The impact of sleep duration on physical activity in daily life in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Despite the high prevalence of sleep disturbances in idiopathic pulmonary fibrosis (IPF), the relationship between physical activity in daily life (PADL) and sleep in this population remains unclear. OBJECTIVES: Investigate the impact of sleep on different domains of PADL in IPF and characterize their PADL profile. METHODS: Sixty-seven participants (thirty-three with IPF and thirty-four healthy subjects [control group]) were included. The subjects underwent assessments of pulmonary function, exercise capacity, respiratory and peripheral muscle strength, PADL, sleep, dyspnea, and health-related quality of life. PADL and sleep measures were assessed using an activity monitor (Actigraph®, wGT3x-BT). Associations between sleep and PADL were done using correlation and regression models. RESULTS: In the IPF, sleep duration at night associated significantly with step counts, sedentary, light, and moderate-to-vigorous physical activity (MVPA) (-0.82 ≤ R ≤ 0.43; p < .05 for all). Lung function and sleep partially explained PADL variables (0.19 ≤ R2 ≤ 0.65, p < .05 for all). Compared to controls, the IPF subjects presented lower step counts, less time spent in MVPA, standing position, and more time spent in lying position (p < .05, for all). CONCLUSIONS: Sleep duration is associated with PADL in IPF. The PADL profile of patients is worse than in control subjects.

Maximum Voluntary Ventilation and Its Relationship With Clinical Outcomes in Subjects With COPD.

BACKGROUND: Previous studies have reported that maximum voluntary ventilation (MVV) may be better associated with commonly used outcomes in COPD than FEV1 and may provide information on respiratory mechanics. In this study, we aimed to investigate the relationship between MVV and clinical outcomes in COPD and to verify whether MVV predicts these outcomes better than FEV1. METHODS: We conducted a cross-sectional study involving individuals with COPD. Lung function was assessed with spirometry; maximum inspiratory and expiratory pressures (PImax and PEmax, respectively) were assessed with manuvacuometry; and functional exercise capacity was assessed with the 6-min-walk test (6MWT). Dyspnea was assessed with the modified Medical Research Council (mMRC) scale; functional status was assessed with the modified Pulmonary Functional Status and Dyspnea Questionnaire (PFSDQ-m); and health status was assessed with the COPD Assessment Test (CAT). Correlations were verified with the Spearman coefficient, and stepwise multiple linear regression models investigated the predictors of clinical outcomes. RESULTS: Our study included 157 subjects: 82 males; median (interquartile range) age 66 (61-73) y; FEV1 46 (33-57) % predicted; 6MWT 86 (76-96) % predicted; PFSDQ-m total score 34 (14-57); and CAT total score 13 (7-19). Moderate correlations were found between MVV and PImax (r = 0.40), 6MWT (r = 0.50), mMRC (r = -0.56), and total scores on the PFSDQ-m (r = -0.40) and the CAT (r = -0.54). In the regression models, MVV was a predictor of almost all clinical outcomes, unlike FEV1. CONCLUSIONS: MVV correlates moderately with clinical outcomes commonly used in the evaluation of individuals with COPD, and MVV is a better predictor of respiratory muscle strength, functional exercise capacity, and patient-reported outcomes than FEV1.

Diagnosis, prevalence, and clinical impact of sarcopenia in COPD: a systematic review and meta-analysis.

Sarcopenia prevalence and its clinical impact are reportedly variable in chronic obstructive pulmonary disease (COPD) due partly to definition criteria. This review aimed to identify the criteria used to diagnose sarcopenia and the prevalence and impact of sarcopenia on health outcomes in people with COPD. This review was registered in PROSPERO (CRD42018092576). Five electronic databases were searched to August 2018 to identify studies related to sarcopenia and COPD. Study quality was assessed using validated instruments matched to study designs. Sarcopenia prevalence was determined using authors' definitions. Comparisons were made between people who did and did not have sarcopenia for pulmonary function, exercise capacity, quality of life, muscle strength, gait speed, physical activity levels, inflammation/oxidative stress, and mortality. Twenty-three studies (70% cross-sectional) from Europe (10), Asia (9), and North and South America (4) involving 9637 participants aged ≥40 years were included (69.5% men). Sarcopenia criteria were typically concordant with recommendations of hEuropean and Asian consensus bodies. Overall sarcopenia prevalence varied from 15.5% [95% confidence interval (CI) 11.8-19.1; combined muscle mass, strength, and/or physical performance criteria] to 34% (95%CI 20.6-47.3; muscle mass criteria alone) (P = 0.009 between subgroups) and was greater in people with more severe [37.6% (95%CI 24.8-50.4)] versus less severe [19.1% (95%CI 10.2-28.0)] lung disease (P = 0.020), but similar between men [41.0% (95%CI 26.2-55.9%)] and women [31.9% (95%CI 7.0-56.8%)] (P = 0.538). People with sarcopenia had lower predicted forced expiratory volume in the first second (mean difference -7.1%; 95%CI -9.0 to -5.1%) and poorer exercise tolerance (standardized mean difference -0.8; 95%CI -1.4 to -0.2) and quality of life (standardized mean difference 0.26; 95%CI 0.2-0.4) compared with those who did not (P < 0.001 for all). No clear relationship was observed between sarcopenia and inflammatory or oxidative stress biomarkers. Incident mortality was unreported in the literature. Sarcopenia is prevalent in a significant proportion of people with COPD and negatively impacts upon important clinical outcomes. Opportunities exist to optimize its early detection and management and to evaluate its impact on mortality in this patient group.

