Pulmonary rehabilitation (PR) programs play a key role in reducing the sensation of dyspnea, improving exercise capacity, physical activity level and quality of life in patients with different severity of COPD. However, it is still uncertain whether there is an association between dyspnea and the level of physical activity in these individuals, as patients with different pre-RP baseline dyspnea scores may have different responses in the level of physical activity after PR.

to verify whether there is an association between the sensation of dyspnea and the level of physical activity in response to a PR program in patients with COPD.

This is a retrospective observational study, which evaluated 22 patients diagnosed with COPD, who participated in a PR program for 8 weeks, and had an FEV1/FVC ratio <70%, both genders, mean age of 67 ±SD years, post-bronchodilator FEV1 (48±12%). For pre- and post-PR evaluation of dyspnea sensation, the mMRC scale (Medical Research Council), distance covered by the 6-minute walk test (DPTC6) and the level of physical activity through the activPAL3TM actigraph (Pal technologies Ltd. United Kingdom), for 7 consecutive days. The physical activity level variables analyzed were time in lying/sitting, standing, and walking positions; number of steps, and time spent at certain exercise intensities (sedentary, when METS<1.5 and light exercise, when MET <1.5 but <3). Those patients who could not perform the proposed tests and/or had difficulty understanding the scale were excluded. For correlation analysis and linear regression of the data, the statistical software SPSS v21(2012) was used, with significance of p<0.05.

A high negative correlation was found between mMRCpre and DPTC6 (r=-0.769; p=0.000), as well as a moderate negative correlation with the number of steps (r= -0.678; p =0.001), walking time (r= - 663 ; p= 0.001) and METS(> 1.5 to 3.0). Regarding mMRC and sitting/lying time, there was a moderate positive correlation (r=0.546; p= 0.009). It was found in the simple linear regression analysis between mMRC with 6MWT (r² =0.529), with the number of steps (r² =0.451), with walking time (r²=0.463) and with MET > 1.5 to 3.0 (r²= 0.519).

it is concluded that the pre-intervention mMRC can explain the exercise capacity and the level of physical activity after PR, and more symptomatic patients reached lower exercise capacity and less time in light and moderate physical activity intensities.

This study has the clinical implications that when prescribing a PR program for patients with more symptomatic COPD, greater attention is given to these patients so that there is an improvement in exercise capacity and physical activity level.