Effect Modification of Cardiorespiratory Fitness, Obesity, and Physical Activity in Adults.

We investigated if cardiorespiratory fitness modifies the association between obesity and the level of physical activity. In this cross-sectional study, we analyzed data from 746 adults, free of diagnosed cardiorespiratory or locomotor diseases. We analyzed sociodemographic and clinical information, cardiovascular risk factors, cardiorespiratory fitness, anthropometry, and level of physical activity (time spent in moderate-to-vigorous physical activity). Those that spent more time in moderate-to-vigorous physical activity were younger, male, with lower body mass index, without self-reported arterial blood hypertension, diabetes and dyslipidemia, non-smokers, and presented with better cardiorespiratory fitness. The linear regression coefficients showed that cardiorespiratory fitness changes according to the level of physical activity and body mass index (obesity in low cardiorespiratory fitness: ß 6.0, p=0.213, 95%CI-3.5 to 15.6; in intermediate cardiorespiratory fitness: ß 6.3, p=0.114, 95%CI-1.5 to 14.2; in high cardiorespiratory fitness: ß-6.3, p=0.304, 95%CI-18.4 to 5.8). This effect modification trend was present after adjusting the model by covariates. Cardiorespiratory fitness potentially modifies the association between body mass index and the level of physical activity. It should be routinely assessed to identify persons with overweight/ obesity with low/ intermediate cardiorespiratory fitness to prescribe individualized training.

Mediator Effect of Cardiorespiratory Fitness on the Association between Physical Activity and Lung Function in Adults: Cross-Sectional Results from the Epimov Study.

We investigated whether cardiorespiratory fitness (CRF) mediates the association between moderate-to-vigorous physical activity (MVPA) and lung function in asymptomatic adults. We examined the cross-sectional results of 1362 adults aged 18-80 years from the Epidemiology and Human Movement Study. Participants were submitted to spirometry to obtain forced vital capacity (FVC) and forced expiratory volume in 1s (FEV1). Additionally, we used cardiopulmonary exercise testing to obtain peak oxygen uptake (V˙O2) as a measure of CRF. Participants used a triaxial accelerometer for 4-7 days to obtain MVPA. Mediation analyses were performed considering the CRF as a mediator, MVPA as an independent variable, and FVC and FEV1 as dependent variables with adjustment for age, sex, and cardiovascular risk score. We aimed to investigate the total (path c) and direct (paths a, b, c') effects through the regression coefficients. We also examined the indirect effect, which was obtained from the product of the coefficients (path ab). Our sample was composed mainly of overweight and middle-aged women. MVPA was positively related to CRF (path a), as well as CRF and lung function (path b). MVPA also presented a significant positive total effect (path c) in the lung function. However, this relationship became non-significant when CRF was included in the model for both FVC and FEV1 (path c'). We did not observe a direct effect of MVPA on the lung function. In contrast, the indirect effect was significant (path ab). Lastly, CRF mediated 60% of the total effect of MVPA on FVC and 61.9% on FEV1. CRF mediates the relationship between lung function and MVPA in asymptomatic adults. Therefore, our results reinforce the need to include CRF assessment in practice clinical routine and suggest that strategies focusing on CRF might be more promising to prevent respiratory diseases in adults.

Early flattening of the oxygen pulse during the cardiopulmonary exercise test in asymptomatic adults and its association with cardiovascular risk factors.

BACKGROUND: Individuals with cardiovascular exercise limitations present oxygen pulse morphology with early flattening (plateau) during the cardiopulmonary exercise test (CPET). Although this oxygen pulse response is well known in cardiac patients, these changes' prevalence and clinical relevance in asymptomatic individuals are not known. We aimed to quantify the proportion of asymptomatic adults with an early flattening of the oxygen pulse and investigate its association with classical cardiovascular risk factors. METHODS: We carried out a cross-sectional study with a sample of 824 adults aged between 18 and 80 years. We assessed anthropometry, body composition, and cardiovascular risk. In addition, we obtained cardiorespiratory and metabolic responses during a ramp protocol treadmill CPET. RESULTS: The prevalence of early flattening of the oxygen pulse was 36.8%. These participants were predominantly females, older, less educated, with a higher body mass and percentage of fat and a lower percentage of lean body mass. After a multinominal multiple logistic regression analysis, we identified female sex (odds ratio, 5.46: 95% confidence interval, 3.73-7.99), low education (2.24: 1.47-3.42), dyslipidemia (1.67: 1.14-2.45), smoking (1.64: 1.00-2.69), and physical inactivity (1.39: 1.02-1.96) as the leading independent predictors of the early flattening of oxygen pulse. CONCLUSION: The early flattening of oxygen pulse is common in asymptomatic adults and is highly determined by modifiable cardiovascular risk factors. These results suggest that identifying the early flattening of oxygen pulse may be helpful in the prevention of cardiovascular diseases.

Unexplained sudden death in patients on the waiting list for renal transplantation.

BACKGROUND: The incidence of unexplained sudden death (SD) and the factors involved in its occurrence in patients with chronic kidney disease are not well known. METHODS: We investigated the incidence and the role of co-morbidities in unexplained SD in 1139 haemodialysis patients on the renal transplant waiting list. RESULTS: Forty-four patients died from SD of undetermined causes (20% of all deaths; 3.9 deaths/1000 patients per year), while 178 died from other causes and 917 survived. SD patients were older and likely to have diabetes, hypertension, past/present cardiovascular disease, higher left ventricular mass index, and lower ejection fraction. Multivariate analysis showed that cardiovascular disease of any type was the only independent predictor of SD (P = 0.0001, HR = 2.13, 95% CI 1.46-3.22). Alterations closely associated with ischaemic heart disease like angina, previous myocardial infarction and altered myocardial scan were not independent predictors of SD. The incidence of unexplained SD in these haemodialysis patients is high and probably a consequence of pre-existing cardiovascular disease. CONCLUSIONS: Factors influencing SD in dialysis patients are not substantially different from factors in the general population. The role played by ischaemic heart disease in this context needs further evaluation.