Influence of time under mechanical ventilation on bronchopulmonary dysplasia severity in extremely preterm infants: a pilot study.

BACKGROUND: The relation between mechanical ventilation (MV) and bronchopulmonary dysplasia (BPD) - a common disease in extremely premature newborn (PTNB) - is well stabilished, but is unknown, however, how much time under MV influences the severity of the disease. AIM: To define the duration under MV with greater chance to develop moderate to severe BPD in extremely PTNB and to compare clinical outcomes before and during hospitalization among patients with mild and moderate to severe BPD. METHODS: Fifty-three PTNB were separated into mild and moderate to severe BPD groups and their data were analyzed. Time under MV with a greater chance of developing moderate to severe BPD was estimated by the ROC curve. Perinatal and hospitalization outcomes were compared between groups. A logistic regression was performed to verify the influence of variables associated to moderate to severe BPD development, such as pulmonary hypertension (PH), gender, gestational age (GA) and weight at birth, as well the time under MV found with ROC curve. The result of ROC curve was validated using an independent sample (n = 16) by Chi-square test. RESULTS: Time under MV related to a greater chance of developing moderate to severe BPD was 36 days. Moderate to severe BPD group had more males (14 vs 5, p = 0,047), longer time under MV (43 vs 19 days, p < 0,001), more individuals with PH (12 vs 3, p = 0,016), worse retinopathy of prematurity (grade 3, 2 vs 11, p = 0,003), longer hospital length of stay (109 vs 81,5 days, p < 0,001), greater PMA (41 vs 38 weeks, p < 0,001) and weight (2620 vs 2031 g, p < 0,001) at discharge and the mild BPD group had more CPAP use prior to MV (12 vs 7, p = 0,043). Among all variables included in logistic regression, only PH and MV < 36 days were significant in the model, explaining 72% of variation in moderate to severe BPD development. In the validation sample, prevalence of preterm infants who needed MV for more than 36 days in the moderate to severe BPD group was 100% (n = 6) and 0% in mild BPD group (p = 0,0001). CONCLUSION: Time under MV related to moderate to severe BPD development is 36 days, and worst outcomes are related to disease severity. PH and time under MV for more than 36 days are related to development of moderate to severe BPD.

Effects of land- and water-based exercise programmes on postural balance in individuals with COPD: additional results from a randomised clinical trial.

OBJECTIVE: To investigate the effects of water-based exercise training on postural balance in individuals with chronic obstructive pulmonary disease (COPD), and compare the effects of two similar protocols of land- and water-based exercise programmes on postural balance in this population. DESIGN: Randomised clinical trial. SETTING: University-based, outpatient, physical therapy clinic. SUBJECTS: Fifty individuals with COPD. INTERVENTIONS: Participants were assigned at random to the land group (LG; n=27) or the water group (WG; n=23), and underwent high-intensity endurance and strength training three times per week for 3months. MAIN OUTCOME MEASURES: Functional balance was assessed by the timed up and go test (TUG), and static balance was assessed with a force platform in the following conditions: standing with feet hip-width apart and eyes open; standing with feet hip-width apart and eyes closed; standing on a short base; and one-legged stance. RESULTS: Seventeen subjects completed the intervention in the LG {nine males, mean age 64 [standard deviation (SD) 8] years, mean forced expiratory volume in 1 second (FEV1) 48 (SD 17) %predicted} compared with 14 subjects in the WG [nine males, mean age 65 (SD 8) years, FEV1 51 (SD 15) %predicted]. Water-based exercise training had a positive effect on functional balance [TUG: mean difference -1.17 (-1.93 to -0.41 95% confidence interval) seconds; P=0.006], whereas static balance remained unaltered for both groups. There was no between-group difference in postural balance after exercise training; however, a higher proportion of participants who had a clinically relevant improvement in the TUG were in the WG (LG 35%, WG 64%; P<0.001). CONCLUSION: Functional balance improved after 3months of high-intensity exercise training performed in water. Despite the environment, non-specific training seems to be insufficient to improve static balance. CLINICAL TRIAL REGISTRATION NUMBER: clinicalTrials.gov NCT01691131.

