*Article* **Is the 1-Minute Sit-to-Stand Test a Good Tool to Evaluate Exertional Oxygen Desaturation in Chronic Obstructive Pulmonary Disease?**

**Ana L. Fernandes \*, Inês Neves, Graciete Luís, Zita Camilo, Bruno Cabrita, Sara Dias, Jorge Ferreira and Paula Simão**

> Pulmonology Department, Pedro Hispano Hospital, 4464-513 Matosinhos, Portugal; inesmaria.neves@ulsm.min-saude.pt (I.N.); graciete.teixeira@ulsm.min-saude.pt (G.L.); zita.camilo@ulsm.min-saude.pt (Z.C.); bruno.cabrita@ulsm.min-saude.pt (B.C.); sara.pimentadias@ulsm.min-saude.pt (S.D.); jorge.ferreira@ulsm.min-saude.pt (J.F.); paula.simao@ulsm.min-saude.pt (P.S.)

**\*** Correspondence: analuisafernandes22@gmail.com; Tel.: +351-916-701-756

**Abstract:** Background: Chronic obstructive pulmonary disease (COPD) is frequently associated with exertional oxygen desaturation, which may be evaluated using the 6-minute walking test (6MWT). However, it is a time-consuming test. The 1-minute sit-to-stand test (1STST) is a simpler test, already used to evaluate the functional status. The aim of this study was to compare the 1STST to the 6MWT in the evaluation of exertional desaturation. Methods: This was a cross-sectional study including 30 stable COPD patients who performed the 6MWT and 1STST on the same day. Six-minute walking distance (6MWD), number of 1STST repetitions (1STSTr), and cardiorespiratory parameters were recorded. Results: A significant correlation was found between the 6MWD and the number of 1STSTr (r = 0.54; *p* = 0.002). The minimum oxygen saturation (SpO2) in both tests showed a good agreement (intraclass correlation coefficient (ICC) 0.81) and correlated strongly (r = 0.84; *p* < 0.001). Regarding oxygen desaturation, the total agreement between the tests was 73.3% with a fair Cohen's kappa (κ = 0.38; *p* = 0.018), and 93.33% of observations were within the limits of agreement for both tests in the Bland–Altman analysis. Conclusion: The 1STST seems to be a capable tool of detecting exercise-induced oxygen desaturation in COPD. Because it is a less time- and resources-consuming test, it may be applied during the outpatient clinic consultation to regularly evaluate the exercise capacity and exertional desaturation in COPD.

**Keywords:** COPD; 6MWT; STST; exercise capacity; oxygen desaturation; prognosis
