CHICAGO — Aerobic exercise appears to boost mood and daytime alertness in Parkinson’s disease (PD) but falls short of improving most mobility and cognitive symptoms. 

In a small 16-week study of 24 PD patients with mild-to-moderate disease, those who completed moderate- to high-intensity aerobic workouts 5 days a week experienced significant improvement in depression scores and daytime sleepiness. However, the program did not significantly improve overall mobility, balance, fatigue, cognition, or most measures of sleep quality, and key gait tests showed little change.

The study is among the first to evaluate the effects of a structured aerobic exercise program alone on nonmotor symptoms — including daytime sleepiness in PD — study investigator, Joseph Flanigan, BA, research specialist at the University of Virginia movement disorders clinic in Charlottesville, told Medscape Medical News.

Following an aerobic exercise program could also improve quality of life and reduce risk of falls, Flanigan added.

The findings were presented at the American Academy of Neurology (AAN) 2026 Annual Meeting.

Filling a Research Gap 

While aerobic exercise has been shown to improve motor symptoms in PD, its effects on gait, balance, and nonmotor symptoms — including sleep, mood, and cognition — are less well understood, with previous research producing inconsistent findings. 

The impact of“pure” aerobic exercise on nonmotor function hasn’t been extensively explored, said Flanagan. 

To address this research gap, the investigators designed a 16-week purely aerobic exercise program to assess its impact on both motor function and nonmotor symptoms. 

The study included 24 participants with a mean age of 68.1 years who had been diagnosed with PD for a median of 4.4 years. The mean score Movement Disorders Society Unified Parkinson’s Disease rating scale part 3 — which measures motor function — was 28.3, indicating mild-to-moderate disease. 

Patients were not eligible for inclusion in the study if they were already regularly participating in an exercise program. 

Study participants completed 30 minutes of aerobic exercise, 5 days a week, for 16 weeks. All completed moderate-intensity aerobic exercise at home 2 days a week and three supervised, higher-intensity sessions — treadmill walking or jogging, or stationary cycling for those with balance issues — at the University of Virginia kinesiology lab.

Flanigan noted that adherence to the exercise program was high. 

“Patients understood that exercise might help improve their symptoms, so they were motivated to really adhere to the study protocol.”

The primary outcome was the Timed Up and Go (TUG)test where patients stand from a sitting position, walk 3 meters, then walk back and sit down. The test assesses mobility, balance, and fall risk. A time of 14 or more seconds indicates a high risk of falls.

Better Mood, Less Daytime Sleepiness 

Results from the TUG test did not improve significantly (mean change, 0.28; P = .833), a result that Flanigan attributed to a ceiling effect, noting that participants were already performing well on the measure at baseline, leaving little room for improvement. 

Epworth Sleepiness Scale scores (0-24, with higher scores indicating greater daytime sleepiness) decreased by two points at 16 weeks, a statistically significant change (P = .005; 95% CI not specified).

Flanigan said this finding appears to be novel, noting that — to his knowledge — the effect of aerobic exercise on daytime sleepiness has not been previously studied.

Aerobic exercise also appeared to improve mood, with scores on the Beck Depression Inventory — where higher scores indicate more severe depression — decreasing by 1.52 points (P = .004). 

Previous research on the effects of aerobic exercise on depression has been mixed, and a recent review showed no significant benefit for depressive symptoms. However, few of the studies included in that analysis evaluated higher-intensity aerobic exercise. 

“Relative to some other studies, our study was more intense; it was 5 days a week and combined high intensity and moderate intensity exercise. So, it may be that a mixed intensity exercise program might improve depressive symptoms in people with PD.”

Aerobic exercise may improve depression and daytime sleepiness by modulating neurotransmitter systems, Flanigan said. Depression in PD is associated with alterations in dopamine, noradrenaline and serotonin, while excessive daytime sleepiness has been linked to dysfunction in serotonergic, cholinergic, and noradrenergic brainstem pathways, as well as dopaminergic degeneration. 

Looking Ahead 

Researchers also assessed outcomes using the Short Physical Performance Battery, a composite measure of gait speed, balance (including fall risk), and lower-extremity strength. Scores range from 0 to 12, with higher scores indicating better function. Participants showed a 0.75-point improvement (P = .0006).

There was no significant impact of aerobic exercise on cognition, although the study did show a trend for improvements on tests of semantic fluency and executive function.

Study participants may have entered the study“at the top of the range” of cognition, and so “there may not have been enough room for them to improve,” said Flanigan.

In addition, the exercise regime may not have been long enough to have effect on cognition. To improve cognition, exercises may have to involve “more thinking [such as yoga] than just walking on a treadmill,” he added.

There was no significant impact of aerobic exercise on cognition, although the results did show a trend for improvements on tests of semantic fluency and executive function.

Study participants may have entered the study“at the top of the range” of cognition, and so “there may not have been enough room for them to improve,” said Flanigan.

Flanigan said more controlled studies comparing different types and doses of exercise are needed to identify the optimal regimen for motor and nonmotor symptoms of PD. He noted that a key limitation of the study was the absence of a control group.

He added that future studies should consider including nonmotor symptoms as primary endpoints and enrolling patients with specific impairments in those domains. 

A Step Forward for Exercise in PD? 

Commenting on the findings for Medscape Medical News, Abhimanyu Mahajan, MD, associate professor of neurology and rehabilitation medicine at the University of Cincinnati, said the study adds to growing evidence that exercise can improve PD symptoms. 

“The aerobic exercise intervention led to a notable benefit on excessive daytime sleepiness and depression, in addition to physical performance,” said Mahajan.

“While we await additional details in the full manuscript, this report adds to the substantial burden of evidence of the benefits of aerobic exercise on motor and various nonmotor aspects of PD, while empowering patients to be in charge of their own health,” he said. 

Flanigan and Mahajan report no relevant disclosures.