Best Protocol for the Sit-to-Stand Test in Subjects With COPD.

BACKGROUND: Different protocols for the sit-to-stand test (STS) are available for assessing functional capacity in COPD. We sought to correlate each protocol of the STS (ie, the 5-repetition [5-rep STS], the 30-s STS, and the 1-min STS) with clinical outcomes in subjects with COPD. We also aimed to compare the 3 protocols of the STS, to verify their association and agreement, and to verify whether the 3 protocols are able to predict functional exercise capacity and physical activity in daily life (PADL). METHODS: 23 subjects with COPD (11 men; FEV1 53 ± 15% predicted) performed 3 protocols of the STS. Subjects also underwent the following assessments: incremental shuttle walking test, 6-min walk test (6MWT), 4-m gait speed test (4MGS), 1-repetition maximum of quadriceps muscle, assessment of PADL, and questionnaires on health-related quality of life and functional status. RESULTS: The 1-min STS showed significant correlations with the 6MWT (r = 0.40), 4MGS (r = 0.64), and PADL (0.40 ≤ r ≤ 0.52), and the 5-rep STS and 30-s STS were associated with the 4MGS (r = 0.54 and r = 0.52, respectively). The speed differed for each protocol (5-rep STS 0.53 ± 0.16 rep/s, 30-s STS 0.48 ± 0.13 rep/s, 1-min STS 0.45 ± 0.11 rep/s, P = .01). However, they presented good agreement (intraclass correlation coefficient ≥ 0.73 for all) and correlated well with each other (r ≥ 0.68 for all). More marked changes in peripheral oxygen saturation (P = .004), heart rate (P < .001), blood pressure (P < .001), dyspnea (P < .001), and leg fatigue (P < .001) were found after the 1-min STS protocol. Furthermore, the 3 protocols were equally able to identify subjects with low exercise capacity or preserved exercise capacity. CONCLUSIONS: The 1-min STS generated higher hemodynamic demands and correlated better with clinical outcomes in subjects with COPD. Despite the difference in speed performance and physiological demands between the 5-rep STS and 1-min STS, there was a good level of agreement among the 3 protocols. In addition, all 3 tests were able to identify subjects with low exercise capacity or preserved exercise capacity.

Physical activity patterns and clusters in 1001 patients with COPD.

We described physical activity measures and hourly patterns in patients with chronic obstructive pulmonary disease (COPD) after stratification for generic and COPD-specific characteristics and, based on multiple physical activity measures, we identified clusters of patients. In total, 1001 patients with COPD (65% men; age, 67 years; forced expiratory volume in the first second [FEV1], 49% predicted) were studied cross-sectionally. Demographics, anthropometrics, lung function and clinical data were assessed. Daily physical activity measures and hourly patterns were analysed based on data from a multisensor armband. Principal component analysis (PCA) and cluster analysis were applied to physical activity measures to identify clusters. Age, body mass index (BMI), dyspnoea grade and ADO index (including age, dyspnoea and airflow obstruction) were associated with physical activity measures and hourly patterns. Five clusters were identified based on three PCA components, which accounted for 60% of variance of the data. Importantly, couch potatoes (i.e. the most inactive cluster) were characterised by higher BMI, lower FEV1, worse dyspnoea and higher ADO index compared to other clusters ( p < 0.05 for all). Daily physical activity measures and hourly patterns are heterogeneous in COPD. Clusters of patients were identified solely based on physical activity data. These findings may be useful to develop interventions aiming to promote physical activity in COPD.

Static and Functional Balance in Individuals With COPD: Comparison With Healthy Controls and Differences According to Sex and Disease Severity.

