Exercise intensity affects acute neurotrophic and neurophysiologic responses post-stroke

Aerobic exercise may acutely prime the brain to be more responsive to rehabilitation, thus facilitating neurologic recovery from conditions like stroke. This aerobic priming effect could occur through multiple mechanisms, including upregulation of circulating brain-derived neurotrophic factor (BDNF), increased corticomotor excitability and decreased intracortical inhibition. However, optimal exercise parameters for targeting these mechanisms are poorly understood. This study tested the effects of exercise intensity on acute BDNF and neurophysiologic responses. Sixteen ambulatory persons >6 months post-stroke performed three different 20-minute exercise protocols in random order, approximately one week apart, including: A) treadmill high-intensity interval training (HIT-treadmill); B) seated-stepper HIT (HIT-stepper); and C) treadmill moderate-intensity continuous exercise (MCT-treadmill). Serum BDNF and transcranial magnetic stimulation measures of paretic lower limb excitability and inhibition were asses...