A new study has found that people with early-stage Parkinson's disease who regularly get one to two hours of moderate exercise twice a week, like walking, may have less trouble balancing or doing daily activities later. The study has been published in the 'Neurology Journal'. Researchers found that those who exercised regularly over five years did better on cognitive tests and had slower progression of the disease in several aspects. Parkinson's disease is a brain disorder that leads to shaking, stiffness, and difficulty with walking, balance, and coordination. The study looked at 237 people with early-stage Parkinson's. They had an average age of 63 and were followed by researchers for up to six years. Participants' exercise levels at the start of the study were determined using a questionnaire that measures time and intensity during the previous week of leisure activity, like walking and biking; household activity, like gardening; and occupational activity, like taking care of others. Common cognitive tests were used to measure people's verbal and memory skills and how much time it took to complete mental tasks. It was found it was more important to maintain physical activity over time. Researchers used a common test to rate each person's Parkinson's symptoms on a scale of zero to four, with higher scores indicating more severe impairment. People who got below-average levels of moderate to vigorous exercise, or less than one to two hours, once or twice a week, increased from an average score of 1.4 to 3.7 over six years.