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.

Physical activity and inactivity among different body composition phenotypes in individuals with moderate to very severe chronic obstructive pulmonary disease.

BACKGROUND: The phenotype profiling of individuals with chronic obstructive pulmonary disease (COPD) according to impairments in body composition and level of physical activity in daily life (PADL) needs to be determined. OBJECTIVE: To verify if individuals with COPD classified as physically active/inactive present different characteristics within different body composition phenotypes. METHODS: Individuals with COPD were cross-sectionally stratified into four groups according to fat-free and fat mass indexes: Normal Body Composition (NBC), Obese (Ob), Sarcopenic (Sarc), and Sarcopenic/Obese (Sarc/Ob). Additionally, individuals had their PADL level objectively assessed through activity monitoring during two weekdays for at least 10h/day, and then were classified as physically active (Act) or inactive (Inact) according to international recommendations. Lung function (spirometry), exercise capacity (6-minute walking test [6MWT]) and peripheral muscle strength (1-repetition maximum [1RM]) were also assessed. RESULTS: 176 individuals with COPD (mean±standard deviation age: 67±8 years, body mass index 26±6kg/m2, FEV1 47±16%predicted) were classified as: NBC+Act (17%), NBC+Inact (22%), Ob+Act (6%), Ob+Inact (10%), Sarc+Act (12%), Sarc+Inact (9%), Sarc/Ob+Act (8%) and Sarc/Ob+Inact (16%). The Sarc/Ob+Inact group presented lower 6MWT and 1RM for knee extension compared to NBC+Act, NBC+Inact, and Ob+Act groups (p<0.05). The Sarc/Ob+Inact group also presented lower FEV1% predicted, 1RM for elbow flexion and elbow extension compared to the NBC+Act and NBC+Inact groups and lower 1RM for elbow extension compared to Ob+Inact group (p<0.05). CONCLUSION: The combination of sarcopenia, obesity, and physical inactivity was shown to be detrimental in individuals with COPD. Therefore, this profile is a main therapeutic target for improving PADL level and/or body composition.

Elastic Resistance Training Produces Benefits Similar to Conventional Resistance Training in People With Chronic Obstructive Pulmonary Disease: Systematic Review and Meta-Analysis.

OBJECTIVE: The purpose of this study was to investigate the effectiveness of elastic resistance training on improving muscle strength, functional exercise capacity, health-related quality of life (HRQoL), and dyspnea in people with stable chronic obstructive pulmonary disease (COPD). METHODS: For this systematic review, PubMed, The Cochrane Library, Embase (OVID), PEDro, SciELO, and CINAHL were searched from inception to November 2019. Included studies were randomized clinical trials in which people with stable COPD were allocated to (1) an experimental group that received lower-limb resistance training, upper-limb resistance training, or both using elastic resistance; or (2) a control group that received no or sham resistance training or conventional resistance training using weight machines. Data extraction was performed by 3 review authors. The methodological quality of the studies was assessed using the PEDro scale. Eight studies on 332 participants were included. RESULTS: Knee extensor strength was higher in the experimental group (standardized mean difference = 0.52, 95% CI = 0.09-0.95) compared with the non-exercise control group. Compared with the conventional exercise control, the experimental group presented similar effects for muscle strength, functional exercise capacity, HRQoL, and dyspnea (95% CI overlapped the line of no effect for all). CONCLUSIONS: Elastic resistance training improves muscle strength in people with COPD. The current review suggests elastic resistance as a potential alternative to conventional resistance training using weight machines, as they show similar effects on muscle strength, functional exercise capacity, HRQoL, and dyspnea. IMPACT: Due to its beneficial effects, including reduced risk of exacerbation-related hospitalizations, exercise training is viewed as the cornerstone of pulmonary rehabilitation in people with COPD. This study shows that elastic resistance training can be an effective, portable, practical, and low-cost alternative to conventional weight resistance training. LAY SUMMARY: Training with elastic resistance tubes or bands-which are easy to carry, easy to use, and relatively low cost-can be an effective way to improve strength for people with COPD and promote similar benefits to those achieved with weight machines.

