Intensity Matters: High-intensity Interval Exercise Enhances Motor Cortex Plasticity More Than Moderate Exercise

Area of Science:

• Neuroscience
• Exercise Physiology
• Motor Control

Background:

• Cardiovascular exercise is known to improve brain plasticity.
• The optimal exercise intensity for maximizing neuroplasticity remains unclear.
• Understanding exercise intensity's role is crucial for targeted brain health interventions.

Purpose of the Study:

• To investigate how different exercise intensities affect motor cortex synaptic plasticity.
• To compare the effects of high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) on neuroplasticity.
• To examine the influence of HIIE and MICE on responses to intermittent theta burst stimulation (iTBS).

Main Methods:

• Twenty healthy adults underwent three experimental sessions: HIIE, MICE, or rest.
• Transcranial magnetic stimulation (TMS) was used to measure cortico-motor excitability (CME) and inhibition.
• Measurements were taken before and after exercise/rest, and again after iTBS.

Main Results:

• HIIE significantly enhanced iTBS-induced plasticity compared to rest, increasing CME and intracortical facilitation while reducing inhibition.
• MICE showed an intermediate effect between HIIE and rest.
• The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism was found to attenuate plasticity responses after HIIE.

Conclusions:

• High-intensity interval exercise is more effective than moderate-intensity exercise in enhancing neuroplasticity and iTBS response.
• Exercise interventions aimed at enhancing neuroplasticity should consider high-intensity protocols.
• Genetic factors, like the BDNF Val66Met polymorphism, can influence individual responses to exercise for brain health, suggesting potential for personalized interventions.