Parkinson’s disease, in most patients, is possibly caused by natural oxidative stress in dopaminergic neurons, insufficient exercise and galactose induced oxidative stress. Dopamine oxidizes to produce oxygen radicals that damage neurons. Exercise generates lactic acid and myokines that are essential for brain health. Galactose produces oxidative stress in the brain. These factors change with age and lifestyle. It is likely that lifestyle interventions, including daily exercise and much less alcohol and milk consumption, can delay or prevent Parkinson’s disease.