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.

Profile of adults users of smartphone applications for monitoring the level of physical activity and associated factors: A cross-sectional study

Background

There are currently more than 200 million smartphones in Brazil. The potential of mobile technologies for favorable changes in health behavior such as physical activity has been previously described in the literature. Results of surveys in developed countries indicate that applications (APPs) are developed for people who are better educated, younger, and with higher incomes compared to non-users. However, the profile of users in developing countries like Brazil is not well-known. Understanding the profile of APP users might ease the development turned to physically inactive people and those at higher cardiovascular risk. Furthermore, the physiological and functional factors associated with the use of such APP are unknown.

Objectives

To characterize the profile of APP users to monitor the physical activity level (PAL) and assess the demographic, socioeconomic, clinical, physiological, and functional characteristics associated with the use of smartphone APPs to monitor physical activity in Brazilian adults.

Methods

We assessed 176 asymptomatic men and 178 women (43 ± 12 years; 27 ± 5 kg/m2). We initially asked participants about their current use of a smartphone APP containing PAL monitoring functionality, such as exercise session logs and/or step counts. In a cross-sectional design, we investigated schooling, socioeconomic status (Critério Brasil), and classic self-reported cardiovascular risk factors. We evaluated several physiological and functional variables such as maximum O2 consumption on a treadmill (VO2 max), blood pressure, body composition (bioelectrical impedance), handgrip strength, and isokinetic muscle strength of the dominant lower limb. Participants used a triaxial accelerometer for 7 days to quantify daily physical activity. We also assessed health-related quality of life (WHOQOL BREF), perceived stress (PSS14 Scale), and the built environment (NEWS Scale). We compared continuous variables using the Student's t-test and categorical variables using the χ2 test, between APP users and non-users. After univariate analysis, we included the main variables associated with the use of APP in a multiple logistic regression model.

Results

One hundred and two participants (28.3%), unrelated to gender, reported using a smartphone APP for physical activity at the time of assessment. Except for perceived stress and the built environment that were not associated with the use of APP, users of APP were younger and had higher education, lower cardiovascular risk, better socioeconomic status, a better quality of life, better cardiorespiratory function, better body composition, greater physical fitness and more moderate to vigorous physical activity in daily life. The results of the multiple logistic regression showed that age, hypertension, VO2 max, socioeconomic status (Critério Brasil), and quality of life (WHOQOL BREF total score) were the variables most significantly associated with the use of the APP.

Conclusions

Our results indicate that smartphone APPs to monitor physical activity are developed for younger adults with better socioeconomic status, lower cardiovascular risk, higher quality of life, and greater cardiorespiratory fitness. Greater efforts are needed to develop a science-based APP for people who most need this technology, enabling greater potential to prevent undesirable health outcomes in asymptomatic adults.

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.

Cardiorespiratory fitness as a mediator in the relationship between lung function and blood pressure in adults

It is unclear whether physical activity and cardiorespiratory fitness (CRF) are pathways that link low pulmonary function (LPF) to increased blood pressure (BP). Therefore, we investigated the extent to which CRF and moderate-to-vigorous physical activity (MVPA) mediate the relationship between LPF and high BP in adults. We conducted a cross-sectional study with 1,362 participants that underwent cardiopulmonary exercise testing (CPET), spirometry, and wore an accelerometer to determine physical activity patterns. We performed mediation analyses using structural equations considering peak oxygen uptake (V̇O₂) and MVPA as mediators, forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) as independent variables, and systolic and diastolic blood pressure (SBP, DBP) as dependent variables. The probability of alpha error was set at 5%. We found a significant total effect of FVC on SBP and DBP considering V̇O₂ as mediator (P<0.01). Indirect effects were also significant, with 42.6% of the total effect of FVC on SBP and 77% on DBP mediated by V̇O₂ (P<0.01). We did not observe a direct effect of FVC on SBP and DBP. Considering FEV1 as an independent variable, the total effect on SBP was also significant, as were the indirect effects, mediated by V̇O₂ at 14.8% for SBP and 7.6% for DBP (P<0.01). We did not find an indirect effect of FVC or FEV1 considering the MVPA as a mediator. CRF mediates the pathway that links LPF and elevated BP. Therefore, CRF is more sensitive to variations in FVC and FEV1 than MVPA.

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.

Factors related to the adoption and adherence of physical activity mobile applications by older people: a scoping review protocol

INTRODUCTION

Ageing is a natural process marked by physiological changes and declines in functional capacity. One strategy to encourage healthy habits in older people is the use of applications on mobile devices to promote physical activity (PA). An immediate challenge is for these applications to be accessible to older people themselves, while a second challenge is to retain their interest and engagement in connection with PA itself. Therefore, the purpose of this review is to map the factors related to the adoption and adherence of PA mobile applications by older people.

METHODS AND ANALYSIS

Five databases will be searched where articles and reviews, available between 2010 and present, in English, Portuguese or Spanish, at full text, will be included. In addition, two additional strategies will be performed, including grey literature. The search terms adoption, adherence, factors, mobile application, PA, older people and other terms related to them will be used in the search strategy. This review will include studies that identify factors related to the adoption and adherence to PA mobile applications by people over 60 years. The selection of studies will be carried out by two reviewers in five stages: identification of studies and duplicate removal; pilot test; selection by reading abstracts; inclusion by reading the full text and search in additional sources. Disagreements will be resolved by a third reviewer. Data will be extracted using a data extraction tool. Quantitative data will be described in a narrative manner and qualitative data will be categorised through inductive thematic analysis.

ETHICS AND DISSEMINATION

Ethical approval is not required for this scoping review. Plans for the dissemination of the review include the presentation of the results at relevant scientific conferences and the submission and publication in significant journals.

