Sedentary behavior was an independent predictor of mortality in subjects with COPD, even adjusting for moderate-to-vigorous physical activity and a number of other variables. Mortality was higher in subjects with COPD who spend ≥8.5 h/d in activities requiring <1.5 MET. These findings may open room for future studies aiming at decreasing sedentary time as a promising strategy to reduce mortality risk in subjects with COPD.

Walking up/downstairs was the most energy-demanding daily activity for patients with COPD. Furthermore, during daily activities, the multisensor showed adequate overall estimation of energy expenditure, as opposed to the pedometer.

The Londrina ADL protocol was a valid and reliable protocol to evaluate ADL performance in subjects with COPD. It is a protocol that can be used in clinical practice and in future studies to investigate ADL outcomes, including those studies that require gas analysis and the wearing of a mask.

The Londrina ADL protocol was reproducible and valid in physically independent adults age ≥50 y. A reference equation for the protocol was established including only age as an independent variable (r = 0.21), allowing a better interpretation of the protocol's results in clinical practice.

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-ofpredicted 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 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.