommended at least 10 minutes for both sexes

Reinvenção das ligas acadêmicas em período de pandemia e interrupção das aulas presenciais

Academic Leagues are characterized as organizations formed by non-profit student groups, which develop didactic, scientific, cultural, and social activities with their members, which approach a particular area of health. This article is a descriptive, retrospective, and cross-sectional report, carried out from the experience of an Academic League at a private university in the State of Rio de Janeiro in 2020 describing their experiences obtained through the actions developed in 2020, during the pandemic caused by COVID-19 and the paralysis of classroom classes, virtualization of them and changes in the academic schedule.As Ligas Acadêmicas são caracterizadas como organizações formadas por núcleos estudantis sem fins lucrativos, que desenvolvem com seus membros atividades didáticas, científicas, culturais e sociais, que acercam uma determinada área da saúde. Esse artigo trata-se de um relato descritivo, retrospectivo e transversal, realizado a partir da vivência de uma Liga Acadêmica em uma universidade privada do Estado do Rio de janeiro no ano de 2020 descrevendo suas experiências obtidas através das ações desenvolvidas no ano de 2020, durante a pandemia causada pela COVID-19 e a paralização das aulas presencias, virtualização das mesmas e mudanças no cronograma acadêmico

Quais razões levam jovens universitários da área de saúde a fazerem uso de automedicação?

The aim was to identify the reasons that lead to self-medication in students in the health area, and to catalog the main medications used. This is an integrative literature review that identified articles related to the subject in the Virtual Health Library (VHL) database. They were selected by the descriptors: Self-medication, University and Analgesics, between the periods of 2015 to 2020, in Portuguese, English and Spanish. Incomplete texts, duplicates and theses were used as exclusion criteria. Totaling 10 eligible articles. It resulted from the synthesis of articles ordered by means of tables, in which it was possible to evidence a high prevalence of self-medication among university students, drug classes, and their determinants. In conclusion, there was a need to implement educational actions to clarify the risk related to self-medication.Objetivou-se identificar os motivos que conduzem a automedicação em estudantes na área da saúde, e catalogar os principais medicamentos utilizados. Trata-se de uma revisão integrativa da literatura que identificou na base de dados da Biblioteca Virtual em Saúde (BVS) artigos relacionados a temática. Foram selecionados mediante os descritores: Automedicação, Universidade e Analgésicos, entre os períodos de 2015 a 2020, em Português, Inglês e Espanhol. Foram utilizados como critérios de exclusão textos incompletos, duplicados e teses. Totalizando 10 artigos elegíveis. Resultou-se através da síntese dos artigos ordenados por meio de tabelas, nos quais, foi possível evidenciar alta prevalência da automedicação entre os universitários, as classes medicamentosas, e seus determinantes. Por conclusão, constatou-se a necessidade de implementar ações educacionais para o esclarecimento do risco relacionado a automedicação