Effects of Substituting Sedentary Behavior with Light-Intensity or Moderate-to-Vigorous Physical Activity on Obesity Indices in Adults: A Prospective Short-Term Follow-Up Study.

BACKGROUND: Sedentary behavior (SB) is an independent risk factor for cardiovascular diseases. We hypothesized that there may be benefits of replacing SB with light-intensity (LIPA) and moderate-to-vigorous (MVPA) physical activity. Substituting SB with LIPA and MVPA might be associated with body composition changes. METHODS: We assessed body weight, body mass index (BMI), fat body mass (FBM), and physical activity level, as well as one-year changes, in 780 adults (EPIMOV Study). RESULTS: We analyzed into 10-min blocks SB, LIPA, MVPA, and total wear time. After 14 ± 3 months of follow-up, there were 242 completed procedures. We reallocated time spent in SB to LIPA or MVPA and assessed cross-sectional and prospective associations with the outcomes using isotemporal substitution models. In cross-sectional analysis, substituting 10-min blocks of SB with MVPA led to significant decreases of 1.23 kg in body weight, 0.30 kg/m² in BMI, and 0.38% in FBM. 10-min blocks substituting SB with LIPA produced significantly lower body weight (1 kg) and BMI (0.1 kg/m²) values. In longitudinal analysis, reallocating SB to MVPA was only associated with FBM decline (-0.31%). CONCLUSIONS: Substituting SB with MVPA is associated with significant improvement in obesity indices in both cross-sectional and follow-up. Replacing SB with LIPA produced a less consistent impact.

Association between the handgrip strength and the isokinetic muscle function of the elbow and the knee in asymptomatic adults.

BACKGROUND: The handgrip strength is a practical, valid, reliable, low-cost tool that presents strong correlations with several health conditions. However, handgrip strength may be inaccurate to prospectively predict the variability of muscular function since the decrease in muscular strength over the years varies according to a muscular group or between upper and lower limbs. Our hypothesis is that the handgrip strength cannot explain the variance of muscle function prospectively. PURPOSE: The aim of this study was to evaluate the cross-sectional and prospective association between handgrip strength and isokinetic muscle function of the knee and elbow in 780 asymptomatic adults. METHODS: In a sample of 780 adults, we obtained handgrip strength and elbow and knee muscle function (for both flexion and extension at 60°/s and 300°/s) using, respectively, a hydraulic dynamometer and an isokinetic dynamometer. In a cross-sectional analysis, we analyzed the data obtained from baseline assessment. Then, we calculated the absolute change as a result of the variation data between the baseline and the 1-year follow-up assessment of each participant. The correlations were analyzed using Pearson or Spearman coefficients. We used multivariate models to investigate the association between handgrip strength and isokinetic muscle function. RESULTS AND DISCUSSION: The cross-sectional correlations were significantly moderate-to-strong (r = 0.41-0.71, p < 0.01), but became weak-to-moderate (r = 0.26-0.34, p < 0.01) prospectively. In the cross-sectional analysis, the handgrip strength was selected as a strong predictor for isokinetic variables (∆R 2 = 0.171-0.583, p < 0.05) as expected. Although handgrip strength was also selected as a significant predictor in prospective analysis, it explained only a little variance in isokinetic muscle function of the knee (∆R 2 = 0.7-0.117, p < 0.05). Regarding the predictive models for the elbow, handgrip strength was not selected prospectively. CONCLUSION: The 1-year absolute change of the handgrip strength cannot explain the variance of the isokinetic muscle function. Thus, specific measures are required for assessing muscle function in epidemiological studies.

Dynamic physiological responses in obese and non-obese adults submitted to cardiopulmonary exercise test.

PURPOSE: Obese individuals have reduced performance in cardiopulmonary exercise testing (CPET), mainly considering peak values of variables such as oxygen uptake ([Formula: see text]), carbon dioxide production ([Formula: see text]), tidal volume (Vt), minute ventilation ([Formula: see text]) and heart rate (HR). The CPET interpretation and prognostic value can be improved through submaximal ratios analysis of key variables like [Formula: see text], [Formula: see text], [Formula: see text] [Formula: see text] and oxygen uptake efficiency slope (OUES). The obesity influence on these responses has not yet been investigated. Our purpose was to evaluate the influence of adulthood obesity on maximal and submaximal physiological responses during CPET, emphasizing the analysis of submaximal dynamic variables. METHODS: We analyzed 1,594 CPETs of adults (755 obese participants, Body Mass Index ≥ 30 kg/m2) and compared the obtained variables among non-obese (normal weight and overweight) and obese groups (obesity classes I, II and III) through multivariate covariance analyses. RESULT: Obesity influenced the majority of evaluated maximal and submaximal responses with worsened CPET performance. Cardiovascular, metabolic and gas exchange variables were the most influenced by obesity. Other maximal and submaximal responses were altered only in morbidly obese. Only a few cardiovascular and ventilatory variables presented inconsistent results. Additionally, Vtmax, [Formula: see text], Vt/Inspiratory Capacity, Vt/Forced Vital Capacity, Lowest [Formula: see text], [Formula: see text], and the y-intercepts of [Formula: see text] did not significantly differ regardless of obesity. CONCLUSION: Obesity expressively influences the majority of CPET variables. However, the prognostic values of the main ventilatory efficiency responses remain unchanged. These dynamic responses are not dependent on maximum effort and may be useful in detecting incipient ventilatory disorder. Our results present great practical applicability in identifying exercise limitation, regardless of overweight and obesity.