BACKGROUND: Studies have shown that individuals with COPD have impaired body balance, probably caused by the disease's multisystemic manifestations plus age-related decline in balance, potentially increasing the risk of falling and its consequences. However, little is known about the profile of individuals with COPD who present balance impairments, especially related to sex and disease severity stages. The aim of this work was to compare static and functional balance between subjects with COPD and healthy controls and to check possible differences according to sex and degrees of disease severity. METHODS: Forty-seven subjects with COPD and 25 healthy controls were included in this study. Their static balance was assessed in one-legged stance using a force platform and functional balance with the Timed Up and Go test. Additionally, participants performed spirometry, the 6-min walk test and isometric quadriceps maximal voluntary contraction assessment. Disease severity was classified according to the Global Initiative for Obstructive Lung Disease stages and BODE (body mass index, air-flow obstruction, dyspnea, and exercise capacity) scores. RESULTS: In comparison with healthy controls, subjects with COPD had worse static (center of pressure displacement area: 9.3 ± 1.9 cm2 vs 11.6 ± 4.0 cm2, respectively, P = .01) and functional balance (Timed Up and Go test: 8.5 ± 1.3 s vs 10.3 ± 1.8 s, respectively, P < .001). In the COPD group, men performed better in the Timed Up and Go test than women (9.8 ± 1.2 s vs 10.9 ± 2.2 s, respectively, P = .03), whereas women presented a better static balance in comparison with men for all parameters related to center of pressure (P < .005 for all). Disease severity did not affect any balance results. CONCLUSIONS: Individuals with COPD had worse static and functional balance in comparison with healthy controls. Sex can mediate these results, depending on the type of balance evaluation (force platform or functional test). Balance performance was similar among the groups classified according to disease severity.

Measurement properties of the Timed Up & Go test in patients with COPD.

We aimed to investigate the construct validity of the Timed Up & Go (TUG) test in chronic obstructive pulmonary disease (COPD), to identify characteristics related to an abnormal TUG time and to examine the responsiveness of the TUG to pulmonary rehabilitation (PR). TUG time was assessed before and after comprehensive PR in 500 COPD patients, and compared cross-sectionally in 100 non-COPD subjects. Physical health outcomes, mental health outcomes, symptom-related outcomes and multidimensional indices were assessed in COPD patients only. Good convergent and discriminant validity was demonstrated by fair-to-moderate correlation with physical health outcomes, symptom-related outcomes and multidimensional indices ( rs = 0.18-0.70) and by little correlation with mental health outcomes ( rs = 0.21-0.26). COPD patients had a worse TUG time than non-COPD subjects, demonstrating known-groups validity. A TUG time of 11.2 seconds had good sensitivity (0.75) and specificity (0.83) for identifying patients with a baseline 6-minute walk distance <350 m. TUG time improved after PR ( p < 0.0001) and a change of 0.9-1.4 seconds was identified as clinically important. The TUG is valid and responsive in COPD. An abnormal result is indicative of poor health outcomes. This simple test provides valuable information and can be adopted in clinical and research settings.

Angiotensin-II blockage, muscle strength, and exercise capacity in physically independent older adults.

[Purpose] This study aimed to assess the exercise capacity and muscle strength in elderly people using drugs for angiotensin-II blockage. [Subjects and Methods] Four hundred and seven older adults were recruited for this study. Data about comorbidities and medication use were recorded and the individuals were divided into three groups: control group- elderly people with normal exercise capacity (n=235); angiotensin-converting enzyme inhibitor group - individuals using angiotensin-converting enzyme inhibitors (n=140); and angiotensin-II receptor blocker group- patients using angiotensin-II receptor blockers (n= 32). Exercise capacity was evaluated by a 6-minute walking test and muscle strength was measured using a handgrip dynamometer. [Results] Patients from the angiotensin-converting enzyme inhibitor group (mean: 99 ± 12%) and the angiotensin-II receptor blocker group (mean: 101 ± 14%) showed higher predicted values in the 6-minute walking test than the control group patients (mean: 96 ± 10%). Patients from the angiotensin-converting enzyme inhibitor group (mean: 105 ± 19%) and the angiotensin-II receptor blocker group (mean: 105.1 ± 18.73%) showed higher predicted values of muscle strength than control group patients (mean: 98.15 ± 18.77%). [Conclusion] Older adults using angiotensin-converting enzyme inhibitors or angiotensin-II receptor blockers have better functional exercise capacity and muscle strength.

Can functional exercise capacity discriminate older individuals with poor postural control? / A capacidade funcional de exercício pode discriminar idosos com pior controle postural? / La capacidad funcional de ejercicio puede discriminar ancianos con mal control postural?

Postural instability can be related to functional limitations as a result of the aging process. This study aimed to compare functional exercise capacity and postural control in older adults. Participants were allocated into three groups according to their functional exercise capacity based on the six minute walking test (6MWT): 1) Low performance group (LP: distance walked ≤ 80% of the predicted value n = 19), 2) Normal performance group (NP: distance walked 81-100% of the predicted value n = 21) and, 3) High performance group (HP: distance walked >100% of the predicted value n = 23). All groups performed three trials of a one-leg stance for 30s on a force platform. LP showed worse postural control in comparison to NP and HP, and significant differences (p < .05) were found between groups for area, velocity antero-posterior of center of pressure and time limit variables during the one-leg stance task. These results have implications for rehabilitation management with regard to exercise, balance assessment and intervention in older adults.