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.

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: β 6.0, p = 0.213, 95%CI -3.5 to 15.6; in intermediate cardiorespiratory fitness: β 6.3, p = 0.114, 95%CI -1.5 to 14.2; in high cardiorespiratory fitness: β -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.

Classification of cardiorespiratory fitness using the six-minute walk test in adults: Comparison with cardiopulmonary exercise testing

BACKGROUND

The six-minute walk test (6MWT) distance could facilitate the assessment of cardiorespiratory fitness (CRF) in clinical practice as recommended. We aimed to develop a CRF classification using the 6MWT distance in asymptomatic adults considering the treadmill maximum oxygen uptake (V˙O_2max) as the gold standard method.

METHODS

We evaluated V˙O_2max and 6MWT distance in 1295 asymptomatic participants aged 18-80 years (60% women). Age- and sex-related CRF was classified based on the percentiles as very low (<5th percentile), low (5th-25th percentile), regular (26th-50th percentile), good (51st-75th percentile), excellent (76th-95th percentile), and superior (>95th percentile) for both V˙O_2max and 6MWT distance. We investigated the 6MWT distance cut-off (%pred.) with the highest sensitivity and specificity for identifying each V˙O_2max classification.

RESULTS

V˙O_2max declined by 8.7% per decade in both men and women. The 6MWT distance declined by 9.3% per decade in women and 9.5% in men. We formulated age- and sex-related classification tables for CRF using the 6MWT distance. Moreover, the 6MWT distance (%pred.) showed excellent ability to identify very low CRF (6MWT distance ≤ 96%; AUC=0.819) and good ability to differentiate CRF as low (6MWT distance=97%-103%; AUC=0.735), excellent (6MWT distance=107%-109%; AUC=0.715), or superior (6MWT distance>109%; AUC=0.790). It was not possible to differentiate between participants with regular and good CRF.

CONCLUSION

The CRF classification by the 6MWT distance is valid in comparison with V˙O_2max, especially for identifying adults with low CRF. It could be useful in clinical practice for screening and monitoring the cardiorespiratory risk in adults.

Current Activities Centered on Healthy Living and Recommendations for the Future: A Position Statement from the HL-PIVOT Network

We continue to increase our cognizance and recognition of the importance of healthy living (HL) behaviors and HL medicine (HLM) to prevent and treat chronic disease. The continually unfolding events precipitated by the coronavirus disease 2019 (COVID-19) pandemic have further highlighted the importance of HL behaviors, as indicated by the characteristics of those who have been hospitalized and died from this viral infection. There has already been recognition that leading a healthy lifestyle, prior to the COVID-19 pandemic, may have a substantial protective effect in those who become infected with the virus. Now more than ever, HL behaviors and HLM are essential and must be promoted with a renewed vigor across the globe. In response to the rapidly evolving world since the beginning of the COVID-19 pandemic, and the clear need to change lifestyle behaviors to promote human resilience and quality of life, the HL for Pandemic Event Protection (HL-PIVOT) network was established. The 4 major areas of focus for the network are: (1) knowledge discovery and dissemination; (2) education; (3) policy; (4) implementation. This HL-PIVOT network position statement provides a current synopsis of the major focus areas of the network, including leading research in the field of HL behaviors and HLM, examples of best practices in education, policy, and implementation, and recommendations for the future.

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 (∆R² = 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 (∆R² = 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.

The Design and Development of a Personalized Leisure Time Physical Activity Application Based on Behavior Change Theories, End-User Perceptions, and Principles From Empirical Data Mining

Introduction: Many adults do not reach the recommended physical activity (PA) guidelines, which can lead to serious health problems. A promising method to increase PA is the use of smartphone PA applications. However, despite the development and evaluation of multiple PA apps, it remains unclear how to develop and design engaging and effective PA apps. Furthermore, little is known on ways to harness the potential of artificial intelligence for developing personalized apps. In this paper, we describe the design and development of the Playful data-driven Active Urban Living (PAUL): a personalized PA application.

Methods: The two-phased development process of the PAUL apps rests on principles from the behavior change model; the Integrate, Design, Assess, and Share (IDEAS) framework; and the behavioral intervention technology (BIT) model. During the first phase, we explored whether location-specific information on performing PA in the built environment is an enhancement to a PA app. During the second phase, the other modules of the app were developed. To this end, we first build the theoretical foundation for the PAUL intervention by performing a literature study. Next, a focus group study was performed to translate the theoretical foundations and the needs and wishes in a set of user requirements. Since the participants indicated the need for reminders at a for-them-relevant moment, we developed a self-learning module for the timing of the reminders. To initialize this module, a data-mining study was performed with historical running data to determine good situations for running.

Results: The results of these studies informed the design of a personalized mobile health (mHealth) application for running, walking, and performing strength exercises. The app is implemented as a set of modules based on the persuasive strategies “monitoring of behavior,” “feedback,” “goal setting,” “reminders,” “rewards,” and “providing instruction.” An architecture was set up consisting of a smartphone app for the user, a back-end server for storage and adaptivity, and a research portal to provide access to the research team.

Conclusions: The interdisciplinary research encompassing psychology, human movement sciences, computer science, and artificial intelligence has led to a theoretically and empirically driven leisure time PA application. In the current phase, the feasibility of the PAUL app is being assessed.

Tailoring digital apps to support active ageing in a low income community

Despite physical activity being one of the determinants of healthy aging, older people tend to become less active over the years. Maintaining physical activity levels during the life course is a motivational challenge. Digital tools have been used to change this pattern, such as smartphone applications to support physical activity; but there is a lack of in-depth research on the diversity of user's experiences, especially considering older users or non-users of information and communication technologies.

