**7. Noninvasive mechanical ventilation (NIMV)**

Exercise tolerance is increased by noninvasive mechanical ventilation (NIMV), because the acute stress on the respiratory muscles is lessened. These mechanisms explain why the impact of NIMV on PR results has been studied in various studies where NIMV was used at night or during exercise training [30]. The effect of NIMV during exercise training as part of PR was examined in a review of the Cochrane Database, and it was found that doing so increased lower limb exercise capacity and permitted exercise at higher training intensities [31, 32]. No studies looked into the impact of NIMV during exercise training on physical activity, and there was no conclusive evidence regarding quality of life. It has also been demonstrated that nocturnal NIMV following PR increased exercise tolerance and quality of life in patients with severe COPD, presumably by giving the respiratory muscles a rest at night. The ERS/ATS guidelines state that NIMV may be used as an additional therapy to unload the respiratory muscles so that certain patients with severe chronic respiratory disease who do not respond well to exercise can intensify their exercise regimen [14, 30].

*Current and Contemporary Developments in Pulmonary Rehabilitation DOI: http://dx.doi.org/10.5772/intechopen.107050*