Use of a Smartphone App to Increase Physical Activity Levels in Insufficiently Active Adults: Feasibility Sequential Multiple Assignment Randomized Trial (SMART).

BACKGROUND: The sequential multiple assignment randomized trial (SMART) design allows for changes in the intervention during the trial period. Despite its potential and feasibility for defining the best sequence of interventions, so far, it has not been utilized in a smartphone/gamified intervention for physical activity. OBJECTIVE: We aimed to investigate the feasibility of the SMART design for assessing the effects of a smartphone app intervention to improve physical activity in adults. We also aimed to describe the participants' perception regarding the protocol and the use of the app for physical activity qualitatively. METHODS: We conducted a feasibility 24-week/two-stage SMART in which 18 insufficiently active participants (<10,000 steps/day) were first randomized to group 1 (smartphone app only), group 2 (smartphone app + tailored messages), and a control group (usual routine during the protocol). Participants were motivated to increase their step count by at least 2000 steps/day each week. Based on the 12-week intermediate outcome, responders continued the intervention and nonresponders were rerandomized to subsequent treatment, including a new group 3 (smartphone app + tailored messages + gamification) in which they were instructed to form groups to use several game elements available in the chosen app (Pacer). We considered responders as those with any positive slope in the linear relationship between weeks and steps per day at the end of the first stage of the intervention. We compared the accelerometer-based steps per day before and after the intervention, as well as the slopes of the app-based steps per day between the first and second stages of the intervention. RESULTS: Twelve participants, including five controls, finished the intervention. We identified two responders in group 1. We did not observe relevant changes in the steps per day either throughout the intervention or compared with the control group. However, the rerandomization of five nonresponders led to a change in the slope of the steps per day (median -198 steps/day [IQR -279 to -103] to 20 steps/day [IQR -204 to 145]; P=.08). Finally, in three participants from group 2, we observed an increase in the number of steps per day up to the sixth week, followed by an inflection to baseline values or even lower (ie, a quadratic relationship). The qualitative analysis showed that participants' reports could be classified into the following: (1) difficulty in managing the app and technology or problems with the device, (2) suitable response to the app, and (3) difficulties to achieve the goals. CONCLUSIONS: The SMART design was feasible and changed the behavior of steps per day after rerandomization. Rerandomization should be implemented earlier to take advantage of tailored messages. Additionally, difficulties with technology and realistic and individualized goals should be considered in interventions for physical activity using smartphones. TRIAL REGISTRATION: Brazilian Registry of Clinical Trials RBR-8xtc9c; http://www.ensaiosclinicos.gov.br/rg/RBR-8xtc9c/.

Dose-response relationship between very vigorous physical activity and cardiovascular health assessed by heart rate variability in adults: Cross-sectional results from the EPIMOV study.

The minimum amount of physical activity needed to obtain health benefits has been widely determined. Unlikely, the impact of extreme amounts of very vigorous physical activity (VVPA, ≥ 8 metabolic equivalents) to the heart remains controversial. We aimed to evaluate the dose-response relationship between VVPA and heart rate variability (HRV) in adults. We selected 1040 asymptomatic individuals (60% women, 42 ± 15 years, 28 ± 6 kg/m2) from the Epidemiology and Human Movement Study (EPIMOV). Participants remained in the supine position for 10 min, and we selected an intermediate 5-min window for HRV analysis. The standard deviation of the RR intervals, root mean square of RR intervals, successive RR intervals that differ > 50 ms, powers of the low-and high-frequency bands and Poincaré plot standard deviations were quantified. Participants used a triaxial accelerometer (Actigraph GT3x+) above the dominant hip for 4-7 consecutive days for quantifying their physical activity. We also evaluated the maximum oxygen uptake ([Formula: see text]) during an exercise test. We stratified participants into five groups according to the VVPA in min/week (group 1, ≤ 1.50; 2, 1.51-3.16; 3, 3.17-3.54; 4, 3.55-20.75; and 5, > 20.75). The linear trends of the HRV through the quintiles of VVPA were investigated. We used logarithmic transformations to compare the five groups adjusted for age, sex, cardiovascular risk, and [Formula: see text]. We found a better HRV with increased VVPA for all HRV indices studied (p trend < 0.05). However, group 5 did not differ from group 4 (p > 0.05) for none of the indices. We conclude that there is an incremental benefit of VVPA on HRV of asymptomatic adults. Since we found neither additional benefits nor the harmful impact of amounts of VVPA as high as 22 min/week on HRV, our results should not discourage asymptomatic adults to perform VVPA.

A new equation to predict peak VO2 in obese patients during cardiopulmonary exercise testing.