OBJECTIVE

Our goal was to identify requirements for designing a mobile app to encourage physical activity in a low-income community population of older people in Brazil (i.e. over 40 years old).

METHOD

We conducted a qualitative focus group study, involving by co-design of a physical activity application (Pacer)®. Seventeen volunteers were divided into 2 focus groups of physical active and insufficiently active, and 2 further 4 subgroups in each characterised by digital engagement. The following procedures were performed: (i) baseline assessments; (ii) a focus group with physically active older people and a focus group with insufficiently active older people (iii) design activities with both groups to re-design Pacer.

RESULTS

Developing physical activity apps for older people should consider the following features: free application, simple interface, motivational messages using audio and visual information, sharing information among users, multimedia input and sharing and user customisation. In particular, we recommend that exercise apps in low-income communities be tailored to our four categories of users differing in baseline physical activity and digital engagement, to match the social and behavioural preferences we discovered.

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/.

Pattern of respiratory muscle activity during exercise tests in children born prematurely

INTRODUCTION

Preterm children display only slightly lower exercise capacity than term children do during their development, despite their previous cardiopulmonary impairments. This raises doubts about the role of the respiratory muscles' influence on exercise capacity. This study aimed to compare respiratory muscle activity in preterm and term children using an exercise test.

METHODS

This cross-sectional study involved comparison of 35 term children and 39 matched preterm children aged 6-9 years, who were born prematurely with a birth weight <1500 g. An adapted treadmill incremental test was utilized and surface electromyography of the sternocleidomastoid (SCM), upper trapezius (UT), and rectus abdominis (RA) muscles was performed. The root mean square was calculated every minute and compared between and within groups. A Monte Carlo simulation was also applied, and the area under the curve was calculated to evaluate the differences between groups.

RESULTS

During the entire exercise, the SCM muscle activity was higher in preterm children with a larger area under the curve than in the term children. There was no difference in the RA and UT muscle activity between groups throughout the test.

CONCLUSION

The results suggest a greater contribution of the SCM muscle sin preterm children's performance than in term children's performance during high-intensity exercises.

TRIAL REGISTRATION

Brazilian Clinical Trial Registry (ReBec) - RBR-89hr2h.

Effects of the juçara fruit supplementation on metabolic parameters in individuals with obesity: a double-blind randomized controlled trial

Adipose tissue inflammation has been proposed as a central mechanism connecting obesity with its metabolic and vascular complications due to the imbalance in the expression of several hormones and adipokines. Berries rich in polyphenols and unsaturated fatty acids have been able to prevent both obesity and adipose tissue inflammation, improving metabolic functions in human subjects and animal models of obesity. Juçara has been considered a super fruit owing to its nutritional composition and relevant biological activities with an interesting response in animals. Thus, we aimed to verify the potential antiobesogenic effect of juçara supplementation in humans. We conducted a double-blind, placebo-controlled, randomized trial with 35 adults with obesity of both sexes. They were assessed for resting metabolic rate, anthropometry and body composition, blood pressure, metabolic parameters and adipokines. Subsequently, they were randomized into two groups to use or not (placebo) 5 g lyophilized juçara for 6 weeks. Supplementation with juçara was significantly effective in reducing body fat, increasing high-density lipoprotein cholesterol and doubling serum adiponectin. Besides, juçara supplementation, high-density lipoprotein cholesterol and neck circumference were predictors to explain the enhancement in adiponectin. Juçara supplementation was determinant to improve adiponectin levels, and it may be considered a novel strategy for the treatment of obesity-related metabolic diseases.

Evaluation of Inflammatory Markers in Patients Undergoing a Short-Term Aerobic Exercise Program while Hospitalized due to Acute Exacerbation of COPD

INTRODUCTION

Acute exacerbation is an important factor for a worse prognosis in patients with chronic obstructive pulmonary disease (COPD). It promotes the increase of the inflammatory process and worsens quality of life, lung function, and muscle weakness. It is believed that physical exercise performed during the exacerbation breaks the vicious cycle of systemic manifestations without an increase in the inflammatory process.

OBJECTIVE

To evaluate the influence of short-term aerobic physical exercise during hospitalization on inflammatory markers. Patients and Methods. 26 patients were evaluated (69.2% female, FEV 137.5 ± 12.9%, and age 68.4 ± 11.6 years) 24 hours after hospitalization for smoking history, Charlson index, quality of life, systemic inflammatory markers, and body composition. After 48 hours of hospitalization, all patients underwent a 6-minute walk test (6MWT) and a new spirometry test, and BODE index was calculated. After 72 hours of hospitalization, patients in the intervention group underwent aerobic exercise on a treadmill for 15 minutes twice daily; before and after the aerobic exercise, blood samples were collected for evaluation of inflammatory markers. Finally, a month after hospital discharge, all patients were reevaluated according to systemic inflammatory markers, quality of life, body composition, spirometry, 6MWT, and BODE index.

RESULTS

Patients of both groups did not differ in severity of disease and general characteristics. The intervention group did not show worsening in the inflammatory process after aerobic activity: TNF-α from 1.19 (0 99-1.71) to 1.21 (0.77-1.53) (p = 0.58), IL-6 from 2.41 (2.02-0.58) to 2.66 (1.69-0.48) (p = 0.21), and CRP from 3.88 (2.26-8.04) to 4.07 (2.65-13.3) (p = 0.56). There was a negative correlation between the IL-6 marker and the 6MWT; that is, with the reduction in inflammatory levels, there was an improvement in exercise capacity one month after hospital discharge.

