Two chair test: a substitute of 6 min walk test appear cardiopulmonary reserve specific

Abstract

Background: A simple and efficient exercise test possible in a small space is welcome to supplement 6 min walk test (6MWT) that demands a 100 feet corridor to perform.

Methods: The proposed two chair test (2CT) makes a person to sit and move five times between two chairs placed face to face at 5 feet apart and note the changes in pulse-rate (PR) and arterial oxygen saturation (SpO₂) at every 10 s for 2 min after that. Comparison of the post-exercise measurements (PR and SpO₂) with a repeat performance in same patients was done for reproducibility and doing the same after 6MWT and 2CT in another set of patients was meant for for acceptability. The statistical analysis was made on moment to moment change, mean maximal difference and mean cumulative difference for the measurements using p value, z-score, r value and principal component analysis (PCA).

Findings: A total of 40 and 60 volunteers were included for testing reproducibility and acceptability. On both the sets, the difference in most of comparisons between the measured variable (PR and SpO₂) showed the p values remaining insignificant (>0.05), and z-score being <1 SD of the corresponding other and the correlation coefficients (r) remaining excellent (>0.9). Furthermore, the PCA shows complete overlapping. The post-exercise changes did not corelate the walking distance in 6MWT.

Interpretation: The proposed 2CT demands small space and appears reproducible and comparable with 6MWT in terms of its post-exercise impact on PR and SpO₂. This novel test also appears more of cardiopulmonary reserve specific.

Keywords: exercise.

Figure 1

(A and B) Elaborates corelationship between the initial and the repeat tests as regards the changes in PR (A) and SpO₂ (B) with the correlation coefficient (r) being 0.99 and 0.98 respectively signifying excellent reproducibility. (C and D) Similar corelationships (r being 0.97 and 0.91respectively) for post-exercise changes in pulse rate (PR) (C) and arterial oxygen saturation(SpO₂) (D) between 2CT and 6MWT suggest excellent comparability. (2CT, two chair test, PR, pulse-rate; SpO₂, arterial oxygen saturation).

Figure 2

(2A and 2B) Elaborates the co-relationship of the post-exercise mean cumulative chnages in pulse rate and arterial oxygen saturation (SpO₂) with the distance covered in 6MWT (6 minute walk test)

Figure 3

2CT versus 2CT: score scatter plots from the principal component analysis shows no difference of clustering between the initial (red) and repeat (green) two chair test performances by the same patients; the result support that the reproducibility is near perfect. The pulse rate and SpO₂ values collected at every 10 seconds were used for the analysis. (2CT, two chair test.SpO₂, arterial oxygen saturation).

Figure 4

2CT versus 6MWT: score scatter plots in principal component analysis (PCA) show similar and overlapping clustering between the 2CT (red) and 6MWT (green) of the same patients supporting the fact that the two tests are highly comparable. Pulse rate and atrerial oxygen saturation (SpO₂) values from periodic intervals were used for the analysis as described in the protocol.