Effect of physical effort on postural balance in COPD and OSA

Background: Chronic obstructive pulmonary disease (COPD) individuals have worse postural balance and a higher prevalence of obstructive sleep apnea (OSA). However, the effect of physical exertion on the postural balance in individuals with COPD and OSA remains unknown. Aim: To evaluate the impact of physical effort on the postural balance in individuals with COPD and OSA. Methods: Moderate to very severe COPD individuals were evaluated on two visits. On day 1, they underwent a polysomnography exam and were classified into without (wOSA) or with mild (mOSA) or moderate to severe OSA (msOSA). Postural balance was evaluated through a force platform and the center of pressure (CoP) was assessed in two support positions: ‘open base’ and 9semi tandem. The CoP was assessed at rest and after physical exertion (4 to 7 on the modified Borg scale). Between-group difference was evaluated using ANOVA two-way followed by post-hoc Tukey test. Results: Sixty-seven individuals were evaluated (wOAS, n=27; mOAS, n= 24; msOAS, n=16). No between-group differences in age, sex, and FEV1 were observed. Before physical exertion, all groups presented similar postural balance (p>0.05). However, after physical exertion, an increase in total CoP displacement was observed in the wOAS and mOAS (p<0.05) in the ‘open base’ position compared with pre- effort. mOAS also increased CoP displacement in the ‘semi tandem’ position after physical exertion (p<0.05). Conclusion: Our results suggest that physical effort worse postural balance in COPD individuals with or without mild OSA. Individuals with moderate to very severe COPD present worse postural balance that is not modified with physical effort.