We aimed to develop an equation to predict peak VO2 in obese subjects undergoing CPET. In addition, we evaluated and compared three published equations. We randomized 346 obese subjects undergoing CPET into a group for developing the equation (n = 272) and a group for cross-validation (n = 74), compared through the Bland and Altman method. Height, sex and age were responsible for 85·5% of total variability of the peak VO2. Additional 1% and 0·7% of the variability were, respectively, explained by physical inactivity and diabetes. The equation devised was as follows: peakVO2mlmin-1=-677·8+(2135·9×heightm)+(706·8×sexmales=1;females=0)-(15·5×ageyears)-(161·1×physicalinactivityyes=1;no=0)-(176·3×diabetesyes=1;no=0). The mean difference between the estimated and measured peak VO2 was 7 ml min-1 , with a 23·9% bias. Published equations overestimated the peak VO2 by 35·3%, 49·1% and 46·2% bias. The equation developed in this study performed better in predicting peak VO2 in obese adults improving ramp protocol design and CRF evaluations in obese subjects.

Living near the port area is associated with physical inactivity and sedentary behavior.

CONTEXT AND OBJECTIVE:: The impact of the port of Santos, Brazil, on the population's health is unknown. We aimed to evaluate the association between living near the port area and physical inactivity and sedentary behavior. DESIGN AND SETTING:: Cross-sectional study developed at a university laboratory and a diagnostic clinic. METHODS:: 553 healthy adults were selected and their level of physical activity in daily life was assessed using accelerometers. Multiple linear and logistic regressions were performed using physical inactivity and sedentary behavior as the outcomes and living near the port area as the main risk factor, with adjustments for the main confounders. RESULTS:: Among all the participants, 15% were resident near the port area. They took 699 steps/day and presented, weekly, 2.4% more sedentary physical activity, 2.0% less time in standing position and 0.9% more time lying down than residents of other regions. Additionally, living near the port area increased the risk of physical inactivity by 2.50 times and the risk of higher amounts of sedentary behavior (≥ 10 hours/day) by 1.32 times. CONCLUSION:: Living near the port of Santos is associated with physical inactivity and higher sedentary behavior among adults, regardless of confounders. The reasons for this association should be investigated in longitudinal studies.

Association between physical activity in daily life and pulmonary function in adult smokers.

OBJECTIVE: To determine whether the level of physical activity in daily life (PADL) is associated with pulmonary function in adult smokers. METHODS: We selected 62 adult smokers from among the participants of an epidemiological study conducted in the city of Santos, Brazil. The subjects underwent forced spirometry for pulmonary function assessment. The level of PADL was assessed by the International Physical Activity Questionnaire and triaxial accelerometry, the device being used for seven days. The minimum level of PADL, in terms of quantity and intensity, was defined as 150 min/week of moderate to vigorous physical activity. Correlations between the studied variables were tested with Pearson's or Spearman's correlation coefficient, depending on the distribution of the variables. We used linear multiple regression in order to analyze the influence of PADL on the spirometric variables. The level of significance was set at 5%. RESULTS: Evaluating all predictors, corrected for confounding factors, and using pulmonary function data as outcome variables, we found no significant associations between physical inactivity, as determined by accelerometry, and spirometric indices. The values for FVC were lower among the participants with arterial hypertension, and FEV1/FVC ratios were lower among those with diabetes mellitus. Obese participants and those with dyslipidemia presented with lower values for FVC and FEV1. CONCLUSIONS: Our results suggest that there is no consistent association between physical inactivity and pulmonary function in adult smokers. Smoking history should be given special attention in COPD prevention strategies, as should cardiovascular and metabolic comorbidities.

Restrictive pattern on spirometry: association with cardiovascular risk and level of physical activity in asymptomatic adults.

OBJECTIVE: To determine whether a restrictive pattern on spirometry is associated with the level of physical activity in daily life (PADL), as well as with cardiovascular disease (CVD) risk factors, in asymptomatic adults. METHODS: A total of 374 participants (mean age, 41 ± 14 years) underwent spirometry, which included the determination of FVC and FEV1. A restrictive pattern on spirometry was defined as an FEV1/FVC ratio > 0.7 and an FVC < 80% of the predicted value. After conducting demographic, anthropometric, and CVD risk assessments, we evaluated body composition, muscle function, and postural balance, as well as performing cardiopulmonary exercise testing and administering the six-minute walk test. The PADL was quantified with a triaxial accelerometer. RESULTS: A restrictive pattern on spirometry was found in 10% of the subjects. After multivariate logistic regression, adjusted for confounders (PADL and cardiorespiratory fitness), the following variables retained significance (OR; 95% CI) as predictors of a restrictive pattern: systemic arterial hypertension (17.5; 1.65-184.8), smoking (11.6; 1.56-87.5), physical inactivity (8.1; 1.43-46.4), larger center-of-pressure area while standing on a force platform (1.34; 1.05-1.71); and dyslipidemia (1.89; 1.12-1.98). CONCLUSIONS: A restrictive pattern on spirometry appears to be common in asymptomatic adults. We found that CVD risk factors, especially systemic arterial hypertension, smoking, and physical inactivity, were directly associated with a restrictive pattern, even when the analysis was adjusted for PADL and cardiorespiratory fitness. Longitudinal studies are needed in order to improve understanding of the etiology of a restrictive pattern as well as to aid in the design of preventive strategies.

Association between obesity and sedentary behavior in adults / Associação entre a obesidade e o comportamento sedentário em adultos

Abstract Although sedentary behavior (SB) is related to the development of metabolic diseases, there is still no consensus in literature about the association between accelerometer-based SB and obesity, especially adjusted for cardiovascular risk factors and level of daily physical activities. The aim was to evaluate the association between obesity and SB adjusted for potential confounders in adults. Data from 780 participants of the Epidemiology and Human Movement (EPIMOV) Study were analyzed. Body weight, body mass index (BMI), and fat body mass as percentage (%FBM) (bioelectrical impedance) were obtained and, then, used to stratify participants. SB was objectively measured using triaxial waist-worn accelerometers placed above the dominant hip during waking hours for at least four consecutive days (4-7 days). SB and its pattern were not significantly different between obesity groups. Although SB presented some significant correlations with obesity, the correlation and determination coefficient indicated weak association between SB and obesity (e.g., BMI and %FBM). Obesity presented little or no association with SB and its pattern after adjustment for potential confounders, especially when SB is measured through accelerometry.

