Interval aerobic exercise in individuals with advanced interstitial lung disease: a feasibility study

Background: Aerobic exercise is used in the rehabilitation setting in people with interstitial lung disease (ILD), however little is known about interval exercise as a training strategy. The aim of this study was to compare the cardiorespiratory responses and preferences of a single bout of interval exercise with continuous exercise in individuals with advanced ILD. Methods: Peak work (Wpeak) was obtained from a cardiopulmonary exercise test (CPET). The total volume of prescribed exercise was matched between a bout of interval cycling (alternating 30 seconds at 100% of Wpeak: 30 seconds total rest × 20 min) and continuous cycling (50% of Wpeak × 20 min). Results: Nine lung transplant candidates with ILD were included: 4 men; 62 (6) years; forced vital capacity (FVC) 60% of predicted; and all using supplemental oxygen. Eight (89%) participants reported a preference for interval exercise and one reported no preference (p = .01). One participant required two unintended breaks during continuous exercise. There were no large differences between interval and continuous exercise although some trends emerged. Interval exercise resulted in a lower peak heart rate (124 (12) vs. 132 (15), p = .04) and a trend toward less oxygen desaturation (drop of 8 (4)% vs. 11 (5)%, p = .05) and lower end-exercise Borg leg fatigue (3.8 (2) vs. 4.4 (2), p = .05). End-exercise dyspnea was similar between both exercise modes. Conclusions: Interval exercise was well tolerated and preferred by participants with advanced ILD.