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.

Resistance Training With Elastic Tubing Improves Muscle Strength, Exercise Capacity, and Post-Exercise Creatine Kinase Clearance in Subjects With COPD.

BACKGROUND: Among the types of physical exercise, resistance exercises have been gaining significant attention in the COPD population. The aim of this study was to compare effects of conventional resistance training and of training by using elastic tubes on muscle strength, exercise capacity, and creatine kinase clearance in subjects with COPD. METHODS: Twenty-eight subjects with COPD were randomized into the following: resistance training with the elastic tubing group and resistance training with the weight-machine training group (conventional resistance group), performed 3 times a week for 12 weeks. The subjects were submitted to spirometry, functional exercise capacity (the 6-min walk test), muscle strength (dynamometry), and the repetition maximum test. Differences between the initial and final evaluations (Δ) and the (final - initial evaluations)/initial evaluations ×100 (Δ%) of each group were expressed as mean [95% CI]. RESULTS: Nineteen subjects (FEV1 % predicted, 52 ± 18; years, 65 ± 8) completed the training program. Similar improvements were observed in both modalities on muscle strength (knee extension, Δ%18 [6 to 29]; knee flexion, Δ%35 [17 to 54]; elbow flexion, Δ%28 [9 to 48]; shoulder abduction, Δ%41 [25 to 58] and shoulder flexion, Δ%31 [11 to 51] in the weight-machine training group (conventional resistance group); knee extension, Δ%15 [8 to 21]; knee flexion, Δ%28 [15 to 41]; elbow flexion, Δ%36 [22 to 51]; and shoulder abduction, Δ%43 [32 to 55] and shoulder flexion, Δ%43 [25 to 61] in the elastic tubing group, P < .05 for intra-group analysis and P > .05 for between groups analysis), 6-min walk test (baseline 493 ± 67m vs 12 weeks 526 ± 78 in the weight-machine training group (P = .10); baseline 493 ± 71 vs 12 weeks 524 ± 68 in the elastic tubing group (P < .01), P = .88 between groups). The elastic tubing group had lower accumulated creatine kinase levels between 24 and 72 h ((Δ%-24 [-31 to 16] than subjects in the weight-machine training group Δ%3 [-21 to 28], P = .042 between the groups. CONCLUSIONS: Training with elastic resistance provided similar changes in muscle strength and exercise capacity to conventional resistance group in the subjects with COPD. The elastic tubing group had faster creatine kinase clearance after a training session than the weight-machine training group (conventional resistance group). The ease of its application associated with similar training benefits to conventional training supported its application in clinical routine.

Resistance Training using Low Cost Elastic Tubing is Equally Effective to Conventional Weight Machines in Middle-Aged to Older Healthy Adults: A Quasi-Randomized Controlled Clinical Trial.

The objectives of the study were to compare the effects of resistance training using either a low cost and portable elastic tubing or conventional weight machines on muscle force, functional exercise capacity, and health-related quality of life (HRQOL) in middle-aged to older healthy adults. In this clinical trial twenty-nine middle-aged to older healthy adults were randomly assigned to one of the three groups a priori defined: resistance training with elastic tubing (ETG; n = 10), conventional resistance training (weight machines) (CTG; n = 9) and control group (CG, n = 10). Both ETG and CTG followed a 12-week resistance training (3x/week - upper and lower limbs). Muscle force, functional exercise capacity and HRQOL were evaluated at baseline, 6 and 12 weeks. CG underwent the three evaluations with no formal intervention or activity counseling provided. ETG and CTG increased similarly and significantly muscle force (Δ16-44% in ETG and Δ25-46% in CTG, p < 0.05 for both), functional exercise capacity (ETG Δ4 ± 4% and CTG Δ6±8%; p < 0.05 for both). Improvement on "pain" domain of HRQOL could only be observed in the CTG (Δ21 ± 26% p = 0.037). CG showed no statistical improvement in any of the variables investigated. Resistance training using elastic tubing (a low cost and portable tool) and conventional resistance training using weight machines promoted similar positive effects on peripheral muscle force and functional exercise capacity in middle-aged to older healthy adults.

