The news for individuals who have a “medium” level of exercise is good: the risk of Parkinson’s disease among those individuals will be lower by as much as 45%, according to a 17-year study.

The study, recently published in Brain: A Journal of Neurology, reportedly tracked 43,368 individuals in Sweden for an average of 12.6 years. The researchers sought to investigate the effect of physical activity on Parkinson’s disease risk, ultimately finding that “a medium amount” of physical activity lower that risk.

Karin Wirdefeldt of the Karolinska Institutet in Stockholm led a research team to evaluate comprehensive information about comprehensive measures of physical activity. Some of the measures included household and commuting activity, occupational activity, leisure time exercise, and total daily physical activity. Data was collected from a group study subjects comprised of 27,863 females and 15,505 males who responded to a questionnaire. For the purpose of this study, physical activity was quantified into metabolic equivalent (MET) hours per day, based on estimated associated with those activities.

All participants were free of Parkinson’s disease on 1 October 1997, the start of the follow-up period. Study participants were followed from this baseline until date of diagnosis with Parkinson’s disease, date of death, date of emigration, or the end of the follow-up period on 31 December 2010, whichever came first. In that time, 286 cases of Parkinson’s disease were identified.

In the study’s multivariable-adjusted model, compared with participants who spent less than 2 hours per week on household and commuting activity, those who spent more than 6 hours per week on the same types of activities had a 43% lower risk of developing Parkinson’s disease. Compared with a low level of total physical activity, a medium level of total physical activity (a mean of 39.1 MET hours per day) was associated with a 45% lower Parkinson’s disease risk in males. Leisure time exercise was not associated with Parkinson’s when analysed alone.