High-definition transcranial direct current stimulation enhances exercise-induced hypoalgesia in patients with...

Exercise-induced hypoalgesia is often attenuated in chronic pain. This randomized, double-blind, sham-controlled trial tested whether HD-tDCS over the left primary motor cortex enhances exercise-related hypoalgesic responses, as reflected by pressure pain threshold changes, during aerobic exercise in chronic low back pain. Fifty-two participants received active or sham HD-tDCS while cycling. Pressure pain thresholds and pain-evoked fNIRS responses were assessed before and after intervention. Active HD-tDCS produced larger pressure pain threshold increases than sham stimulation and attenuated pain-evoked activation in somatosensory, motor, and prefrontal regions. Reduced cortical activation correlated with increased pressure pain thresholds, and reduced left dlPFC activation mediated the PPT increase at the tibialis anterior site. These findings suggest that M1 HD-tDCS can augment acute exercise-related pressure pain threshold responses and modulate pain-evoked cortical activity in chronic low back pain.