Resumo Embora o comportamento sedentário (CS) esteja relacionado ao desenvolvimento de doenças metabólicas, ainda não há consenso na literatura sobre a associação entre o CS avaliado diretamente por acelerometria e a obesidade, especialmente quando essa relação é ajustada por fatores de risco cardiovascular e nível de atividade física. Objetivou-se avaliar a associação entre CS e obesidade ajustada por potenciais confundidores em adultos. Foram analisados os dados de 780 participantes do Estudo Epidemiológico sobre o Movimento Humano (EPIMOV). Dados relativos à massa corporal, índice de massa corporal (IMC) e porcentagem de gordura corporal (%GC) (bioimpedância elétrica) foram obtidos e, então, utilizados para estratificar os participantes. O CS foi medido objetivamente por meio de acelerômetros triaxiais colocados sob o quadril dominante durante as horas de vigília por, pelo menos, quatro dias consecutivos (4-7 dias). O CS e seu padrão não foram significativamente diferentes entre os grupos de obesidade. Embora o CS tenha apresentado algumas correlações significativas com a obesidade, o coeficiente de correlação e determinação indicou uma fraca associação entre o CS e a obesidade (por exemplo, IMC e %GC). A obesidade apresentou pouca ou nenhuma associação com o CS e seu padrão após o ajuste para potenciais fatores de confusão, principalmente quando avaliado com acelerômetro.

Screening for physical inactivity among adults: the value of distance walked in the six-minute walk test. A cross-sectional diagnostic study.

CONTEXT AND OBJECTIVES: Accelerometry provides objective measurement of physical activity levels, but is unfeasible in clinical practice. Thus, we aimed to identify physical fitness tests capable of predicting physical inactivity among adults. DESIGN AND SETTING: Diagnostic test study developed at a university laboratory and a diagnostic clinic. METHODS: 188 asymptomatic subjects underwent assessment of physical activity levels through accelerometry, ergospirometry on treadmill, body composition from bioelectrical impedance, isokinetic muscle function, postural balance on a force platform and six-minute walk test. We conducted descriptive analysis and multiple logistic regression including age, sex, oxygen uptake, body fat, center of pressure, quadriceps peak torque, distance covered in six-minute walk test and steps/day in the model, as predictors of physical inactivity. We also determined sensitivity (S), specificity (Sp) and area under the curve of the main predictors by means of receiver operating characteristic curves. RESULTS: The prevalence of physical inactivity was 14%. The mean number of steps/day (≤ 5357) was the best predictor of physical inactivity (S = 99%; Sp = 82%). The best physical fitness test was a distance in the six-minute walk test and ≤ 96% of predicted values (S = 70%; Sp = 80%). Body fat > 25% was also significant (S = 83%; Sp = 51%). After logistic regression, steps/day and distance in the six-minute walk test remained predictors of physical inactivity. CONCLUSION: The six-minute walk test should be included in epidemiological studies as a simple and cheap tool for screening for physical inactivity.

Effects of obesity on postural balance and occurrence of falls in asymptomatic adults / Efeitos da obesidade no equilíbrio postural e ocorrência de quedas em adultos assintomáticos

Abstract Introduction: Previous studies suggested that body weight is a strong predictor for postural balance. High body mass index (BMI) presented an association with increased postural sway. However, it seems controversial since studies reported no difference between obese and control group regarding the position of the center of pressure in static postural balance (PB). Also, there is a lack of investigations about the impact of obesity on PB, free of the confound effect of cardiometabolic risk. Objective: The aim of this study was to evaluate the effects of obesity in static PB and occurrence of falls in asymptomatic adults and older adults over 40 years old. Method: The PB of 624 subjects divided into quartiles for BMI, waist-to-hip ratio, waist-to-height and fat body mass as percentage (%FBM) was assessed with and without vision using a force platform. An MANOVA was used to determine if there were differences between quartiles and a logistic regression analysis adjusted for confounders variables were applied to determine the obesity role in the occurrence of falls. Results: We found weak to moderate bivariate correlations between obesity and static PB, which became non-significant after adjustment. We found significant differences between first and fourth quartiles, especially using %FBM. Obesity was not related to the occurrence of falls since the odds ratio values became non-significant for all the indices of obesity after adjustment. Conclusion: Obesity presents little influence on maintaining static PB and seems not to determine the occurrence of falls among subjects over 40 years old.

