The aim is to examine respiratory functions, inspiratory muscle strength, respiratory function, physical fitness and aerobic capacity in Parkinson's disease patients. Individuals between the ages of 50-80 who have been diagnosed with Parkinson's disease by a neurologist and healthy individuals with similar demographic characteristics will be included in the study as a control group. In addition, patients will be divided into three groups as above and below 2.5 and healthy controls according to the Modified Hoehn and Yahr Scale. Demographic information of the individuals will be recorded and clinical evaluations will be made. The staging of Parkinson's patients will be done with the Modified Hoehn and Yahr Scale, and the severity of the disease will be done with the Unified Parkinson's Disease Rating Scale. The inspiratory muscle strength of the individuals will be evaluated with the PowerBreath K5, respiratory functions with the Pulmonary Function Test device, and physical fitness and aerobic capacity with the Senior Fitness Test.