CONCLUSION

The present study showed that the aerobic physical activity initiated during hospitalization in patients with exacerbated COPD did not worsen the inflammatory process.

Effects of obesity on postural balance and occurrence of falls in asymptomatic adults

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.

Association between electromyographic localized muscle fatigue of the rectus femoris and static postural balance in physically active adult men

Abstract Although the determinant impact of exercise-induced muscle fatigue prior to postural balance assessment has been widely described, recent evidence suggests that hyperventilation and sensorimotor losses, rather than muscle fatigue, are responsible for the changes observed in postural balance. However, the association between localized muscle fatigue (LMF), induced by isokinetic dynamometer protocol test and assessed through surface electromyography, and postural balance in adults is poorly understood. We aimed to evaluate the association between the LMF of the rectus femoris and static postural balance in 51 adult men (43±14.8 years; 26.9±5 kg/m2). We obtained physical activity level and postural balance, respectively, through a triaxial accelerometry and a force platform. The quadriceps femoris strength and endurance were obtained using an isokinetic dynamometer and surface electromyography simultaneously. The association between the isokinetic and electromyographic LMF and static postural balance was investigated using linear regression models adjusted for age, body mass index, and isokinetic quadriceps strength and LMF. The correlations between postural balance variables and isokinetic muscle strength and LMF were weak-to-moderate. After multivariate analyses, we observed that electromyographic LMF were a predictor of postural balance, mainly of the mean amplitude and COP area and velocity in the mediolateral direction, regardless of isokinetic variables. Therefore, LMF plays a determinant role in the postural balance of physically active adult men. Fatigue indices are significant predictors of postural balance, regardless of previous fatigue induction.

Reliability measure of the rib cage deformity by a postural assessment software in patients with adolescent idiopathic scoliosis

Abstract Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity of the spine that generates changes in the biomechanics of the rib cage. Digital photogrammetry enables the recording of subtle changes and the interrelationship between parts of the human body that are difficult to measure by other means. The aim of this study was to create angles and thoracic distances and to evaluate the interobserver and intraobserver reliability of these measurements using the Software de Avaliação Postural (SAPO) in patients with AIS. This cross-sectional study evaluated 30 individuals aged between 11 and 18 years with AIS. We used SAPO with the thoracic markers in the form of angles (A) and distances (D) with involves structures like acromion, manubrium, xiphoid process, lower angle of the scapula, last false rib, anterior iliac spine process. Two experienced observers (A and B) analyzed the photos and all followed the same routine of analysis. Intraobserver and interobserver reproducibility was assessed by the Bland-Altman plot and intraclass correlation coefficient (ICC), while intraobserver and interobserver reliability was assessed by the T-Test and Wilcoxon's Test. A high repeatability index was obtained among the evaluations, with twelve of the sixteen variables considered as reliable in all statistical tests. The interobserver analyzes presented excellent correlation coefficients (ICC), showing good reliability for six of the sixteen variables proposed. The SAPO method presented good reproducibility and reliability for most of the thoracic markers created, showing that photogrammetry may be a complementary tool in the evaluation of thoracic alterations in patients with AIS.

Use of a smartphone app combined with gamification to increase the level of physical activity of adults and older adults: protocol of a sequential multiple assignment randomized trial

Background

There is scientific evidence suggesting that app-based interventions targeted to increase the level of physical activity might be effective, although multicomponent interventions appear to be more effective than app-based interventions alone. Despite the motivating results, it remains unclear whether or not app-based interventions can increase the level of physical activity and cardiovascular health. Our study aims to investigate the effect of a smartphone app combined with gamification on the level of physical activity of adults and older adults. The specific aims are (1) to verify the effects of the intervention on cardiometabolic and cardiovascular health, lung function, and cardiorespiratory fitness; and (2) to verify the relationship between age group and the response rate.

Methods/design

We will conduct a sequential multiple assignment randomized trial (SMART). The adaptive intervention protocol will last 6 months. After baseline assessments, participants will be randomized into one of three groups (group 1: app + tailored messages; group 2: app + tailored messages + gamification I; control group: physical activity counseling). For 12 weeks, we will record the average number of steps per day of participants from groups 1 and 2. At 6 weeks from initiation of recording, participants will be classified into responders and non-responders according to their increase in the average number of daily steps; all those considered as non-responders will be re-randomized, with the chance to participate in a third group – group 3: app + tailored messages + gamification II. Finally, at 12 weeks, participants will continue using the app but will no longer receive direct intervention from investigators. All participants will be reassessed at 3 and 6 months from baseline. Our pilot SMART will require 42 participants (14 per arm). Following the SMART pilot, we will calculate the sample size for the trial based on the variation of the average number of steps/day, including an up to 40% loss to follow-up and a less optimistic nonresponse rate of 65%.

Discussion

To our knowledge, this will be the first trial with adaptive intervention to test the effectiveness of using a smartphone app to increase the level of physical activity of adults and older adults.

Trial registration

Brazilian Clinical Trials Registry: RBR-8xtc9c. Registered on 3 August 2018, http://www.ensaiosclinicos.gov.br; UTN number: U1111–1218-1092.

