We investigated the cerebrovascular and executive function responses to increased inspiratory muscle work. Seven healthy men (33 ± 6 years) performed two separate 10 min bouts of inspiratory pressure threshold loading (ITL) targeting 70% of maximal inspiratory mouth pressure (P Imax) (ITL-Load) and two separate 10 min bouts of ITL targeting 2% of P Imax (ITL-Control). The order in which each participant undertook ITL-Load and ITL-Control conditions was randomized. Transcranial Doppler ultrasonography was used to measure middle cerebral artery blood velocity (MCA V) and executive function was measured using the trail making task (TMT) Parts A and B during the 4-6th min of ITL-Load and ITL-Control. The cerebrovascular conductance index (CVCi) and cerebrovascular resistance index (CVRi) were calculated. There were time x condition interactions ( P <0.01) for MCA V, CVCi and CVRi. This demonstrated during ITL-Load a time-dependent modest increase in MCA V and CVCi, and a time-dependent modest decrease in CVRi. Part A ( P = 0.007) and Part B ( P = 0.013) times for the TMT were slower for ITL-Load compared to ITL-Control. There were no significant correlations between the change in MCA V from rest to the end of ITL and TMT times and errors for Part A ( r = 0.522, P = 0.156) or Part B ( r = 0.370, P = 0.193). This is the first study to demonstrate that ITL results in an increase in MCA V, and a decreased executive function measured by the TMT, but these two measures were not related.