Weaning failure and respiratory muscle function: What has been done and what can be improved?

INTRODUCTION: Respiratory muscle dysfunction, being a common cause of weaning failure, is strongly associated with prolonged mechanical ventilation (MV) and prolonged stay in intensive care units. Inspiratory muscle training (IMT) has been described as an important contributor to the treatment of respiratory muscle dysfunction in critically ill patients. Its effectiveness is however yet controversial. OBJECTIVE: To discuss evidence for assessment of readiness and the effectiveness of interventions for liberation from MV, with special attention to the role of IMT. METHODS: PubMed, LILACS, PEDro and Web of Science were searched for papers of assessment and treatment of patients who failed liberation from MV after at least one attempt published in English or Portuguese until June 2016. RESULTS: Weaning predictors are related to weaning success (86%-100% for sensitivity and 7%-69% for specificity) and work of breathing (73%-100% for sensitivity and 56%-100% for specificity). Spontaneous breathing trials (SBT), noninvasive MV and early mobilization have been reported to improve weaning outcomes. Two modalities of IMT were identified in five selected studies: 1) adjustment of ventilator trigger sensitivity 2) inspiratory threshold loading. Both IMT training modalities promoted significant increases in respiratory muscle strength. IMT with threshold loading showed positive effect on endurance compared to control. CONCLUSION: Methods to indentify respiratory muscle weakness in critically ill patients are feasible and described as indexes that show good accuracy. Individualized and supervised rehabilitation programs including IMT, SBT, noninvasive MV and early mobilization should be encouraged in patients with inspiratory muscle weakness.

Peripheral muscle training in patients with chronic obstructive pulmonary disease: novel approaches and recent advances.

INTRODUCTION: Pulmonary rehabilitation is one of the most effective non-pharmacological management options for individuals with chronic obstructive pulmonary disease (COPD). Exercise training is the cornerstone of pulmonary rehabilitation, however considerable variability exists regarding the way it is delivered across the world. It is widely accepted that efforts should be made to tailor specific therapeutic approaches to individuals' needs. This applies as much to respiratory medicine as it does to respiratory rehabilitation. Areas covered: This narrative review examines the emerging literature evaluating advancements of exercise training modalities targeting peripheral muscle function in people with COPD. It aims to highlight practical considerations regarding the delivery key evidence regarding clinical effectiveness, as well as highlight some of the and evaluation of their effectiveness to inform clinical practice. Expert commentary: Although novel therapies may offer advantages over more 'traditional' training methods under specific circumstances, challenges regarding the potential impact upon clinical rehabilitation, the identification of the best candidates for such therapy and access to equipment may pose realistic barriers to their more widespread clinical implementation. Future directions regarding the ways in which these barriers could be overcome will be discussed, including identification of the key research priorities to optimize evidence-based practice in this area.

Survival after pulmonary rehabilitation in patients with COPD: impact of functional exercise capacity and its changes.

The impact of rehabilitation-induced changes in 6-minute walk distance (6MWD) on the survival of patients with chronic obstructive pulmonary disease (COPD) has not been fully elucidated. This study sought to determine the association of baseline 6MWD and its changes after pulmonary rehabilitation (PR) with 5-year survival in patients with COPD. Patients who were referred to a 12-week outpatient PR program were followed up for 5 years postcompletion, and survival status was verified. Survival was analyzed according to four groups based upon initial 6MWD (6MWDi) and its changes (Δ6MWD) after PR (Group 1: 6MWDi ≥350 m and Δ6MWD ≥30 m; Group 2: 6MWDi ≥350 m and Δ6MWD <30 m; Group 3: 6MWDi <350 m and Δ6MWD ≥30 m; and Group 4: 6MWDi <350 m and Δ6MWD <30 m) via Kaplan-Meier analysis and log rank test. Cox regression was performed to identify possible confounders of mortality estimates. In total, 423 patients (with mean ± standard deviation of forced expiratory volume in the first second [FEV1] 43±16% predicted, age 65±8 years, and 6WMDi 381±134 m) underwent PR between 1999 and 2010. Survival rates decreased progressively from Group 1 to Group 4 (Group 1, 81%; Group 2, 69%; Group 3, 47%; Group 4, 27%; log rank test, P<0.05). 6MWDi ≥350 m (hazard ratio [HR] 0.39 [95% confidence interval {CI} 0.30-0.50]) and Δ6MWD ≥30 m (HR 0.66 [95% CI 0.51-0.85]) were strongly and independently associated with survival. Compared with Group 1, mortality risks progressively increased in Group 2 (HR 1.36 [95% CI 0.92-2.00]; not significant), Group 3 (HR 1.90 [95% CI 1.28-2.84]; P=0.001), and Group 4 (HR 3.28 [95% CI 2.02-5.33]; P<0.0001). Both poor 6MWD and lack of improvement >30 m after PR are associated with worse 5-year survival in patients with COPD.

