Parkinson’s and aerobic exercise: 20 trials show better balance and gait

In pooled trial data, aerobic exercise showed the potential to improve balance, walking speed and motor function in people with Parkinson's disease (PD), but a standard quality-of-life questionnaire did not move. That is the conclusion of a systematic review and meta-analysis of 20 randomized controlled trials of aerobic exercise, found by searching PubMed, Web of Science and EBSCO, which first turned up 1,287 records. PD is a progressive neurodegenerative disorder, and the authors cite about 0.3% of the general population and 1–3% of people over 65 as affected.

Why exercise

Medication such as levodopa and surgery such as deep brain stimulation are the usual treatments, but as motor symptoms worsen, drugs work for shorter periods and surgery has safety concerns and side effects. Exercise is a non-drug alternative, and aerobic exercise is the best studied, possibly protecting and restoring neurons by raising neurotrophic factors, reducing oxidative stress and improving mitochondrial function. An earlier review of long-term (12 weeks or more) aerobic exercise included only eight trials; this one widened the evidence to shorter programs.

The trials

Search records were screened for duplicates and relevance; 50 full texts were read, and 30 were dropped (8 combined exercise with other treatments, 19 had no control group, 3 had data that could not be extracted). The 20 trials had 450 participants in 23 exercise groups and 352 in 20 control groups. Most people had mild to moderate PD (Hoehn and Yahr stages I to III; 18 trials, 744 patients), and two trials, 58 patients, covered stages I to IV. Programs included treadmill training, walking, cycling and dance, lasting from 3 weeks to 6 months, and controls got usual care, normal activities or ordinary medication. Eighteen studies were rated high quality; blinding is impossible in exercise trials, which the authors did not count against them.

What changed

Results were consistent across the trials, with low heterogeneity, so no subgroup analysis was run. Only one of the 20 studies reported adverse events (11 in all, 7 in the exercise groups and 4 in controls), and most were not related to the exercise, so the authors judged aerobic exercise safe for people with PD.

Why it may matter, and what is missing

Balance problems are common in PD, and the authors note that falls affect over half of patients, so better Berg and Timed Up and Go scores and faster, longer strides matter for daily life. On quality of life, a few studies found gains at follow-up (two weeks to two months) but not right after the program, suggesting benefits might take longer to show. The PDQ-39 is the most widely used PD-specific quality-of-life scale, but different studies use different scales and few reported it, which limits the conclusion.

Limits the authors name: all the trials were unblinded, quality-of-life data came from only one scale, and only three studies reported follow-up (6 weeks to 6 months), so longer-term effects are unknown. One reported a persistent drop in motor scores at 6 months. The authors say future studies should look at how intensity and duration affect gait and at longer follow-up.

Sources

• A systematic review and meta-analysis on effects of aerobic exercise in people with Parkinson's disease, open-access article on PubMed Central, licensed CC BY 4.0. Changed here: condensed and rewritten, with the flowchart as the only figure; the authors are not named in the copy we hold, so the paper is credited by title and link; rewritten in hubnx's own words.
• Authors of the original: Zhen K, Zhang S, Tao X, Li G, Lv Y, Yu L.