Physical activity tied to slower cognitive decline in Parkinson's

Clinical takeaway: Encourage patients with Parkinson disease to keep up more than four hours of weekly activity in whatever moderate forms they will sustain. Brisk walking, light cycling, doubles tennis, light swimming, and housework such as vacuuming or mowing all counted. 

Clinicians treating Parkinson disease have no drug proven to alter the disease's course, which has heightened interest in exercise as a potential strategy to slow progression. Two randomized trials, Park-in-Shape and SPARX II, found that exercise curbed short-term worsening of motor symptoms. 

Cognitive decline, a major milestone in Parkinson disease progression, has received far less study, and no large trial has tested whether exercise can slow it. Long-term randomized studies are also difficult because maintaining meaningful differences in activity levels over years is impractical and may raise ethical concerns. A longitudinal cohort study has now examined whether weekly physical activity was associated with rates of cognitive decline, alongside motor progression.

Patients reporting up to four hours of activity per week declined an estimated 0.478 points per year on the Montreal Cognitive Assessment (MoCA), a 30-point screen of memory and thinking, which works out to about a point every two years. Those at four to eight hours declined 0.090 points, and those above eight hours 0.007, close to no decline. Both the middle and top groups declined more slowly than the lowest, and the top group did not differ significantly from the middle. Baseline cognitive performance was high, with a mean MoCA score of 26.7.

Associations with motor progression were less consistent. On the MDS-UPDRS-III, a clinician-rated motor exam scored to 132 where higher scores indicate worse function, the low group rose an estimated 0.143 points per year. The middle group fell 0.225 points and the top group fell 0.783. Excluding four rapidly progressing patients in the low group weakened the motor association and left the cognitive one largely unchanged. 

Total physical activity time appeared to drive the associations with both cognitive and motor outcomes. Time spent in vigorous activity was no longer associated with either outcome after adjustment for total activity, although the two measures were so closely related that it was difficult to tell their effects apart. Current activity levels remained associated with both outcomes after accounting for activity over the previous decade, whereas activity during the prior decade showed no independent association.

Researchers analyzed 294 adults with mild to moderate Parkinson disease enrolled in the ongoing Cincinnati Cohort Biomarker Program. Participants reported weekly activity hours in annual interviews, and cognition and motor scores were tracked for a median of three years, up to five for cognition and seven for motor. 

The next test is SPARX3, a randomized phase 3 exercise trial in Parkinson disease expected to finish in 2028. It tests high-intensity treadmill exercise in people diagnosed within three years and not yet on symptomatic treatment. But its primary outcome is change in motor scores over 12 months. Because exercise is assigned rather than reported, it can show whether activity slows motor progression, which a cohort cannot. 

"The possible benefits of physical activity for people with Parkinson's disease may depend on how long they stay active and whether they continue exercising over time," said Dong-Woo Ryu, MD, PhD at the University of Cincinnati and study author. "While our study found small differences between activity levels, these differences may become more meaningful over time. Since participants generally had good thinking and memory skills at the start of the study, our results should be interpreted with caution and further studies are needed." 

Source: Ryu DW, et al. (2026 Oct 7) Neurology. Physical Activity and Motor and Cognitive Progression in Parkinson Disease: A Longitudinal Cohort Study