Presence of age- and sex-related differences in heart rate variability despite the maintenance of a suitable level of accelerometer-based physical activity

There is currently a lack of information adjacent on the influence of sex and age in heart rate variability (HRV), adjusted according to accelerometer-based physical activity (PADL). We hypothesized that the effect of sex and age on the HRV should be reduced or absent in individuals with a suitable PADL level. We aim to evaluate the influence of sex and age on HRV, adjusted for the confounding effects of the PADL level. A total of 485 age-stratified subjects (18–39, 40–59, and ≥60 years) underwent HRV analyses at rest and 7-day assessments of accelerometer-based PADL. Multivariate analyses of covariance were done using log-transformed HRV indices as outcomes, age and sex as fixed factors, and PADL, cardiovascular risk, fat body mass, and heart rate (HR) at rest as covariates. Despite the adjustment for directly measured PADL, women had better indices of vagal tone, whereas men had higher sympathetic influence. Also, compared to middle-aged and older adults, younger individuals (ages 18–39 years) presented better HRV. Multiple regression analyses confirmed that age and sex were the main predictors of HRV indices, even after adjusting for PADL directly assessed by triaxial accelerometer and HR. We also observed that the correlation between some HRV indexes and the different indexes of physical activity directly evaluated was significant, but not very consistent. Thus, HRV indices are influenced by age and sex, regardless of accelerometer-based physical activity. Interventions with physical activity and exercise aimed at improving the autonomic modulation of asymptomatic adults should take such differences into account.

Aerobic Capacity of Preterm Children with Very Low Birth Weight at School Age and its Associated Factors

INTRODUCTION

Respiratory morbidities of preterm infants can cause significant ventilatory impairment thus compromising the aerobic capacity in childhood and adolescence. Therefore, the present study was conducted to evaluate the aerobic capacity in school age preterm children with VLBW and its associated factors.

METHODS

A cross-sectional study was conducted among preterm born with VLBW and term children, both aged 6-9 years. An individualized symptom-limited treadmill testing protocol performed aerobic capacity. Measured variables: oxygen pulse (PuO₂), percentage of maximum heart rate for age (%HR max), tidal volume/inspiratory capacity ratio (TV/IC), oxygen consumption (VO₂) peak, and the ratio of the anaerobic threshold of gas exchange to the predicted percentage of maximum VO₂ (VO₂@LA/%VO₂ max.pred.) were compared between groups. Univariate and multiple linear regression analyses were used to determine the factors associated with aerobic capacity.

RESULTS

Thirty-four preterm and 32 term children were included. Similar VO₂ peak and the other variables were observed. The development of bronchopulmonary dysplasia (BPD) and being obese/overweight was positively associated with %HR max. The Z-score for height/age and birth weight <1000g was positively associated with PuO₂ and peak VO₂, and negatively associated with overweight/obesity and female sex.

CONCLUSIONS

Aerobic capacity was similar in both groups. Sex, development of BPD, birth weight <1000g and factors related to body growth, such as Z-score for height/age and overweight/obesity, were associated with aerobic capacity in preterm children with VLBW.

Photobiomodulation via a cluster device associated with a physical exercise program in the level of pain and muscle strength in middle-aged and older women with knee osteoarthritis: a randomized placebo-controlled trial

Osteoarthritis (OA) is a chronic joint disease that leads to pain and functional incapacity. The aim of the study is to investigate the effects of the incorporation of photobiomodulation (PBM) (via cluster) into a physical exercise program on the level of pain, lower limb muscle strength, and physical capacity, in patients with knee OA. Sixty-two female volunteers with a diagnosis of knee OA were distributed in 4 groups: exercise associated with placebo PBM group, exercise associated with active PBM group, active PBM group, and placebo PBM group. Sixteen sessions of lower limb strength exercises and PBM via cluster (808 nm, 100 mW, 7 points each side, 56 J total) were performed. The level of pain, physical capacity, and lower limb muscle strength were evaluated with the use of the numeric pain rating scale (NPRS), 6-min walking test (6-MWT) and timed up and go (TUG), and maximal voluntary isometric torque (MVIT) before and after the interventions. Both groups presented a significant decrease in the level of pain when compared with the placebo-treated women. Furthermore, the 6-MWT showed that the trained groups (with or without PBM) demonstrated higher values in the distance walked comparing pre and post-treatment values. The same behavior was found for the MVIT load before and after intervention. TUG was higher for all the treated with exercise groups comparing the pre and post-treatment values. Physical exercise and PBM showed analgesic effects. However, PBM did not have any extra effect along with the effects of exercise in improving the distance walked, the TUG, and the muscle strength.Trial registration: RBR-7t6nzr.

FUNCTIONAL CAPACITY IN ADOLESCENT IDIOPATHIC SCOLIOSIS DURING THE POSTOPERATIVE PERIOD

ABSTRACT Introduction: Patients with Adolescent Idiopathic Scoliosis (AIS) show reduced exercise capacity during the Incremental Shuttle Walk Test (ISWT). However, we not know how patients behave in the late postoperative (LPO) period. Objective: The aim of this study was to evaluate the ISWT distance (ISWTD) and physiological responses during ISWT in AIS patients during the LPO period. Methods: We included 22 patients with AIS in the LPO period (SG) and 21 adolescents in the Control Group (CG). We assessed pulmonary function (FVC and FEV1). During ISWT, a gas analyzer was used to assess peak oxygen (VO2) and submaximal relations: Oxygen Uptake Efficiency Slope (OUES) and the breathing pattern (ΔVT/ΔlnVE). Results: Significantly lower values were observed in SG: VO2 (22 ± 5 vs. 27 ± 4), ISWTD (567 ± 94 vs.604 ± 86), FVC (2.70 ± 0.47 vs. 3.33 ± 0.52) and FEV1 (2.41 ± 0.46 vs. 2.84 ± 0.52). There were significant correlations between ISWTD and VO2/Kg (r = 0.80); between OUES and ΔVT/ΔlnVE (r = 0.65); and between the main thoracic curve with VO2/Kg (r= −0.61). Conclusion: AIS patients in the LPO period have significantly reduced exercise capacity associated with reduced lung function, residual spinal curve and cardiovascular deconditioning. Level of Evidence III; Prognostic Studies - Investigation of the effect of characteristic of a patient on the outcome of the disease.

