Cardiopulmonary Adaptations to High-intensity Interval Training (HIIT) in COPD

"The HIIT intervention consist of 4 intervals with each lasting 4 minutes (4x4min). If a participant reports discomfort related to the length of the intervals or start to feel unmotivated by performing the same exercise, we will use another HIIT protocol: 10x1min.~The 4x4min HIIT consists of a warm-up period of 10 minutes with a target heart rate at 60-70% of HRmax, followed by 4 HIIT intervals with a target HR ≥85%. The intervals are separated by three minutes of active rest, in which the HR should drop to 60% of maximum. Following this, a cool down period of three minutes at warm up intensity is performed.~The 10x1min HIIT consists of a 10-minute warm-up period.The warm-up is followed by 10 intervals, each lasting 1 min at 100% of maximal workload, separated by three minutes of active rest, in which the HR should drop to 60% of maximum. Following the intervals, a cool down period of three minutes at warm up intensity is performed."