Resumo Introdução: Estudos prévios sugerem que o peso corporal é forte preditor do equilíbrio postural. Índice de Massa Corporal (IMC) apresenta associação com oscilação corporal aumentada. Contudo, isto é controverso já que estudos reportaram que não há diferença entre obesos e grupo controle em relação ao deslocamento do centro de pressão no equilíbrio postural (EP) estático. Além disso, a literatura é escassa sobre o impacto da obesidade sem o efeito confundidor do risco cardiometabólico. Objetivo: Avaliar os efeitos da obesidade no EP estático e na ocorrência de quedas em adultos assintomáticos acima de 40 anos. Método: O EP estático dos 624 indivíduos divididos segundo os quartis de IMC, relação cintura-quadril e cintura-altura e gordura corporal em porcentagem (% GC) foi avaliado com olhos abertos e fechados usando uma plataforma de força. As diferenças entre os quartis foram determinadas por meio de uma MANOVA e o papel da obesidade na ocorrência de quedas foi analisado por meio de regressão logística ajustada pelos principais confundidores. Resultados: Obtivemos correlações bivariadas fracas a moderadas entre a obesidade e o EP estático, que, após ajuste, não foram estatisticamente significativas. Observamos diferenças significativas entre primeiro e quarto quartis, sobretudo para quartis de %GC. A obesidade não se associou à ocorrência de quedas já que os valores de odds ratio perderam significância para todos os índices d e obesidade após o ajuste pelos confundidores. Conclusão: Obesidade apresenta pouca ou nenhuma influência na manutenção do EP estático e parece não determinar a ocorrência de quedas em indivíduos acima de 40 anos.

Reference values for the 6-min walk test in healthy middle-aged and older adults: from the total distance traveled to physiological responses / Valores de referência para o teste de caminhada de 6 minutos em adultos saudáveis de meia-idade e idosos: da distância total percorrida às respostas fisiológicas / Valores de referencia para la prueba de caminata de 6 minutos en adultos sanos de mediana edad y de edad avanzada: de la distancia total a las respuestas fisiológicas

Abstract Introduction: Physiological responses to the 6-min walk test (6MWT) have been increasingly evaluated in patients with cardiopulmonary diseases. However, previous studies did not include healthy persons. Objective: To evaluate the intensity of 6MWT, to develop a series of predictive equations for the physiological variables and to test their reliability in healthy middle-aged and older adults. Method: We evaluated 102 non-trained healthy adults (54 women, aged 61 ± 10 years) and a cross-validation sample of 30 participants. We measured physiological responses to the 6MWT and a cardiopulmonary exercise testing (CPET) on a treadmill. Results: The R2 values for regression analysis adjusted by age, body mass, stature, and sex ranged from 0.25 for heart rate and 0.46 for peak V ˙ O 2 The 6MWT distance and 6MWT peak V ˙ O 2 represented 110 ± 10% and 102 ± 15% of the predicted values, respectively, using our equations. The intensity of 6MWT corresponded to 72 ± 13% of the peak O2 and 78 ± 23% of the peak HR in the CPET. Peak V ˙ O 2 in the CPET was adequately predicted by 6MWT peak V ˙ O 2 (R2 = 0.76) and 6MWD (R2 = 0.54). Conclusion: The 6MWT represents a moderate to high-intensity test in middle-aged and older healthy adults and is valid for assessing maximal aerobic exercise capacity. Physiological responses to the 6MWT may be adequately predicted with a combination of anthropometrics and demographics.

Resumo Introdução: As respostas fisiológicas ao teste de caminhada de 6 minutos (TC6) têm sido cada vez mais avaliadas em pacientes com doenças cardiopulmonares. No entanto, estudos anteriores não incluíram pessoas saudáveis. Objetivo: Avaliar a intensidade do TC6, desenvolver uma série de equações preditivas para as variáveis fisiológicas e testar sua confiabilidade em indivíduos saudáveis de meia-idade e idosos. Método: Avaliamos 102 adultos saudáveis não treinados (54 mulheres, com idade de 61 ± 10 anos) e uma amostra de validação cruzada de 30 participantes. Nós medimos as respostas fisiológicas ao TC6 e ao teste de exercício cardiopulmonar (TECP) em esteira rolante. Resultados: Os valores de R2 para análise de regressão ajustados por idade, massa corporal, estatura e sexo variaram de 0,25 para frequência cardíaca e 0,46 para pico V ˙ O 2 A distância e o V ˙ O 2 no TC6 representou 110 ± 10% e 102 ± 15% dos valores previstos, respectivamente, usando nossas equações. A intensidade do TC6 correspondeu a 72 ± 13% do pico de V ˙ O 2 e 78 ± 23% do pico de frequência cardíaca no TECP. O pico de no TECP foi adequadamente previsto pelo pico de V ˙ O 2 (R2 = 0,76) e pela distância no TC6 (R2 = 0,54). Conclusão: O TC6 representa um teste de intensidade moderada a alta em adultos saudáveis de meia-idade e idosos e é válido para avaliar a capacidade máxima de exercício aeróbico. Respostas fisiológicas ao TC6 podem ser adequadamente previstas com uma combinação de dados antropométricos e demográficos.

Resumen Introducción: Las respuestas fisiológicas a la prueba de caminata de 6 minutos (PC6M) se han evaluado cada vez más en pacientes con enfermedades cardiopulmonares. Sin embargo, estudios anteriores no incluyeron a personas sanas. Objetivo: Evaluar la intensidad de la PC6M, desarrollar una serie de ecuaciones predictivas para las variables fisiológicas y probar su confiabilidad en individuos sanos de mediana edad y en ancianos. Método: Evaluamos 102 adultos sanos no entrenados (54 mujeres, con edad de 61 ± 10 años) y una muestra de validación cruzada de 30 participantes. Medimos las respuestas fisiológicas a la PC6M y a una prueba de ejercicio cardiopulmonar (PECP) en la cinta de correr. Resultados: Los valores de R2 para análisis de regresión ajustados por edad, masa corporal, estatura y sexo variaron de 0,25 para frecuencia cardíaca y 0,46 para pico O2. La distancia y el V ˙ O 2 en la PC6M representaron 110 ± 10% y 102 ± 15% de los valores previstos, respectivamente, usando nuestras ecuaciones. La intensidad de la PC6M correspondió a 72 ± 13% del pico de V ˙ O 2 y a 78 ± 23% del pico de frecuencia cardiaca en la PECP. El pico de V ˙ O 2 en la PECP fue adecuadamente previsto por el pico de V ˙ O 2 (R2 = 0,76) y por la distancia en la PC6M (R2 = 0,54). Conclusión: La PC6M representa una prueba de intensidad moderada a alta en adultos sanos de mediana edad y en ancianos y es válida para evaluar la capacidad máxima de ejercicio aeróbico. Las respuestas fisiológicas a la PC6M pueden ser previstas con una combinación de datos antropométricos y demográficos.

