Parkinson’s disease can cause tremors, stiffness and trouble with walking. But a new study suggests that regular exercise can slow the progression of the disease.

Even those with advanced Parkinson’s can benefit from activity, the study authors said.

The research included more than 3,400 patients in North America, the Netherlands and Israel who were followed for more than two years. During that time, Parkinson’s-related changes in mobility were assessed by timing how long it took patients to rise from a chair, walk about 10 feet, turn and return to a sitting position.

The results were published online recently in the Journal of Parkinson’s Disease.

“We found that people with Parkinson’s disease who maintained exercise 150 minutes per week had a smaller decline in quality of life and mobility over two years compared to people who did not exercise or exercised less,” said lead investigator Miriam Rafferty, of Northwestern University and Rehabilitation Institute of Chicago.

“The smaller decline was significant for people who started the study as regular exercisers, as well as for people who started to exercise 150 minutes per week after their first study-related visit,” she said in a journal news release.

The study didn’t look at what specific types of exercise might be best for people with Parkinson’s disease. But the findings suggest that at least 150 minutes a week of any type of exercise offers benefits.

“People with Parkinson’s disease should feel empowered to find the type of exercise they enjoy, even those with more advanced symptoms,” Rafferty added.

The study also found that people with more advanced Parkinson’s disease saw the greatest benefit from 30-minute-per-week increases in exercise. This finding could prove important in making exercise more accessible to these people. Currently, their increased disability may limit their independent participation in community and group exercise programs, according to the researchers.

“The most important part of the study is that it suggests that people who are not currently achieving recommended levels of exercise could start to exercise today to lessen the declines in quality of life and mobility that can occur with this progressive disease,” Rafferty said.