Utility of Breath-holding Test in Systemic Sclerosis

"1. Participants will perform the SHAQ.~2. BHT and 6MWT will be performed in the randomized way for each participant.~3. For BHT, the participants will be told to sit comfortably on a chair, and breath normally. After 1 minute, they were required to make a maximum expiration followed by a maximum inspiration and to hold the breath as long as possible at maximum inspiratory level. This procedure was repeated three times, with 5-minute intervals between the tests.~4. 6MWT will be performed according to the ATS guidelines.~5. Information on CXR, TTE, and PFT (FVC%, DLCO%) will be obtained from the medical record if the data was obtained within 3 months. If not, the tests will be performed.~6. BHT and PFT will be followed by six months after the first breath-holding test to confirm the responsiveness.~7. Additional 30 patients with systemic sclerosis will be collected to perform the test-retest reliability of BHT."