The association between physical activity, sedentary behavior and the occurrence of falls in asymptomatic adults over 40 years old / Associação entre atividade física, comportamento sedentário e a ocorrência de quedas em adultos assintomáticos acima dos 40 anos de idade / La asociación entre la actividad física, el comportamiento sedentario y la ocurrencia de caídas en adultos asintomáticos mayores de 40 años

Abstract Introduction: Sedentary behavior (SB) has been described as an independent risk factor for health, regardless of the recommended amount of moderate-to-vigorous physical activity (MVPA). However, SB and MVPA as predictors of falls have been poorly investigated. Objective: To compare the associations between SB and MVPA and the occurrence of falls in middle-aged and older adults. Method: The participants wore a triaxial accelerometer over the dominant hip for seven days to measure SB and MVPA. The occurrence of falls and cardiovascular risk factors were assessed by self-report. Isokinetic peak torque (PT) of knee extension, peak oxygen uptake (V'O2) in a ramp treadmill protocol, and lean (LBM) body mass and body fat (BFM) (bioelectrical impedance) were also assessed. The critical roles of SB and MVPA on the occurrence of falls were compared by multiple logistic regression adjusted for age, sex, cardiovascular risk factors, LBM, peak V'O2, and PT of knee extension. Results: 379 participants were evaluated, aged 40-80 years. Forty-eight participants reported at least one fall in the previous 12 months (14.5%). Fallers presented lower SB and higher MVPA. They were predominantly women and older adults with lower physical fitness. After multivariate analysis, MVPA, but not SB, was selected as an independent predictor of falls, increasing the odds ratio of having a fall (1.184, 95% confidence interval, 1.016 - 1.378). Conclusion: Episodes of falls in predominantly middle-aged and women subjects were associated with a higher amount of MVPA, not the opposite, indicating an adverse effect of MVPA in these subjects.

Resumo Introdução: O Comportamento sedentário (CS) tem sido descrito como fator de risco independente para saúde, a despeito da recomendação de atividade física moderada a intensa (AFMI). Contudo, pouco foi investigado se CS e AFMI são preditores da ocorrência de quedas. Objetivo: Comparar as associações entre CS e AFMI e a ocorrência de quedas em adultos de meia-idade e idosos. Método: Os participantes usaram acelerômetro triaxial no quadril dominante por sete dias para obtenção de CS e AFMI. A ocorrência de quedas e o risco cardiovascular foram avaliados através de autorrelato. Avaliamos o pico de torque (PT) isocinético da extensão de joelho, o pico de consumo de oxigênio (V'O2) em protocolo de rampa na esteira, e massa magra (MMC) e gordura (GC) corporais (bioimpedância elétrica). Comparamos o papel de CS e AFMI na ocorrência de quedas através de regressões lineares múltiplas ajustadas por idade, sexo, fatores de risco para doença cardiovascular, MMC, V'O2 pico, e PT da extensão de joelho. Resultados: Avaliamos 379 participantes de 40 - 80 anos. Quarenta e oito participantes reportaram, pelo menos, uma queda nos 12 meses anteriores ao estudo (14.5%). Os caidores apresentaram menor CS e maior AFMI. Eles eram predominantemente mulheres e idosos com menor aptidão física. Após as análises multivariadas, AFMI foi selecionada como preditor independente da ocorrência de quedas, aumentando o odds ratio de cair (1.184, 95% intervalo de confiança, 1.016 - 1.378). Conclusão: Os episódios de quedas, sobretudo em mulheres de meia-idade, foram associados com maior AFMI, indicando efeito adverso da AFMI nestes sujeitos.

Resumen Introducción: El comportamiento sedentario (CS) se ha descrito como un factor de riesgo independiente para la salud, independientemente de la cantidad recomendada de actividad física moderada a vigorosa (AFMV). El CS y el AFMV como predictores de caídas fueron poco investigados. Objetivo: Comparar las asociaciones entre CS y AFMV, y la ocurrencia de caídas en adultos de mediana edad y mayores. Método: Los participantes usaron un acelerómetro triaxial durante siete días para medir CS y AFMV. La ocurrencia de caídas y factores de riesgo cardiovascular se evaluaron mediante autoinforme. Se evaluó el torque máximo isocinético (TM) de la extensión de la rodilla, el consumo máximo de oxígeno (V'O2) en un protocolo de rampa en la estera, y masas corporales magra (MMC) y grasa (GC) (impedancia bioeléctrica). Comparamos los papeles de CS y AFMV en la ocurrencia de caídas mediante la regresión logística múltiple ajustada por edad, sexo, factores de riesgo cardiovascular, MMC, pico de V'O2 y TM de la extensión de la rodilla. Resultados: Se evaluaron 379 participantes de 40 - 80 años. Cuarenta y ocho participantes informaron al menos una caída en los 12 meses previos (14,5%). Caedores presentaron menor CS y mayor AFMV. Eran predominantemente mujeres y mayores con menor aptitud física. Después de los análisis multivariados, AFMV, pero no CS, fue seleccionada como predictor independiente de caídas, lo que aumentó la odds ratio de tener una caída (1.184, intervalo de confianza del 95%, 1,016 - 1,378). Conclusión: los episodios de caídas en mujeres de mediana edad se asociaron con mayor AFMV, lo que indica un efecto adverso de AFMV en estos sujetos.

Prevalence of exercise intolerance in obese adults undergoing cardiopulmonary exercise testing / Prevalência de intolerância ao exercício em adultos obesos submetidos ao teste de exercício cardiopulmonar

Abstract We hypothesized that the prevalence of exercise intolerance (EI, peak O2 uptake < 83%pred.) is not significantly affected by body mass index (BMI) in adults undergoing cardiopulmonary exercise testing (CPET). We aimed to evaluate the prevalence of EI and the influence of BMI in asymptomatic adults. The results of 780 adults (age 41 ± 13 years) who underwent CPET were evaluated. Participants were stratified according to BMI: normal weight (n = 227), overweight (n = 198), and obese class 1 (n = 155), 2 (n = 131), and 3 (n = 69). After cardiovascular risk assessment, the participants underwent CPET on a treadmill ramp protocol. The prevalence of EI was 20, 16, 21, 25, and 21% in the stratified groups respectively, and no significant differences were found. Predictors of EI were physical inactivity, age, and smoking. The prevalence of EI in asymptomatic adults is considerable, regardless of BMI. The obesity-related reduction in cardiorespiratory fitness seems to be as clinically relevant as in non-obese counterparts.

Resumo Levantamos a hipótese de que a prevalência de intolerância ao exercício (IE, pico de consumo de O2 < 83%pred.) não é significativamente afetada pelo índice de massa corporal (IMC) em adultos submetidos ao teste de exercício cardiopulmonar (TECP). Nosso objetivo foi avaliar a prevalência de IE e a influência do IMC em adultos assintomáticos. Foram avaliados os resultados do TECP de 780 adultos (idade 41 ± 13 anos). Os participantes foram estratificados de acordo com o IMC: eutrófico (n = 227), sobrepeso (n = 198), e obesidade grau 1 (n = 155), 2 (n = 131), e 3 (n = 69). Após a avaliação do risco cardiovascular, os participantes foram submetidos ao TECP em uma esteira, sob o protocolo de rampa. A prevalência de IE foi 20, 16, 21, 25, e 21% respectivamente nos grupos estratificados, e nenhuma diferença significativa foi encontrada. Os preditores da IE foi inatividade física, idade e tabagismo. A prevalência de IE em adultos assintomáticos é considerável, independentemente do IMC. A redução da aptidão cardiorrespiratória relacionada a obesidade parece ser clinicamente relevante como em não obesos.

Living near the port area is associated with physical inactivity and sedentary behavior / Morar perto da área portuária está associado à inatividade física e comportamento sedentário

ABSTRACT CONTEXT AND OBJECTIVE: The impact of the port of Santos, Brazil, on the population’s health is unknown. We aimed to evaluate the association between living near the port area and physical inactivity and sedentary behavior. DESIGN AND SETTING: Cross-sectional study developed at a university laboratory and a diagnostic clinic. METHODS: 553 healthy adults were selected and their level of physical activity in daily life was assessed using accelerometers. Multiple linear and logistic regressions were performed using physical inactivity and sedentary behavior as the outcomes and living near the port area as the main risk factor, with adjustments for the main confounders. RESULTS: Among all the participants, 15% were resident near the port area. They took 699 steps/day and presented, weekly, 2.4% more sedentary physical activity, 2.0% less time in standing position and 0.9% more time lying down than residents of other regions. Additionally, living near the port area increased the risk of physical inactivity by 2.50 times and the risk of higher amounts of sedentary behavior (≥ 10 hours/day) by 1.32 times. CONCLUSION: Living near the port of Santos is associated with physical inactivity and higher sedentary behavior among adults, regardless of confounders. The reasons for this association should be investigated in longitudinal studies.

RESUMO CONTEXTO E OBJETIVOS: O impacto do porto de Santos, no Brasil, sobre a saúde da população é desconhecido. Nosso objetivo foi avaliar a associação entre viver nas proximidades da área portuária e a inatividade física e comportamento sedentário. TIPO DE ESTUDO E LOCAL: Estudo transversal desenvolvido em laboratório universitário e em uma clínica de diagnósticos. MÉTODOS: Foram selecionados 553 adultos saudáveis e seu nível de atividade física na vida diária foi avaliado usando acelerômetros. Foi realizada regressão linear múltipla e logística usando a inatividade física e o comportamento sedentário como desfechos e morar perto da área portuária como o fator de risco principal, ajustando para os principais confundidores. RESULTADOS: Entre todos os participantes, 15% residiam na área portuária. Estes deram 699 passos/dia a menos e apresentaram, por semana, 2,4% da atividade física mais sedentária, 2,0% menos tempo em pé e passaram 0,9% mais tempo deitados do que os residentes das demais regiões. Além disso, morar nas proximidades da área portuária aumentou o risco de inatividade física em 2,5 vezes, assim como o risco de maior comportamento sedentário (≥ 10 horas/dia) em 1,32 vezes. CONCLUSÃO: Morar perto do porto de Santos tem associação com a inatividade física, assim como o aumento do comportamento sedentário em adultos, independentemente de fatores de confusão. As razões para tal associação devem ser investigadas em estudos longitudinais.