Improved cognitive flexibility after high-intensity interval training (HIIT) in individuals with Parkinson's disease: a pilot randomized controlled trial.
André Hürlimann, Manuela Pastore-Wapp, Tim Vanbellingen
In a 3-week pilot with 10 Parkinson's patients per group, high-intensity interval cycling showed an advantage over steady-state cycling on one cognitive flexibility test but not on four others.
Both groups improved equally on motor and balance scores. Too small to change practice, but it supports a larger trial.
Key findings
1On the Trail Making Test Part B (a measure of cognitive flexibility and set-shifting), the HIIT group improved significantly while the continuous-training group did not, and the between-group difference reached significance. This was the only one of five cognitive tests to show a between-group advantage for HIIT.
2On the Stroop Interference Test (a measure of inhibitory control), the HIIT group improved significantly within itself, but the difference between the two groups did not reach significance, so this cannot be read as HIIT being superior to continuous training on this measure.
3On every secondary outcome — balance (Mini-BESTest), motor function (UPDRS II and III), quality of life (PDQ-39), freezing of gait (FOG-Q), and aerobic capacity (VO2max) — both groups improved or showed no change, with no between-group differences.
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What it does not show
Ten participants per group is very small; the authors themselves call this exploratory and note the limited statistical power increases the risk of missing a real effect. The assessor was not blinded to group allocation, so cognitive scoring could have been influenced by knowing which group the patient was in. Three weeks is a short intervention; the authors acknowledge this may have been insufficient to produce larger cognitive or aerobic adaptations. Several participants could not complete some cognitive tests (TMT-B, Stroop III, Stroop IV), leaving unequal group sizes of 7–10 for those outcomes and introducing missing-data bias. Baseline cognitive ability differed between groups, as shown by a wider range of MoCA scores in the HIIT group, which makes between-group comparisons less clean. The study was conducted at a single site in Switzerland, limiting generalisability.
Declared interests
Funded by the Jacques and Gloria Gossweiler Foundation. The authors state the sponsor had no involvement in the research that could have influenced the outcome.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →