Introduction/Aim: Exertional dyspnea (ED) remains the primary diagnostic symptom for chronic lung and heart disease populations. Whilst a number of exercise tests have been described, there remains no gold standard clinical measure of ED. The purpose of this review was to examine the type, reliability and responsiveness of fixed-intensity exercise tests that assess ED in chronic respiratory and cardiac populations.

Method: A systematic search of electronic databases (PubMed, Cochrane, CINHAL, Medline, Embase, Scopus) performed between February and July 2021 identified papers that examined: (a) fixed-intensity exercise tests and measured ED, (b) chronic respiratory and cardiac populations, (c) exertional dyspnea reported at isotime or at completion of fixed duration exercise test, (d) published in English.

Results: Searches identified 6037 papers. One hundred thirteen papers were included, covering exercise tests using a variety of fixed-intensity protocols and modes. Four categories were identified: (i) cycle (n = 84), (ii) walking [including treadmill (n = 18), endurance shuttle walk (n = 3), overground (n = 1), 3-min shuttle (n = 4)], (iii) step test (n = 7), (iv) arm exercise (n = 4). Most studies (96%, 108/113) were performed in chronic respiratory disease. Nearly all studies (93%, 105/113) used a supervised incremental exercise tests to exhaustion to set the intensity of exercise. Thirty percent of studies (34/113) used a fixed duration for the exercise test, the remaining 70% (79/113) using an exhaustion protocol recording exertional dyspnea at isotime. ED was measured using the BORG scale in 90% (102/113) of studies. Seven percent (8/113) of studies reported test–retest reliability, with ICCs ranging from 0.583 to 0.91. Most studies (73%, 82/113) examined the change in ED in response to different interventions including short- and long-acting bronchodilators.

Conclusion: Considerable methodological variety of fixed intensity exercise tests exists to assess ED, most test protocols require supervised incremental exercise tests to set target intensities. There does not appear to be a simple, universal test for measuring exertional dyspnea in the clinical setting.