Getting regular exercise such as cycling, walking, gardening, cleaning and participating in sports is associated with a lower risk of developing Parkinson's disease in women, according to a study.
The research, published in the journal Neurology, found female participants who exercised the most had a 25 per cent lower rate of Parkinson's disease when compared to those who exercised the least.
The finding only shows an association and does not prove that exercise lowers the risk of developing Parkinson's disease, a brain disorder that causes unintended or uncontrollable movements, such as shaking, stiffness, and difficulty with balance and coordination.
The study included 95,354 female participants, mostly teachers, with an average age of 49 who did not have Parkinson's disease at the start.
Researchers from the University of Pittsburgh, US and Radboud University Medical Center in The Netherlands followed participants for three decades during which 1,074 participants developed Parkinson's disease.
Over the course of the study, participants completed up to six questionnaires about the types and amounts of physical activity they were getting.
They were asked how far they walked and how many flights of stairs they climbed daily, how many hours they spent on household activities as well as how much time they spent doing moderate recreational activities such as gardening and more vigorous activities such as sports.
Researchers assigned each activity a score based on the metabolic equivalent of a task (METs), a way to quantify energy expenditure.
A more intense form of exercise like cycling was six METs, while less intense forms of exercise such as walking and cleaning were three METs.
The average physical activity level for participants was 45 METs-hours per week at the start of the study.
Participants were divided into four equal groups of just over 24,000 people each.
At the start of the study, those in the highest group had an average physical activity score of 71 METs-hours per week. Those in the lowest group had an average score of 27 METs-hours per week.
Among the participants in the highest exercise group, there were 246 cases of Parkinson's disease or 0.55 cases per 1,000 person-years compared to 286 cases or 0.73 per 1,000 person-years among participants in the lowest exercise group.
After adjusting for factors such as place of residence, age of first period and menopausal status, and smoking, researchers found those in the highest exercise group had a 25 per cent lower rate of developing Parkinson's disease than those in the lowest exercise group when physical activity was assessed up to 10 years before diagnosis. Researchers also found that 10 years before diagnosis, physical activity declined at a faster rate in those with Parkinson's disease than in those without, likely due to early symptoms of Parkinson's disease.