Ron Clemens

Test-Retest Reliability and Physiological Responses Associated with the Steep Ramp Anaerobic Test in Patients with COPD

The Steep Ramp Anaerobic Test (SRAT) was developed as a clinical test of anaerobic leg muscle function for use in determining anaerobic power and in prescribing high-intensity interval exercise in patients with chronic heart failure and Chronic Obstructive Pulmonary Disease (COPD); however, neither the test-retest reliability nor the physiological qualities of this test have been reported. We therefore, assessed test-retest reliability of the SRAT and the physiological characteristics associated with the test in patients with COPD. 11 COPD patients (mean FEV1 43% predicted) performed a cardiopulmonary exercise test (CPET) on Day 1, and an SRAT and a 30-second Wingate anaerobic test (WAT) on each of Days 2 and 3. The SRAT showed a high degree of test-retest reliability (ICC = 0.99; CV = 3.8%, and bias 4.5 W, error −15.3–24.4 W). Power output on the SRAT was 157 W compared to 66 W on the CPET and 231 W on the WAT. Despite the differences in workload, patients exhibited similar metabolic and ventilatory responses between the three tests. Measures of ventilatory constraint correlated more strongly with the CPET than the WAT; however, physiological variables correlated more strongly with the WAT. The SRAT is a highly reliable test that better reflects physiological performance on a WAT power test despite a similar level of ventilatory constraint compared to CPET.

The Physiologic Effects of an Acute Bout of Supramaximal High-Intensity Interval Training Compared with a Continuous Exercise Bout in Patients with COPD

This study compared physiological responses and work performed during a supramaximal high-intensity interval exercise training session (HIIT) and a constant work rate (CWR) exercise session. Fourteen patients with COPD (mean FEV1   % predicted (±SD)) completed an incremental cardiopulmonary exercise test (CPET) and a steep ramp anaerobic test (SRAT) and then two exercise bouts to symptom limitation on separate days, in random order: (1) a CWR trial at 80% of CPET peak work rate (mean  W) and (2) a HIIT trial using repeats of 30 s at 70% of SRAT peak work rate (mean  W) followed by 90 s at 20% of CPET peak work rate. Subjects ceased exercise primarily due to dyspnea for both HIIT and CWR (64% vs. 57%, resp.). End-exercise , HR, dyspnea, and leg fatigue were similar between the two exercise protocols. Average work rate was lower in HIIT than CWR (32 vs. 63 W, ); however, subjects performed HIIT longer (542 vs. 202 s, ) and for greater total work (23.3 vs. 12.0 kJ, ). The supramaximal HIIT protocol was well tolerated and demonstrated similar maximal physiologic responses to constant work rate exercise, but with greater leg muscle work performed and greater peak exercise intensity.

The diagnostic performance of patient symptoms in screening for COPD

It is recommended that screening for COPD be restricted to symptomatic individuals, but supporting evidence is lacking. We determined the performance of wheeze, cough, phlegm, and dyspnea in discriminating COPD versus non-COPD in a population-based sample of 1332 adults. Area Under the Receiver Operating Curves (AUC) indicated that symptoms had modest performance whether assessed individually (AUCs 0.55–0.62), or in combination (AUC for number of symptoms as the predictor 0.64). AUC improved with the inclusion of multiple other factors (AUC 0.71). Restricting screening to symptomatic individuals is unlikely to substantially improve the yield of general population screening for undiagnosed COPD.