The 1-minute sit-to-stand test (1STST) had comparable efficiency as the 6-minute walk test (6WMT) in evaluating functional capacity of post-Covid patients after discharge from the hospital, according to a study presented at the recently concluded European Respiratory Society (ERS) International Congress 2022, which was held in Barcelona.^1,2

This study compared the effectiveness of the 1-minute sit-to-stand test (1STST) vis-à-vis the 6-minute walk test (6WMT) in evaluating functional status of patients in the post-Covid period. Fifty-five patients, mean age ~58 years, from a post-COVID public care clinic in Lisbon were enrolled for the study. The severely ill patients were not included in the study. The participants were instructed to first perform the 1STST followed by the 6WMT after a gap of one hour. During each test, the patients were evaluated for heart rate, oxygen saturation (SpO2) with a pulse oximeter and dyspnea.

A strong correlation was observed for lowest (nadir) SpO2 value between the 6MWT and a 1STST  with correlation coefficient (r) of 0.83. A moderate correlation between the number of sit-to-stand repetitions in the 1-minute test and the distance walked in the 6MWT was also noted (r=0.30). The severity of dyspnea, heart rate and SpO2 between the two tests were comparable and the differences were not statistically significant. The measured heart rate was 102.43 bpm with the 6MWT, while it was 104.72 bpm with the 1-minute test. Dyspnea as assessed by the Modified Borg Scale was 4.79 with the 6MWT versus 5.21 with the 1STST.

Patients who had the lowest functional ability i.e., a score of 3 on the Post-COVID-19 Functional Status Scale also had the lowest SpO2 levels (92% with the 1STST and 93% with the 6MWT), while the nadir SpO2 levels ranged from 95%-96% among those who scored 0-2.

Functional deficit in these patients can red flag the underlying post-Covid pulmonary fibrosis, which has been reported in many survivors of severe Covid-19, enabling timely and appropriate treatment.

Based on their findings, the authors suggest the use of 1STST as an alternative test to assess functional capability of post-Covid patients. It is a simple test and can be performed quickly in a clinic unlike the 6MWT, which is more time-consuming and requires the presence of a doctor/nurse/technician. Even though no special exercise equipment or training is needed for 6MWT, it does require 30 m (100 ft) of flat and hard surface, which may not be available sometimes.

 Reference

1. De Sampaio Nunes Duarte Silva M, et al. Comparison of the 1-minute sit-to-stand test with the 6-minutes walk test for the evaluation of the functional status of post-COVID-19 patients. ERS 2022. https://s3.eu-central-1.amazonaws.com/m-anage.com.storage.ers/abstract_2022/92376.html.pdf.
2. How to Save 5 Minutes in Evaluating Patients Post-COVID. Available at: https://www.medpagetoday.com/meetingcoverage/ers/100548, dated Sept. 6, 2022.