High-intensity interval exercise promotes post-exercise hypotension of greater magnitude compared to moderate-intensity continuous exercise

PURPOSE

Physical exercise is associated with reduced blood pressure (BP). Moderate-intensity continuous exercise (MCE) promotes post-exercise hypotension (PEH), which is highly recommended to hypertensive patients. However, recent studies with high-intensity interval exercise (HIIE) have shown significant results in cardiovascular disease. Thus, this study aimed to analyze PEH in hypertensive subjects submitted to HIIE and compare it to post MCE hypotension.

METHODS

20 hypertensive adults (51 ± 8 years), treated with antihypertensive medications, were submitted to two different exercise protocols and a control session. The MCE was performed at 60-70% of VO₂ reserve, while HIIE was composed of five bouts of 3 min at 85-95% VO₂ reserve with 2 min at 50% of VO₂ reserve. The following variables were evaluated during exercise, pre- and post-session: clinical BP, heart rate (HR), double product, perception of effort, body mass, height and body mass index.

RESULTS

Systolic BP decreased after exercise in both sessions, showing greater decrease after HIIE (- 7 ± 10 and - 11 ± 12 mmHg, after MCE and HIIE, respectively, p ≤ 0.01). Diastolic BP also decreased after both sessions, but there were no significant differences between the two sessions (- 4 ± 8 and - 7 ± 8 mmHg, after MCE and HIIE, respectively).

CONCLUSION

Both exercise sessions produced PEH, but HIIE generated a greater magnitude of hypotension. The HIIE protocol performed in this study caused a greater cardiovascular stress during exercise; however, it was safe for the studied population and efficient for reducing BP after exercise.

The association between physical activity, sedentary behavior and the occurrence of falls in asymptomatic adults over 40 years old

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.

Reference values for the 6-min walk test in healthy middle-aged and older adults: from the total distance traveled to physiological responses

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.

Prevalence of exercise intolerance in obese adults undergoing cardiopulmonary exercise testing

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.

Use of cardiopulmonary exercise testing to assess early ventilatory changes related to occupational particulate matter

Spirometry has been used as the main strategy for assessing ventilatory changes related to occupational exposure to particulate matter (OEPM). However, in some cases, as one of its limitations, it may not be sensitive enough to show abnormalities before extensive damage, as seen in restrictive lung diseases. Therefore, we hypothesized that cardiopulmonary exercise testing (CPET) may be better than spirometry to detect early ventilatory impairment caused by OEPM. We selected 135 male workers with at least one year of exposure. After collection of self-reported socioeconomic status, educational level, and cardiovascular risk data, participants underwent spirometry, CPET, body composition assessment (bioelectrical impedance), and triaxial accelerometry (for level of physical activity in daily life). CPET was performed using a ramp protocol on a treadmill. Metabolic, cardiovascular, ventilatory, and submaximal relationships were measured. We compared 52 exposed to 83 non-exposed workers. Multiple linear regressions were developed using spirometry and CPET variables as outcomes and OEPM as the main predictor, and adjusted by the main covariates. Our results showed that OEPM was associated with significant reductions in peak minute ventilation, peak tidal volume, and breathing reserve index. Exposed participants presented shallower slope of ΔVT/ΔlnV̇E (breathing pattern), i.e., increased tachypneic breathing pattern. The OEPM explained 7.4% of the ΔVT/ΔlnV̇E variability. We found no significant influence of spirometric indices after multiple linear regressions. We conclude that CPET might be a more sensitive feature of assessing early pulmonary impairment related to OEPM. Our cross-sectional results suggested that CPET is a promising tool for the screening of asymptomatic male workers.

Dynamic physiological responses to the incremental shuttle walk test in adults

Abstract Introduction: Understanding the normal dynamic physiological responses to the incremental shuttle walk test might enhance the interpretation of walking performance in clinical settings. Objective: To assess dynamic physiological responses to the incremental shuttle walk test and its predictors in healthy adults. Methods: We assessed the simultaneous rates of changes of Δoxygen uptake/Δwalking velocity (ΔVO 2 /ΔWV), Δheart rate/Δoxygen uptake (ΔHR/ΔVO 2 ), Δventilation/Δcarbon dioxide production (ΔVE/ΔVCO 2 ), and Δtidal volume/Δlinearized ventilation (ΔVT/ΔlnVE) during the incremental shuttle walk test in 100 men and women older than 40 years. Fat and lean body masses (bioimpedance) were also evaluated. Results: We found that the dynamic relationships were not sex-dependent. Participants aged ≥ 70 presented declines in ΔVO 2 /ΔWV slope compared to those aged 40-49 (215 ± 69 vs. 288 ± 84 mL.min-1.km.h-1). Obese participants presented shallower slopes for ΔVO 2 /ΔWV (2.94 ± 0.90 vs. 3.84 ± 1.21 mL.min-1.kg-1.km.h-1) and ΔVT/ΔlnVE (0.57 ± 0.20 vs. 0.67 ± 0.26). We found negative influence of fat body mass on ΔVT/ΔlnVE (R2 = 0.20) and positive influence of lean body mass on ΔVO 2 /ΔWV (R2 = 0.31), ΔHR/ΔVO2 (R2 = 0.25), and ΔVT/ΔlnVE (R2 = 0.44). Conclusion: Dynamic relationships during walking were slightly influenced by age, but not sex-dependent. Body composition played an important role in these indices. Our results may provide better interpretation of walking performance in patients with chronic diseases.

