Parkinson's Disease (PD) is a brain disorder that affects movement. This study looks at how a special treadmill called the C-Mill can help people with PD. The C-Mill can be used with or without a kind of video game called virtual reality (VR). The study checks if this exercise helps both the brain and the stomach, also known as the gut-brain axis. The study will have three groups: traditional therapy, C-Mill without VR, and C-Mill with VR.

Doctors will collect samples like stool and blood at three times: before the study, after 21 days, and after 3 months. The study is for people aged 40-70 with moderate to advanced PD who can walk independently.

• Duration: 3 months with multiple check-ins.
• Participation: Requires biological sample collection.
• Risks: Excludes those with certain stomach problems.