Andréa Daiane Fontana

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<or=r<or=0.52; p<0.01 for all). Correlation of these variables with IC and especially FEV(1) was more modest, borderline or not statistically significant. There was no difference in time spent in vigorous activities among patients classified according to the FEV(1)-based GOLD stages II, III and IV, differently than that observed when patients were classified in groups according to their MVV. CONCLUSION In COPD patients, MVV better reflects the physical activity level in daily life than FEV(1) and IC.

Comparison of daily physical activity between COPD patients from Central Europe and South America

BACKGROUND In healthy elderly and adults, lower physical activity level in daily life has been associated with lower socio-economic level and non-Caucasian race. The objective of this study was to determine if this is also applicable in chronic obstructive pulmonary disease (COPD) by comparing physical activity levels in daily life in stable patients from two countries (Austria and Brazil) with different socio-economic and ethnic characteristics. METHODS Physical activity in daily life was objectively assessed in 40 Austrian and 40 Brazilian COPD patients. Groups were matched for age, gender, body mass index, disease severity, smoking history, presence of concomitant heart disease, lung function, dyspnea and functional exercise capacity. In addition, climatic conditions were similar during the period of data collection in the two groups. RESULTS In comparison to Brazilian patients, Austrian patients had a significantly lower walking time (p=0.04), higher sitting time (p=0.02) and lower movement intensity (p=0.0001). The proportion of patients who did not reach an average of 30min of walking per day was 48% in the Austrian group and 23% in the Brazilian group. CONCLUSIONS Austrian patients with COPD showed a significantly lower daily physical activity level in comparison to matched Brazilian patients. Socio-economic and ethnic factors appear to influence stable COPD patients differently than described in previous studies including healthy subjects.

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<r<.68). The agreement between methods was also good, according to Bland-Altman plots. The device was reproducible for registering SC, WD, and EE during slow walking and for all variables during fast walking (intraclass correlation coefficient >.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 devices 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.