Evaluation of waist-to-height ratio as a predictor of insulin resistance in non-diabetic obese individuals. A cross-sectional study

BACKGROUND

Insulin resistance (IR) and progressive pancreatic β-cell dysfunction have been identified as the two fundamental features in the pathogenesis of obesity and non-insulin-dependent diabetes mellitus. We aimed to investigate correlations between anthropometric indices of obesity and IR in non-diabetic obese individuals, and the cutoff value from receiver operating characteristic (ROC) curve analysis.

DESIGN AND SETTING

Cross-sectional study conducted in a private clinic.

METHODS

We included obese individuals (body mass index, BMI ≥ 30 kg/m2) with no diabetes mellitus (fasting glucose levels ≤ 126 mg/dl). The participants were evaluated for the presence of cardiovascular risk factors and through anthropometric measurements and biochemical tests. Furthermore, IR was assessed indirectly using the homeostatic model assessment (HOMA)-IR and HOMA-β indexes. The area underthe curve (AUC) of the variables was compared.The sensitivity, specificity and cutoff of each variable for diagnosing IR were calculated.

RESULTS

The most promising anthropometric parameters for indicating IR in non-diabetic obese individuals were waist-to-height ratio (WHtR), waist circumference (WC) and BMI. WHtR proved to be an independent predictor of IR, with risk increased by 0.53% in HOMA-IR, 5.3% in HOMA-β and 1.14% in insulin. For HOMA-IR, WHtR had the highest AUC value (0.98), followed by WC (0.93) and BMI (0.81). For HOMA-β, WHtR also had the highest AUC value (0.83), followed by WC (0.75) and BMI (0.73).The optimal WHtR cutoff was 0.65 for HOMA-IR and 0.67 for HOMA-β.

CONCLUSION

Among anthropometric obesity indicators, WHtR was most closely associated with occurrences of IR and predicted the onset of diabetes in obese individuals.

Test timed up and go and its correlation with age and functional exercise capacity in asymptomatic women

Abstract Introduction: The Timed Up and Go test (TUG) is widely used and valid in chronic patients, but rarely addressed in asymptomatic individuals. Objective: To assess the reliability, the age-related changes and the correlation between TUG and the Functional Exercise Capacity (FEC) adjusted for non-institutionalized middle-aged and elderly women. Methods: Ninety-eight women (57 ± 10 years) were selected and stratified into age groups. We have performed the tests TUG, Berg Balance Scale (BBS) and evaluation of usual gait speed (UGS). Fifty-eight participants (57 ± 10 years) also performed incremental shuttle walk test (ISWT). Results: Worse performance in TUG (p < 0,05) for participants aged ≥ 70 years for age groups 40-49 and 50-59 years. The reliability of TUG was excellent between the first and second TUG (intraclass correlation coefficient, 0.933; confidence interval of 95%, from 0.901 to 0.955) and between the second and third TUG (0.958, 0.938 to 0.972). The group of 58 participants who underwent further the ISWT, TUG correlated significantly (p <0.05) with ISWT (r = -0.72), VUM (r = -0.54) and BBS (r= 0.58). A multiple linear regression analysis selected TUG (R2 = 0.517) and VUM (R2 = 0.083) as determinants of FEC. Conclusion: TUG adapted for asymptomatic women is reliable and able to assess the decline of physical mobility with advancing age and it also crucial to the FEC.

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.

Does the incremental shuttle walk test require maximal effort in young obese women?

Obesity is a chronic disease with a multifaceted treatment approach that includes nutritional counseling, structured exercise training, and increased daily physical activity. Increased body mass elicits higher cardiovascular, ventilatory and metabolic demands to varying degrees during exercise. With functional capacity assessment, this variability can be evaluated so individualized guidance for exercise training and daily physical activity can be provided. The aim of the present study was to compare cardiovascular, ventilatory and metabolic responses obtained during a symptom-limited cardiopulmonary exercise test (CPX) on a treadmill to responses obtained by the incremental shuttle walk test (ISWT) in obese women and to propose a peak oxygen consumption (VO2) prediction equation through variables obtained during the ISWT. Forty obese women (BMI ≥30 kg/m2) performed one treadmill CPX and two ISWTs. Heart rate (HR), arterial blood pressure (ABP) and perceived exertion by the Borg scale were measured at rest, during each stage of the exercise protocol, and throughout the recovery period. The predicted maximal heart rate (HRmax) was calculated (210 - age in years) (16) and compared to the HR response during the CPX. Peak VO2 obtained during CPX correlated significantly (P<0.05) with ISWT peak VO2 (r=0.79) as well as ISWT distance (r=0.65). The predictive model for CPX peak VO2, using age and ISWT distance explained 67% of the variability. The current study indicates the ISWT may be used to predict aerobic capacity in obese women when CPX is not a viable option.

High sedentary behavior and compromised physical capabilities in adult smokers despite the suitable level of physical activity in daily life

DOI: http://dx.doi.org/10.5007/1980-0037.2017v19n1p62 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.

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.

Evaluation of dose-response relationship between smoking load and cardiopulmonary fitness in adult smokers: A cross-sectional study

OBJECTIVE

To evaluate the dose-response relationship between smoking load and cardiopulmonary fitness, as measured with cardiopulmonary exercise testing (CPET), in adult smokers free of respiratory diseases.

METHODS

After a complete clinical evaluation and spirometry, 95 adult smokers (35 men and 60 women) underwent CPET on a treadmill.

