Fatigue and Physical Performance During Pulmonary Rehabilitation

Patients with COPD benefit from pulmonary rehabilitation (PR), but a ceiling effect of performance (ie. absence of additional exercise tolerance increase) is observed in 80% of patients from only 20 sessions. An imbalance between intensity, duration and frequency of PR sessions, leading to fatigue development in the course of the PR, could explain this ceiling effect. However, previous studies having evaluated the impact of a PR program on fatigue scores reported either a decrease or no changing, but never an increase. To date, no study has evaluated intermediate variations of fatigue score during a PR program, but were limited to a pre-post PR assessment. Therefore, fatigue fluctuations during PR are unknown. Furthermore, most studies had only unidimensional fatigue assessment. Since fatigue is a multifactorial and a multidimensional process, it cannot be accurately estimated through a unique assessment. Given that most of COPD patients do not increase their exercise tolerance from 20 PR sessions, the investigators hypothesize a significant increase of multidimensional fatigue score between the 1st and the 20th PR session during an inpatient rehabilitation program lasting 4 weeks (40 sessions).

Exercise tolerance is an important predictor of health status in patients with chronic obstructive pulmonary disease (COPD). A reduced 6-min walking distance is associated with an increased mortality risk in these patients. Pulmonary rehabilitation (PR) is one of the most efficient strategy to counterac this effect. Patients improving their exercise tolerance after a PR program have a reduced mortality risk. However, exercise tolerance improvement is not systematic after PR, since up to 1/3 of patients do not respond to the intervention. In addition, PR's effects are limited, with a ceiling effect of performance observed in 80% of patients from 20 sessions. Fatigue could be one candidate to explain the ceiling effect of physical performance during PR. From a theoritical point of view, national and international guidelines on PR have continuously broadened PR interventions for the last 20 years, by progressively introducing in addition to endurance training, resistance training of the lower and then the upper limbs, electrical stimulation, stretching, respiratory muscle training... From a practical point of view, several patients complain of fatigue during PR. However, previous studies having evaluated the impact of a PR program on fatigue scores reported either a decrease or no changing, but never an increase. To date, no study has evaluated intermediate variations of fatigue score during a PR program, but were limited to a pre-post PR assessment. Therefore, fatigue fluctuations during PR are unknown. Furthermore, most studies had only unidimensional fatigue assessment. Since fatigue is a multifactorial and a multidimensional process, it cannot be accurately estimated through a unique assessment. Mutdimensional questionnaires and complementary indicators such as heart rate variability or visuomotor reaction time could be introduced. Given that most of COPD patients do not increase their exercise tolerance from 20 PR sessions, the investigators hypothesize a significant increase of multidimensional fatigue score between the 1st and the 20th PR session during an inpatient rehabilitation program lasting 4 weeks (40 sessions).