In this study patients will perform one incremental work rate test to obtain peak work rate. On the following days two constant work rate cycle endurance tests (CWRT) will be performed at 60% of Peak work rate using a randomised cross-over design. Between the two CWRTs there will be one hour of recovery time in between.
One of the CWRTs will be performed with the support of non-invasive Ventilation (NIV), the other one without. Respiratory and cardiovascular parameters will be observed through transcutaneous measurement of CO2 (Sentec device) and near-infrared spectroscopy devices.
The purpose of this study is, to examine whether the use of NIV not only decreases patients dyspnoea, but also has positive effects on the patients cardiovascular System, exercise capacity and muscle oxygenation. The investigators will examine the tissue oxygen saturation in the 7th intercostal space (reflecting a respiratory muscle) and on the M. vastus lateralis of the leg during both CWRTs. With the Support of NIV, it is expected to see a change in the oxygenation towards a better perfusion of the leg muscle, due to a facilitation of the work of breathing. This may result in a later onset of leg fatigue and an increased exercise capacity of the patients. To have an equivalent workload all parameters will be compared during isotime.
To conclude, aim of this study is to record the interplay of Oxygenation and Perfusion between the Intercostal muscles and the peripheral leg muscle during exercise. The investigators hypothesize, that the use of NIV may change the oxygenation in favour of the leg muscle through relieving the respiratory muscles.