RESULTS

The physiological responses during CPET showed lower cardiorespiratory fitness levels, regardless of smoking load, with a peak [Formula: see text] lower than 100% of the expected value and a lower maximum heart rate. We observed a significant moderate negative correlation between smoking load and peak [Formula: see text] . The smoking load also presented a significant negative correlation with maximum heart rate(r=-0.36; p<0.05), lactate threshold(r=-0.45; p<0.05), and peak ventilation(r=-0.43; p<0.05). However, a dose-response relationship between smoking load quartiles and cardiopulmonary fitness was not found comparing quartiles of smoking loads after adjustment for age, sex and cardiovascular risk.

CONCLUSION

There appears to be no dose-response relationship between SL and cardiopulmonary fitness in adult smokers with preserved pulmonary function, after adjusting the analysis for age and cardiovascular risk. Our results suggest that smoking cessation might be useful as the primary strategy to prevent cardiopulmonary fitness decline in smokers, regardless of smoking load. Thus, even a very low dose of tobacco use must be avoided in preventive strategies focusing on becoming people more physically active and fit.

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.

Thoracic changes and exercise capacity in patients with adolescent idiopathic scoliosis

Abstract Introduction: The spine deformity due to adolescent idiopathic scoliosis (AIS) generates respiratory mechanical limitations that may reduce the physical activity performance. Objective: To evaluate the thoracic deformity, exercise capacity and lung function in AIS patients comparing to healthy adolescentes. Besides investigating associations between thoracic deformity and exercise capacity in AIS patients. Methods: Thirty-two AIS patients and 22 healthy adolescents underwent chest wall evaluation by photogrammetry. We created thoracic markers shaped as angles (A): A3 (xiphoid process and the last false rib on the right and left sides) and A5E (inframamilar / inferior angle of the scapula / left acromion). Individuals were submitted to incremental shuttle walk test (ISWT) and physiological responses were quantified: oxygen consumption (VO2), tidal volume (VT), minute ventilation (VE), the rate of gas exchange (R) and the walked distance (ISWD). Pulmonary function test was performed and the forced vital capacity (FVC) and expiratory volume in first second (FEV1) were obtained. Results: Patients with AIS presented FVC (p = 0.015), FEV1 (p = 0.044), VO2 (p = 0.015), VO2/kg (p = 0.008), VT (p < 0.001), VE (p = 0,010) and ISWD significantly reduced compared to healthy adolescents. We found moderate correlations between the thoracic markers A5E and VO2 (r = -0.480, p = 0.001), A3 and VE/VO2 (r = -0.480; p = 0.001) and R (r = -0.480, p = 0.001) in AIS patients. Conclusion: Patients with AIS presented reduced exercise capacity and reduced pulmonary function. The thoracic deformity is related to worse exercise capacity in individuals with AIS.

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.

Correlation between heart rate variability and pulmonary function adjusted by confounding factors in healthy adults

The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders.

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.

Functional exercise capacity, lung function and chest wall deformity in patients with adolescent idiopathic scoliosis

AbstractIntroduction The adolescent idiopathic scoliosis (AIS) causes changes on the compliance of the chest. These changes may be associated with impaired lung function and reduced functional exercise capacity of these adolescents. We aimed to evaluate the correlation between functional exercise capacity, lung function and geometry of the chest at different stages of AIS.Materials and methods The study was carried out in a cross-sectional design which were evaluated 27 AIS patients at different stages of the disease. For chest wall evaluation, were created geometry angles/distances (A/D), which were quantified by Software Postural Assessment. The functional exercise capacity was assessed by a portable gas analyzer during the incremental shuttle walk test (ISWT). Besides that, manovacuometry and spirometry were also performed.Results Linear regressions showed that oxygen uptake (peak VO2) was correlated with distance travelled in the ISWT (R2 = 0.52), maximal respiratory pressures, cough peak flow (R2 = 0.59) and some thoracic deformity markers (D1, D2 and A6).Discussion We observed that the chest wall alterations, lung function and respiratory muscle strength are related to the functional exercise capacity and may impair the physical activity performance in AIS patients.Final considerations There is correlation between functional exercise capacity, lung function and geometry of the chest in AIS patients. Our results point to the possible impact of the AIS in the physical activities of these adolescents. Therefore, efforts to prevent the disease progression are extremely important.

Intensity and physiological responses to the 6-minute walk test in middle-aged and older adults: a comparison with cardiopulmonary exercise testing

The 6-minute walk test (6MWT) is a simple field test that is widely used in clinical settings to assess functional exercise capacity. However, studies with healthy subjects are scarce. We hypothesized that the 6MWT might be useful to assess exercise capacity in healthy subjects. The purpose of this study was to evaluate 6MWT intensity in middle-aged and older adults, as well as to develop a simple equation to predict oxygen uptake (V˙O2) from the 6-min walk distance (6MWD). Eighty-six participants, 40 men and 46 women, 40-74 years of age and with a mean body mass index of 28±6 kg/m², performed the 6MWT according to American Thoracic Society guidelines. Physiological responses were evaluated during the 6MWT using a K4b2 Cosmed telemetry gas analyzer. On a different occasion, the subjects performed ramp protocol cardiopulmonary exercise testing (CPET) on a treadmill. Peak V˙O2 in the 6MWT corresponded to 78±13% of the peak V˙O2 during CPET, and the maximum heart rate corresponded to 80±23% of that obtained in CPET. Peak V˙O2 in CPET was adequately predicted by the 6MWD by a linear regression equation: V˙O2 mL·min^-1·kg^-1 = -2.863 + (0.0563×6MWD_m) (R²=0.76). The 6MWT represents a moderate-to-high intensity activity in middle-aged and older adults and proved to be useful for predicting cardiorespiratory fitness in the present study. Our results suggest that the 6MWT may also be useful in asymptomatic individuals, and its use in walk-based conditioning programs should be encouraged.