Instabilidade postural pode estar relacionada com as limitações funcionais, como um resultado do processo de envelhecimento. Este estudo teve como objetivo comparar a capacidade funcional de exercício e o controle postural em indivíduos idosos. Os participantes foram separados em três grupos de acordo com sua capacidade funcional de exercício baseada no teste de caminhada de seis minutos (TC6min): 1) grupo baixo desempenho (BD: distância caminhada ≤ 80% do valor predito n = 19), 2) grupo normal desempenho (ND : distância caminhada 81-100% do valor predito n = 21) e, 3) grupo alto desempenho (AD: distância caminhada >100% do valor predito n = 23). Todos os grupos realizaram três testes com apoio unipodal permanecendo por 30s sobre a plataforma de força. BD apresentou pior equilíbrio postural em comparação com ND e AD; com diferenças significativas (p < 0,05) encontradas entre os grupos para os parâmetros de área e velocidade antero-posterior do centro de pressão e a variável tempo-limite durante a posição unipodal. Estes resultados têm implicações para estratégias de reabilitação no que diz respeito ao exercício, avaliação do equilíbrio e intervenção em idosos.

Inestabilidad postural puede estar relacionada con las limitaciones funcionales como resultado del proceso de envejecimiento. Este estudio tuvo como objetivo evaluar la comparación entre la capacidad funcional del ejercicio en el control postural de las personas de edad avanzada. Los participantes fueron divididos en tres grupos de acuerdo a su capacidad de ejercicio funcional basado en la Prueba de Caminada de seis minutos (PC6M): 1) grupo Bajo Rendimiento (BR: distancia recorrida ≤ 80% del valor predijo, n = 19), 2) grupo Normal Rendimiento (NR: distancia recorrida 81-100% del valor predijo, n = 21) y 3) grupo Alto Rendimiento (AR: distancia recorrida >100% del valor predijo, n = 23). Todos los grupos realizaron tres pruebas sobre un solo pie por 30s en la plataforma de fuerza. BR presentó un mal equilibrio postural en comparación con NR y AR; con diferencias significativas (p < 0,05) encontrado entre los grupos de los parámetros área y velocidad antero-posterior del centro de presión y el límite de tiempo para la postura de una sola pierna. Estos resultados tienen implicaciones para las estrategias de rehabilitación en relación con el ejercicio, la evaluación del equilibrio y la intervención en los ancianos.

Are 30 minutes of rest between two incremental shuttle walking tests enough for cardiovascular variables and perceived exertion to return to baseline values?

Objective: To verify whether 30 minutes of rest between two incremental shuttle walking tests (ISWT) are enough for cardiovascular variables and perceived exertion to return to baseline values in healthy subjects in a broad age range. Method: The maximal exercise capacity of 334 apparently healthy subjects (age ≥18) was evaluated using the ISWT. The test was performed twice with 30 minutes of rest in between. Heart rate (HR), arterial blood pressure (ABP), dyspnea, and leg fatigue were evaluated before and after each test. Subjects were allocated to 6 groups according to their age: G1: 18-29 years; G2: 30-39 years; G3: 40-49 years; G4: 50-59 years; G5: 60-69 years and G6: ≥70 years. Results: All groups had a good performance in the ISWT (median >90% of the predicted distance). The initial HR (HRi) of the second ISWT was higher than the first ISWT in the total sample (p<0.0001), as well as in all groups (p<0.0001). No difference was observed in the behavior of ABP (systolic and diastolic) and dyspnea between the two tests, but this difference occurred for leg fatigue (greater before the second ISWT) in G1 (p<0.05). Most subjects (58%) performed better in the second test. Conclusion: 30 minutes of rest between two ISWTs are not enough for all cardiovascular variables and perceived exertion to return to baseline values. However, this period appears to be sufficient for blood pressure and performance to recover in most subjects. .

Are 30 minutes of rest between two incremental shuttle walking tests enough for cardiovascular variables and perceived exertion to return to baseline values?

OBJECTIVE: To verify whether 30 minutes of rest between two incremental shuttle walking tests (ISWT) are enough for cardiovascular variables and perceived exertion to return to baseline values in healthy subjects in a broad age range. METHOD: The maximal exercise capacity of 334 apparently healthy subjects (age ≥ 18) was evaluated using the ISWT. The test was performed twice with 30 minutes of rest in between. Heart rate (HR), arterial blood pressure (ABP), dyspnea, and leg fatigue were evaluated before and after each test. Subjects were allocated to 6 groups according to their age: G1: 18-29 years; G2: 30-39 years; G3: 40-49 years; G4: 50-59 years; G5: 60-69 years and G6: ≥ 70 years. RESULTS: All groups had a good performance in the ISWT (median >90% of the predicted distance). The initial HR (HRi) of the second ISWT was higher than the first ISWT in the total sample (p<0.0001), as well as in all groups (p<0.0001). No difference was observed in the behavior of ABP (systolic and diastolic) and dyspnea between the two tests, but this difference occurred for leg fatigue (greater before the second ISWT) in G1 (p<0.05). Most subjects (58%) performed better in the second test. CONCLUSION: 30 minutes of rest between two ISWTs are not enough for all cardiovascular variables and perceived exertion to return to baseline values. However, this period appears to be sufficient for blood pressure and performance to recover in most subjects.

Does the Incremental Shuttle Walking Test require maximal effort in healthy subjects of different ages?

OBJECTIVE: To evaluate if the Incremental Shuttle Walking Test (ISWT) requires maximal effort in healthy subjects of different ages. DESIGN: Cross-sectional. SETTING: University-based research laboratory. PARTICIPANTS: 331 healthy subjects separated into six groups according to age: G1, 18 to 28 years; G2, 29 to 39 years; G3, 40 to 50 years; G4, 51 to 61 years; G5, 62 to 72 years and; G6, 73 to 83 years. MAIN OUTCOME MEASURES: Two ISWTs were performed and participants were permitted to run and to exceed 12 levels during the test, if necessary. Heart rate (HR) and symptoms of dyspnoea and fatigue were recorded before and after the test, and the percentage of age-predicted maximal HR (HRmax) was calculated. Maximal effort was defined as HRmax >90% of age-predicted HRmax. RESULTS: Almost 31% of the subjects exceeded 12 levels in the ISWT. At the end of the test, all groups presented a median [interquartile range] HR greater than 90% of HRmax (G1: 100 [95 to 104]; G2: 100 [96 to 105]; G3: 103 [97 to 108]; G4: 99 [91 to 106]; G5: 96 [87 to 106] and G6: 96 [91 to 109]% HRmax). Regarding symptoms, all groups showed higher values after the test (P<0.05). A multiple logistic regression analysis identified female gender, older age and a lower HR before the test as determinants of not achieving 90% of HRmax at the end of the test. CONCLUSIONS: The ISWT requires maximal effort in healthy individuals, but for that it is necessary to extend the test beyond twelve levels. Female gender, older age and lower heart rate before the test are the determinants of not reaching maximal effort.

Reference equations for the six-minute walk distance based on a Brazilian multicenter study

BACKGROUND: It is important to include large sample sizes and different factors that influence the six-minute walking distance (6MWD) in order to propose reference equations for the six-minute walking test (6MWT). OBJECTIVE: To evaluate the influence of anthropometric, demographic, and physiologic variables on the 6MWD of healthy subjects from different regions of Brazil to establish a reference equation for the Brazilian population. METHOD: In a multicenter study, 617 healthy subjects performed two 6MWTs and had their weight, height, and body mass index (BMI) measured, as well as their physiologic responses to the test. Delta heart rate (∆HR), perceived effort, and peripheral oxygen saturation were calculated by the difference between the respective values at the end of the test minus the baseline value. RESULTS: Walking distance averaged 586±106m, 54m greater in male compared to female subjects (p<0.001). No differences were observed among the 6MWD from different regions. The quadratic regression analysis considering only anthropometric and demographic data explained 46% of the variability in the 6MWT (p<0.001) and derived the equation: 6MWDpred=890.46-(6.11×age)+(0.0345×age2)+(48.87×gender)-(4.87×BMI). A second model of stepwise multiple regression including ∆HR explained 62% of the variability (p<0.0001) and derived the equation: 6MWDpred=356.658-(2.303×age)+(36.648×gender)+(1.704×height)+(1.365×∆HR). CONCLUSION: The equations proposed in this study, especially the second one, seem adequate to accurately predict the 6MWD for Brazilians. .

Reference equations for the six-minute walk distance based on a Brazilian multicenter study.