Effect of "add-on" interventions on exercise training in individuals with COPD: a systematic review.

The aim of this review was to identify the effectiveness of therapies added on to conventional exercise training to maximise exercise capacity in patients with chronic obstructive pulmonary disease (COPD). Electronic databases were searched, identifying trials comparing exercise training with exercise training plus "add-on" therapy. Outcomes included peak oxygen uptake (V'O2peak), work rate and incremental/endurance cycle and field walking tests. Individual trial effects on exercise capacity were extracted and collated into eight subgroups and pooled for meta-analysis. Sensitivity analyses were conducted to explore the stability of effect estimates across studies employing patient-centred designs and those deemed to be of "high" quality (PEDro score >5 out of 10). 74 studies (2506 subjects) met review inclusion criteria. Interventions spanned a broad scope of clinical practice and were most commonly evaluated via the 6-min walking distance and V'O2peak. Meta-analysis revealed few clinically relevant and statistically significant benefits of "add-on" therapies on exercise performance compared with exercise training. Benefits favouring "add-on" therapies were observed across six different interventions (additional exercise training, noninvasive ventilation, bronchodilator therapy, growth hormone, vitamin D and nutritional supplementation). The sensitivity analyses included considerably fewer studies, but revealed minimal differences to the primary analysis. The lack of systematic benefits of "add-on" interventions is a probable reflection of methodological limitations, such as "one size fits all" eligibility criteria, that are inherent in many of the included studies of "add-on" therapies. Future clarification regarding the exact value of such therapies may only arise from adequately powered, multicentre clinical trials of tailored interventions for carefully selected COPD patient subgroups defined according to distinct clinical phenotypes.

Principles of rehabilitation and reactivation.

Skeletal muscle dysfunction and physical inactivity are two clinically important features of a wide range of acute and chronic respiratory conditions. Optimisation of both of these features is important in order to improve physical function, prevent clinical deterioration and maximise community participation. One of the most potent and evidence-based interventions to address these physical deficits is pulmonary rehabilitation (PR). Whilst the majority of PR research has been conducted in patients with chronic obstructive pulmonary disease, there is widespread recognition that PR can benefit many other respiratory patient groups. These include patients with interstitial lung diseases, asthma, pulmonary hypertension, pre-/post-lung surgery (e.g. lung cancer, transplantation) and cystic fibrosis to name a few. Exercise training must be appropriately prescribed by a skilled healthcare professional with comprehensive knowledge of the pathology and physiology of these conditions, as well as a sound understanding of the exercise physiology and core principles of exercise prescription, monitoring and progression. It has also become increasingly recognised that people with respiratory conditions, particularly those with chronic disease, are considerably less active than those of good health. PR should therefore aim to induce behavioural change to facilitate the adoption and maintenance of an active lifestyle. In addition, PR should pay attention to the psychological well-being of patients and self-management of their lung disease in all its aspects. To that end, multidisciplinary individualised programs should be offered. This review sets the scene of PR principles for a series of papers that will focus on specific diseases other than chronic obstructive pulmonary disease where rehabilitation may offer a clinically important aspect of care over and above conventional pharmacological treatment.

Pulmonary rehabilitation: timing, location, and duration.

