Effects of resistance exercise intensity on cerebral blood flow and cerebrovascular reactivity in healthy young males: A pilot study.

Exercise intensity has been shown to elicit different cerebral blood flow velocity (CBFv) responses. This study aimed to compare the acute effects of resistance exercise at different intensities on hemodynamics and cerebrovascular reactivity in healthy young males. Eleven healthy young males were recruited, and three trials of dumbbell alternating curls were performed in order of increasing intensity: low (30%-35% 1RM), medium (55%-60% 1RM), and high (75%-80% 1RM). Blood pressure, heart rate, CBFv, and cerebrovascular reactivity were measured at baseline, 1, 5, and 10 min after exercise. (1) At 10 min, the mean blood pressure in the medium-intensity was significantly lower than that at baseline. (2) At 1 min, the systolic velocity of the middle cerebral artery in the medium-intensity increased significantly. (3) At 1 min, the pulsatility index (PI) and resistance index (RI) of the high-intensity increased significantly. At 10 min, the PI and RI of the medium-intensity were significantly lower than the baseline. (4) At 5 min, the breath-holding index significantly increased in the medium-intensity but decreased in the high-intensity. Compared with low and high intensities, medium-intensity resistance exercise may be more effective in lowering blood pressure and enhancing cerebral hemodynamics.