BACKGROUND: It is important to include large sample sizes and different factors that influence the six-minute walking distance (6MWD) in order to propose reference equations for the six-minute walking test (6 MWT). OBJECTIVE: To evaluate the influence of anthropometric, demographic, and physiologic variables on the 6 MWD of healthy subjects from different regions of Brazil to establish a reference equation for the Brazilian population. METHOD: In a multicenter study, 617 healthy subjects performed two 6 MWTs and had their weight, height, and body mass index (BMI) measured, as well as their physiologic responses to the test. Delta heart rate (∆HR), perceived effort, and peripheral oxygen saturation were calculated by the difference between the respective values at the end of the test minus the baseline value. RESULTS: Walking distance averaged 586 ± 106 m, 54 m greater in male compared to female subjects (p<0.001). No differences were observed among the 6 MWD from different regions. The quadratic regression analysis considering only anthropometric and demographic data explained 46% of the variability in the 6 MWT (p<0.001) and derived the equation: 6 MWD(pred)=890.46-(6.11 × age)+(0.0345 × age(2))+(48.87 × gender)-(4.87 × BMI). A second model of stepwise multiple regression including ∆HR explained 62% of the variability (p<0.0001) and derived the equation: 6 MWD(pred)=356.658-(2.303 × age)+(36.648 × gender)+(1.704 × height)+(1.365×∆HR). CONCLUSION: The equations proposed in this study, especially the second one, seem adequate to accurately predict the 6 MWD for Brazilians.

Respiratory muscle strength during and after hospitalization for COPD exacerbation.

BACKGROUND: A more profound investigation of respiratory muscle strength during COPD exacerbation was needed, so we investigated respiratory muscle strength and related factors in patients with COPD during and after hospitalization for COPD exacerbation. METHODS: In 19 subjects hospitalized for COPD exacerbation (12 males, mean age 67 ± 11 y, median percent-of-predicted FEV(1) 26% [IQR 19-32%]) we measured lung function and respiratory and quadriceps muscle strength at admission (day 1), at discharge, and 1 month after discharge. RESULTS: At admission, 68% of the subjects had inspiratory muscle dysfunction (maximum inspiratory pressure < 70% of predicted). Inspiratory muscle strength increased between day 1 (56 cm H(2)O [IQR 45-64 cm H(2)O]) and 1 month after discharge (65 cm H(2)O [IQR 51-74 cm H(2)O], P = .007). Expiratory muscle strength increased between day 1 (99 cm H(2)O [65-117 cm H(2)O]) and discharge (109 cm H(2)O [77-136 cm H(2)O], P = .005), and between day 1 and 1 month after discharge (114 cm H(2)O [90-139 cm H(2)O], P = .001). Inspiratory capacity increased between discharge (1.59 ± 0.44 L) and 1 month after discharge (1.99 ± 0.54 L, P = .02). There was no significant change in other lung function variables or quadriceps strength. At admission the inspiratory muscle dysfunction and reduction in inspiratory capacity (< 80% of predicted) correlated linearly (phi coefficient 0.62, P = .03), whereas the expiratory muscle strength correlated inversely with FEV(1) (Spearman rho -0.61, P = .005) and inspiratory capacity (Spearman rho -0.54, P = .02). CONCLUSIONS: There was a high prevalence of inspiratory muscle dysfunction in patients hospitalized for COPD exacerbation. Inspiratory and expiratory muscle strength increased markedly during and after hospitalization. The degree of air-flow obstruction and hyperinflation were related to inspiratory and expiratory muscle strength.

Physical activity in daily life in physically independent elderly participating in community-based exercise program / Atividade física na vida diária de idosos fisicamente independentes participantes de programas de exercício físico oferecidos à comunidade

BACKGROUND: It is unclear whether participation in exercise programs specifically developed for elderly translates into a more active lifestyle. OBJECTIVES: To compare the objectively measured level of physical activity in daily life (PADL) between physically independent elderly who participate or do not participate in community-based exercise programs; and to evaluate which factors are associated with the higher level of PADL in these subjects. METHOD: 134 elderly participants in community-based exercise programs (PG) and 104 non-participants (NPG) had their level of PADL measured using pedometers during 7 days. Other measurements: 6-minute walking test (6MWT), incremental shuttle walking test (ISWT), muscle strength, flexibility and balance. RESULTS: The PG had higher 1-week mean daily step count than NPG (8314 [IQR 5971-10060] vs. 6250 [IQR 4346-8207] steps/day, p<0.0001), as well as higher step count in any day of the week. There was a higher proportion of physically active subjects (>8000 steps/day) in PG than in NPG (37% vs. 16%, respectively; p<0.001), as well as the proportion of sedentary subjects (<5000 steps/day) (14% vs. 33%, respectively; p<0.001). Participation in exercise programs, 6MWT and ISWT explained a higher daily steps count (model r²=0.56, p<0.0001). CONCLUSIONS: In physically independent elderly, a higher level of physical activity in daily life occurs in those who participate in community-based exercise programs, regardless of the weekday and including non-program days. Participation of elderly in community-based exercise programs should be more systematically available and encouraged due to its close link to higher activity levels and better exercise capacity.

