It has been shown that when people get into cold water, typically up to their neck, and that cold water, by the way, can range in temperature anywhere from low 40s to low 60s, depending on how long you stay in, that there is a significant increase in the so-called circulating catecholamines. What are the catecholamines? The catecholamines are dopamine, norepinephrine, and epinephrine.