Short-Term High-Intensity Interval Exercise Promotes Motor Cortex Plasticity and Executive Function in Sedentary Females
Question
Does a short-term HIIT program alter motor cortex plasticity and executive-function-related brain activation in sedentary young women?
Summary
Sedentary young women randomized to eight supervised cycling HIIT sessions over two weeks showed changes in motor-cortex excitability and greater prefrontal activation during a Stroop task, but their behavioral Stroop performance did not clearly improve compared with controls.
Methodology
- Healthy sedentary right-handed young women.
- 32 participants.
- Stationary cycling.
- Work intervals: 2 minutes at 90% heart-rate reserve.
- Recovery: 3 minutes at 50% heart-rate reserve.
- Intensity: Alternating 90% and 50% heart-rate reserve.
- About 24-25 minutes including 2-minute warm-up and 2-minute cooldown/relaxation.
- 4 sessions per week.
- 2 weeks.
- Randomized controlled trial
- Intracortical facilitation, Intracortical inhibition, Stroop performance, and Prefrontal activation were tracked.
Outcomes
ICF
Intracortical facilitation decreased in the HIIT group, interpreted by the authors as altered motor cortex plasticity.
Group-by-training interaction p=0.054; HIIT pre-post t=2.76, p=0.015, d=0.690.
SICI
Short-interval intracortical inhibition did not significantly change.
No significant group, training, or interaction effect.
Stroop behavior
Behavioral Stroop task performance did not show a clear HIIT-specific improvement.
Reaction-time training effects were present, but group-by-training interactions were not significant.
Prefrontal activation
HIIT increased activation in left dorsolateral prefrontal and orbitofrontal regions during the Stroop task.
Reported as increased oxygenated hemoglobin activation in left DLPFC and left OFC after HIIT.
Insights
- A short two-week cycling HIIT block can be feasible in sedentary young women under supervision.
- Neural activation changes should not be translated into claims of improved executive performance because behavioral outcomes were not clearly improved.
- Heart-rate reserve targets make this protocol more reproducible than all-out sprint formats.
Limitations
- Small sample.
- Only sedentary young women were studied.
- Menstrual cycle was not monitored.
- Cortical plasticity was measured in a hand muscle while the intervention trained the lower body.
- Short intervention duration and surrogate neurophysiological outcomes.
Safety
- Participants were screened with PAR-Q and TMS contraindication criteria.
- No adverse events were reported in the the paper.