CONTEXTUALIZAÇÃO: Não está claro se a participação em programas de exercício físico específicos para idosos se traduz em um estilo de vida mais ativo. OBJETIVOS: Comparar o nível de atividade física na vida diária (AFVD) entre idosos fisicamente independentes (IFI) participantes e não participantes de programas de exercício oferecidos à comunidade e estudar os fatores associados ao maior nível de AFVD nesses indivíduos. MÉTODO: Cento e trinta e quatro IFI participantes de programas de exercício (GP) e 104 não participantes (GNP) tiveram seu nível de AFVD avaliado utilizando-se pedômetros durante sete dias. Outras avaliações foram teste de caminhada de 6 minutos (TC6min), incremental shuttle walking test (ISWT), força muscular, flexibilidade e equilíbrio. RESULTADOS: O GP apresentou maior média de passos/dia em sete dias do que o GNP (mediana [IRQ25%-75%] 8314[5971-10060] vs 6250[4346-8207] passos/dia, p<0,0001), bem como maior número de passos em qualquer dia da semana. Houve maior proporção de idosos fisicamente ativos (>8000 passos/dia) no GP em comparação com o GNP (37% vs 16%, respectivamente; p<0,001), assim como menor proporção de sedentários (<5000 passos/dia) (14% vs 33% respectivamente; p<0,001). Um modelo de regressão linear múltipla mostrou que participação em programas, TC6min e ISWT explicaram uma maior média de passos/dia (r²=0,56, p<0,0001). CONCLUSÕES: Em IFI, maior nível de AFVD ocorreu naqueles participantes de programas de exercício oferecidos à comunidade, mesmo analisando-se finais de semana e dias sem programa. A participação nesse tipo de programa deveria ser encorajada devido à sua relação com um estilo de vida mais ativo e melhor capacidade de exercício.

Physical activity in daily life in physically independent elderly participating in community-based exercise program.

BACKGROUND: It is unclear whether participation in exercise programs specifically developed for elderly translates into a more active lifestyle. OBJECTIVES: To compare the objectively measured level of physical activity in daily life (PADL) between physically independent elderly who participate or do not participate in community-based exercise programs; and to evaluate which factors are associated with the higher level of PADL in these subjects. METHOD: 134 elderly participants in community-based exercise programs (PG) and 104 non-participants (NPG) had their level of PADL measured using pedometers during 7 days. OTHER MEASUREMENTS: 6-minute walking test (6MWT), incremental shuttle walking test (ISWT), muscle strength, flexibility and balance. RESULTS: The PG had higher 1-week mean daily step count than NPG (8314 [IQR 5971-10060] vs. 6250 [IQR 4346-8207] steps/day, p<0.0001), as well as higher step count in any day of the week. There was a higher proportion of physically active subjects (>8000 steps/day) in PG than in NPG (37% vs. 16%, respectively; p<0.001), as well as the proportion of sedentary subjects (<5000 steps/day) (14% vs. 33%, respectively; p<0.001). Participation in exercise programs, 6MWT and ISWT explained a higher daily steps count (model r(2)=0.56, p<0.0001). CONCLUSIONS: In physically independent elderly, a higher level of physical activity in daily life occurs in those who participate in community-based exercise programs, regardless of the weekday and including non-program days. Participation of elderly in community-based exercise programs should be more systematically available and encouraged due to its close link to higher activity levels and better exercise capacity.

Postural balance and physical activity in daily life (PADL) in physically independent older adults with different levels of aerobic exercise capacity.

Balance impairs with aging and may cause mobility limitations and functional decline. We aimed to evaluate postural balance and PADL in physically independent older adults with different levels of exercise capacity. One hundred fifty seven physically independent individuals, aged 60 years or older were evaluated. Postural balance assessment was performed during one-legged stance test using a force-platform and maximum exercise capacity with the incremental shuttle walking test (ISWT). PADL was assessed subjectively by the modified Baecke questionnaire and objectively using a pedometer. Based on the performance achieved in the ISWT, according to the percentage of the predicted value, the older adults were separated into 3 groups: low performance group (LP group, ISWT < 80% predicted, n = 32, 19 women), normal performance group (NP group, 80 ≤ ISWT ≤ 100% predicted, n = 30, 22 women) and high performance group (HP group, ISWT > 100% predicted, n = 95, 67 women). The HP group showed better postural balance when compared to LP groups (p < 0.001) and also higher levels of PADL measured with pedometer (p < 0.001). There was a modest correlation (r = 0.45) between exercise capacity and PADL in the LP group and a weak correlation between exercise capacity and balance (r = -28) in the HP group. Physically independent older adults with more preserved exercise capacity have better postural balance and higher levels of PADL in comparison to those older adults who show a poorer condition in terms of exercise capacity.