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.

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.

Preferential use of nonreversed vein grafts in above-knee femoropopliteal bypasses for critical ischemia: midterm outcome.

We evaluated nonreversed vein grafts in above-knee bypasses for chronic critical limb ischemia in a retrospective study with intention-to-treat analysis in patients who underwent above-knee bypass grafting. During a 4-year period, 51 patients (men, 32; women, 19; mean age = 66 years) with 53 critically ischemic lower extremities underwent above-knee femoropopliteal bypass grafting. The follow-up evaluation consisted of clinical examination, assessment of the ankle-brachial systolic blood pressure index, and, whenever necessary, duplex scanning. Three (5.7%) deaths occurred within 30 days, two from myocardial infarction and one from an undetermined cause. The 2-year cumulative success rate was 82.5 +/- 9.6% for primary patency, 84.6 +/- 8.9% for secondary patency, 90.1 +/- 7.3% for tertiary patency, 86.9 +/- 7.6% for limb salvage, 77.7 +/- 8.4% for survival, 68.0 +/- 11.1% for composite patency, and 68.4 +/- 9.3% for amputation-free survival; the corresponding estimates for vein grafts alone were 86.6 +/- 9.2%, 88.9 +/- 8.6%, 89.0 +/- 8.5%, 88.1 +/- 8.1%, 81.1 +/- 9.1, 76.8 +/- 11.1%, and 72.6 +/- 10.2%. Three prosthetic grafts failed and were replaced with an arm vein graft. Nonreversed vein bypass grafts in above-knee revascularization of critically ischemic limbs are justified.

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.

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.

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.

High sedentary behavior and compromised physical capabilities in adult smokers despite the suitable level of physical activity in daily life / Comportamento sedentário alto e comprometimento da aptidão física em tabagistas adultos apesar do nível adequado de atividade física na vida diária

Abstract Sedentary behavior may play an important role for health outcomes, regardless of the amount of physical activity in daily life (PADL).We aimed to evaluate and compare sedentary behavior as well as physical capabilities in physically active smokers and non-smokers. Twenty-eight adult smokers and 38 non-smokers free of lung disease were matched for age, sex, body mass index, body composition, cardiovascular risk and moderate-to-vigorous PADL. Participants underwent spirometry, cardiopulmonary exercise test (CPET), six-minute walk test (6MWT), isokinetic dynamometry, and body composition (bioelectrical impedance).Despite the similar amount of moderate-to-vigorous PADL(median, 4.5h/week for smokers and 4.0h/week for non-smokers), smokers spent more time lying (median, 8.2h/week: 95% confidence interval, 5.4 to 19.1 vs. 6.1h/week: 3.7 to 11.2) and in sedentary activities (median, 100h/week: 66 to 129 vs. 78h/week: 55 to 122) compared to non-smokers. Smokers also presented worse spirometry, peak V’O2 and maximum heart rate in the CPET, 6MWT, and isokinetic indices (p<0.05). We observed a strong correlation between the time spent lying and spirometry (r = - 0.730) in smokers. Smoking is related to higher sedentary behavior, despite the suitable PADL. An appropriate PADL did not reduce the deleterious effects of smoking on physical capabilities. Interrupting sedentary behavior may be an appropriate intervention target in smokers for reducing the risk of diseases.

Resumo O comportamento sedentário pode desempenhar papel importante nos resultados relacionados à saúde, independentemente da quantidade de atividade física na vida diária (AFVD). Nosso objetivo foi avaliar e comparar o comportamento sedentário, bem como a capacidade funcional em tabagistas e não tabagistas fisicamente ativos. Vinte e oito tabagistas adultos e 38 não tabagistas sem doenças respiratórias foram pareados por idade, sexo, índice de massa corporal, composição corporal, risco cardiovascular e AFVD moderada a intensa. Os participantes realizaram espirometria, teste de exercício cardiopulmonar (TECP), teste de caminhada de seis minutos (TC6), dinamometria isocinética e composição corporal (bioimpedância). Apesar da quantidade semelhante de AFVD moderada a intensa (mediana, 4,5h/semana para tabagistas e 4,0h/semana para os não tabagistas), os tabagistas passaram mais tempo deitados (mediana, 8,2h/semana: intervalo de confiança de 95%, 5,4 a 19,1 vs. 6,1h/semana: 3,7 a 11,2) e em atividades sedentárias (mediana, 100h/semana: 66 a 129 vs. 78h/semana: 55 a 122) em comparação com não tabagistas. Os tabagistas também apresentaram pior espirometria, pico de V’O2 e freqüência cardíaca máxima no TECP, TC6 e índices isocinéticos (p<0,05). Observamos uma forte correlação entre o tempo gasto deitado e a espirometria (r = - 0,730) nos tabagistas. O tabagismo está relacionado ao maior comportamento sedentário, apesar do nível AFVD adequado. Um nível AFVD adequado não reduziu os efeitos deletérios do tabagismo na capacidade funcional. Interromper o comportamento sedentário pode ser uma intervenção apropriada em tabagistas para a prevenção de doenças.

Association between physical activity in daily life and pulmonary function in adult smokers / Associação entre o nível de atividade física na vida diária e a função pulmonar em tabagistas adultos

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.

Objetivo: Determinar se há associações entre o nível de atividade física na vida diária (AFVD) e a função pulmonar em tabagistas adultos. Métodos: Foram selecionados 62 tabagistas adultos de um estudo epidemiológico, realizado na cidade de Santos (SP). Os participantes realizaram o teste de espirometria forçada para a avaliação da função pulmonar. O nível de AFVD foi avaliado pelo Questionário Internacional de Atividade Física e por acelerometria triaxial (aparelho utilizado por sete dias). O nível mínimo de AFVD, em termos de quantidade e intensidade, foi definido como 150 min/semana de atividade física moderada a vigorosa durante o monitoramento. As correlações entre as variáveis estudadas foram avaliadas pelo coeficiente de correlação de Pearson ou de Spearman conforme a distribuição das variáveis. A influência de AFVD nas variáveis espirométricas foi avaliada por meio de análise de regressão múltipla linear. O nível de significância foi estipulado em 5%. Resultados: Quando avaliados todos os preditores corrigidos para fatores de confusão e utilizando dados da função pulmonar como variáveis de desfecho, não foram observadas associações significativas entre a inatividade física avaliada por acelerometria e os índices espirométricos. As análises mostraram valores inferiores da CVF em participantes com hipertensão arterial e da relação VEF1/CVF nos participantes com diabetes mellitus. Os participantes obesos e os dislipidêmicos apresentaram valores inferiores de CVF e VEF1. Conclusões: Nossos resultados sugerem que a inatividade física apresenta associação pouco consistente com a função pulmonar de tabagistas adultos. A carga tabágica, assim como comorbidades cardiovasculares e metabólicas, deveriam ser priorizadas em estratégias preventivas da DPOC.