Pulmonary rehabilitation programs vary in terms of duration and location. Differences also exists in the patients who are judged eligible for rehabilitation. This article reviews the options clinicians have to organize programs in terms of who should be referred, when, where, and for how long. There are several risk factors for lack of uptake and non-adherence to programs. Logistical aspects are also an important barrier. In terms of election, patients with muscle dysfunction are likely the best candidates for exercise training. Patients with exercise-induced symptoms and those after exacerbations should also be referred.

Evaluation of a new motion sensor in patients with chronic obstructive pulmonary disease.

OBJECTIVE: To assess the criterion validity and reproducibility of a new pedometer in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Cross-sectional study. SETTING: Outpatient physiotherapy clinic from a university hospital. PARTICIPANTS: Patients with COPD (N=30; 17 men; forced expiratory volume in the first second, 44±17% predicted) were videotaped while performing 2 protocols: one including 2 slow and 2 fast 5-minute walks, and another including a circuit of activities of daily living (ADLs). Concomitantly, patients wore 2 motion sensors: the new pedometer and a multisensor accelerometer. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Step counting (SC), energy expenditure (EE), walking distance (WD), activity time (AT), and walking intensity (WI) registered by the pedometer were compared with video and the multisensor as criterion methods. RESULTS: Correlations between the pedometer and the criterion method were high for SC during slow and fast walking (r=.79 and r=.95) and for EE during fast walking (r=.83). Correlation was more modest for EE during slow walking (r=.65) and for WD and WI during both speeds (.47.79 for all). During the ADLs circuit, the pedometer underestimated AT by an average of 55% but provided an acceptable EE estimation in a group basis (average difference of 6% with the multisensor). CONCLUSIONS: In patients with COPD, the new pedometer analyzed in the present study is reproducible for most outcomes and highly valid for SC during slow and fast walking and EE during fast walking. The device's validity is more limited for EE during slow walking, and WD and WI at both speeds. Furthermore, during the performance of ADLs, it significantly underestimates activity time but provides an acceptable estimation of EE in a group basis.

Effects of 2 exercise training programs on physical activity in daily life in patients with COPD.

BACKGROUND: The effects of different exercise training programs on the level of physical activity in daily life in patients with COPD remain to be investigated. OBJECTIVE: In patients with COPD we compared the effects of 2 exercise/training regimens (a high-intensity whole-body endurance-and-strength program, and a low-intensity calisthenics-and-breathing-exercises program) on physical activity in daily life, exercise capacity, muscle force, health-related quality of life, and functional status. METHODS: We randomized 40 patients with COPD to perform either endurance-and-strength training (no. = 20, mean ± SD FEV(1) 40 ± 13% of predicted) at 60-75% of maximum capacity, or calisthenics-and-breathing-exercises training (no. = 20, mean ± SD FEV(1) 39 ± 14% of predicted). Both groups underwent 3 sessions per week for 12 weeks. Before and after the training programs the patients underwent activity monitoring with motion sensors, incremental cycle-ergometry, 6-min walk test, and peripheral-muscle-force test, and responded to questionnaires on health-related quality of life and functional status (activities of daily living, pulmonary functional status, and dyspnea). RESULTS: Time spent active and energy expenditure in daily life were not significantly altered in either group. Exercise capacity and muscle force significantly improved only in the endurance-and-strength group. Health-related quality of life and functional status improved significantly in both groups. CONCLUSIONS: Neither training program significantly improved time spent active or energy expenditure in daily life. The training regimens similarly improved quality of life and functional status. Exercise capacity and muscle force significantly improved only in the high-intensity endurance-and-strength group.

Step counting and energy expenditure estimation in patients with chronic obstructive pulmonary disease and healthy elderly: accuracy of 2 motion sensors.

