The 1-Minute Sit-to-Stand Test in Adults With Cystic Fibrosis: Correlations With Cardiopulmonary Exercise Test, 6-Minute Walk Test, and Quadriceps Strength

Abstract

BACKGROUND: Exercise testing is part of the regular assessment of patients with cystic fibrosis (CF). We aimed to evaluate (1) the convergent validity of the 1-min sit-to-stand (STS) test in CF by investigating its relationships with peak oxygen uptake (peak V O 2 ), quadriceps strength, and quality of life and (2) to compare these associations with those of the 6-min walk test (6MWT). METHODS: Twenty-five adults with CF (FEV 1 ‫؍‬ 59 ؎ 24%) performed the STS test, the 6MWT, quadriceps strength assessment, and cardiopulmonary exercise test (CPET). Physical activity level, quality of life, and self-esteem were assessed by questionnaires. RESULTS: STS repetitions, 6-min walk distance, quadriceps strength, and peak V O 2 were, respectively, 71 ؎ 12, 90 ؎ 10, 93 ؎ 29, and 62 ؎ 16% of predicted. The STS test had moderate associations with peak V O 2 (r ‫؍‬ 0.56, P ‫؍‬ .004), quadriceps strength (r ‫؍‬ 0.52, P ‫؍‬ .008), and some questionnaire items (eg, perceived physical strength, r ‫؍‬ 0.67, P < .001) only when repetitions were expressed as a product of body weight. Overall, these associations were weaker than those obtained from 6-min walk distance ؋ weight. Oxygen desaturation during the STS test was strongly associated with oxygen desaturation during CPET (r ‫؍‬ 0.80, P < .001). Peak heart rate was lower during the STS test as compared with CPET (P < .001) and the 6MWT (P ‫؍‬ .009). CONCLUSIONS: The STS test cannot be used as a replacement for CPET to accurately assess peak exercise capacity in CF. The STS test may have utility in detecting patients with CF who may exhibit a high level of oxygen desaturation during heavy exercise. Further studies should identify the factors contributing to STS performance to confirm the potential interest of STS repetitions ؋ body weight outcome as a useful submaximal exercise parameter in CF.

The 1-min sit-to-stand test in cystic fibrosis — Insights into cardiorespiratory responses

“…Our data confirm that the 1-min STS test is able to detect oxygen desaturation [15], but to a lesser extent and less precisely than an exhaustive cycle ergometry CPET. Gruet et al [15] showed significant oxygen desaturation (defined as drop in SpO 2 N 4% from rest to peak exercise) during the 1-min STS test in adults with CF. They reported very strong correlations between [20] and Watt max [23].…”

“…The continuous measurement of SpO 2 is recommended during exercise testing in CF [1] and oxygen desaturation (defined as SpO 2 b 90%) during exercise testing predicts pulmonary function decline and the number of hospitalization days over the subsequent 12 months in CF [27]. Our data confirm that the 1-min STS test is able to detect oxygen desaturation [15], but to a lesser extent and less precisely than an exhaustive cycle ergometry CPET. Gruet et al [15] showed significant oxygen desaturation (defined as drop in SpO 2 N 4% from rest to peak exercise) during the 1-min STS test in adults with CF.…”

“…They reported very strong correlations between [20] and Watt max [23]. end-exercise SpO 2 values in the 1-min STS test compared to a cycle ergometry CPET (r = 0.80) [15]. While heart rate at the exercise intensity at which oxygen desaturation occurs can accurately be determined in the conventional CPET (i.e., to provide recommendations on exercise training intensity), the 1-min STS test is rather a screening test for detecting oxygen desaturation.…”

“…This fact, however, should be further evaluated in future studies. Overall the 1-min STS test is less demanding for the cardiorespiratory system [15] and provokes less oxygen desaturation (defined as SpO 2 b 90% at peak exercise) compared to a standard cycle ergometry CPET, thus reducing the extent of hypoxemia and possibly the probability of adverse events. Of note, motion during the STS test complicated the continuous measurement of SpO 2 , which occasionally resulted in poor signal quality, in particular when the measurements were taken at the finger.…”

“…The 1-min sit-to-stand (STS) test has the potential to provide an easy applicable alternative to measure lower limb muscle function and functional exercise capacity [12][13][14][15]. In the last years, the STS test has been increasingly studied in chronic obstructive pulmonary disease (COPD) patients [12,13,16].…”