This stimulates a response to first, reduce circulation to the skin, then to increase circulation by roughly 4x for a period. The period of increased circulation is much greater than the reduced circulation.
I wonder if you wouldn’t get about the same effect just inducing the diver’s response by splashing very cold water on your face?
As boogieman notes, couldn’t the same effect be produced more easily by submerging the subject into ice water for a few seconds?
Maybe there is something to taking a cold shower in the morning to wake yourself up?