OBJECTIVE: To compare the accuracy of 2 motion sensors (a pedometer and a multisensor) in terms of step counting and estimation of energy expenditure (EE) in patients with chronic obstructive pulmonary disease (COPD) and in healthy elderly. DESIGN: In this descriptive study, all participants wore both motion sensors while performing a treadmill walking protocol at 3 different speeds corresponding to 30%, 60%, and 100% of the average speed achieved during a six-minute walk test. As criterion methods, EE was estimated by indirect calorimetry, and steps were registered by videotape. SETTING: Research laboratory at a university hospital. PARTICIPANTS: Patients with COPD (n=30; 17 men; mean age +/- SD, 67+/-8 y; mean forced expiratory volume in the first second [FEV(1)] predicted +/- SD, 46%+/-17%; mean body mass index [BMI] +/- SD, 24+/-4 kg.m(2)) and matched healthy elderly (n=30; 15 men; mean age +/- SD, 68+/-7 y; mean FEV(1) predicted +/- SD, 104%+/-21%; mean BMI +/- SD, 25+/-3 kg.m(2)). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Step counting and EE estimation during a treadmill walking protocol. RESULTS: The pedometer was accurate for step counting and EE estimation in both patients with COPD and healthy elderly at the higher speed. However, it showed significant underestimation at the 2 slower speeds in both groups. The multisensor did not detect steps accurately at any speed, although it accurately estimated EE at all speeds in healthy elderly and at the intermediate and higher speeds in patients with COPD. CONCLUSIONS: In both patients with COPD and healthy elderly, the multisensor showed better EE estimates during most walking speeds than the pedometer. Conversely, for step counting, accuracy is observed only with the pedometer during the higher walking speed in both groups.

Heart rate variability and disease characteristics in patients with COPD.

Heart rate variability (HRV) is reduced in patients with chronic obstructive pulmonary disease (COPD). However, the relationships among HRV and characteristics of COPD are unknown. The aim of this study was to characterize HRV in patients with COPD and to verify the correlation of HRV measured during rest with disease severity and pulmonary, muscular, and functional impairment. Thirty-one patients with COPD (16 male; 66 +/- 8 years; BMI = 24 +/- 6 kg/m(2); FEV(1) = 46 +/- 16% predicted) without severe cardiac dysfunction were included. HRV assessment was performed by the head-up tilt test (HUTT), and the main variables used for analysis were SDNN index, LF/HF ratio, and R-R intervals. Other tests included spirometry, bioelectrical impedance, cardiopulmonary exercise test, 6-minute walk test, respiratory and peripheral muscle force, health-related quality of life and functional status questionnaires, and objective quantification of physical activity level in daily life with the DynaPort and SenseWear armband activity monitors, besides calculation of the BODE index. There was a statistical difference in all variables of HRV between the HUTT positions (lying and standing). There was no correlation of HRV with BODE index or FEV(1). Out of the BODE index, just the BMI was correlated with SDNN and R-R intervals (r = 0.44; p < 0.05 and r = 0.37; p < 0.05, respectively). There was correlation between HRV reduction and a lower level of physical activity in daily life, besides worse health-related quality of life, functional status, and respiratory and peripheral muscle force. Cardiac autonomic function of patients with COPD is not related to disease severity but mainly to the level of physical activity in daily life.

Relationship between pulmonary function and physical activity in daily life in patients with COPD.

BACKGROUND: It remains unclear how closely the physical inactivity observed in patients with Chronic Obstructive Pulmonary Disease (COPD) relates to the severity of their airflow limitation. Furthermore, it is unknown whether spirometric variables such as maximal voluntary ventilation (MVV) and inspiratory capacity (IC) reflect the level of physical activity in daily life better than the forced expiratory volume in the first second (FEV(1)), the main spirometric variable used to determine the severity of COPD. The objective of the present study was to investigate the relationship between physical activity in daily life and the severity of COPD assessed by different spirometric variables: MVV, IC and FEV(1). METHODS: Forty patients with COPD (21 men; 68+/-7 years; FEV(1) 41+/-14% predicted) were performed spirometry and assessment of the physical activity level in daily life using an accelerometer (SenseWear Armband). RESULTS: MVV was significantly correlated to total energy expenditure per day, energy expenditure per day in activities demanding more than 3 metabolic equivalents (METs), number of steps per day and time spent per day in moderate and vigorous activities (0.42