There are several ways that you can self-induce elevations of noradrenaline and adrenaline, and then to learn to anchor your mind and your thinking to stay calm in those elevated adrenaline states as a practice for when stressors hit you in the outside world and your adrenaline and noradrenaline spike. Now, one of the best ways to do this... is to put yourself in a cold shower or other deliberate cold exposure environment.