Pros:

vasoconstriction, nerve repair/regeneration and nerve ending regeneration, increase brown fat cells, thermogensis challenge demand to warm up (kcal), mitochondria biogenisis, improved endurance (mitochondria adapt)

improved immunity or fighting off disease/illness, epinephrine/nor-epinephrine stimuli affects hormone system, decrease Alzheimer/dementia

Cons:

hypothermia, death core temp to low (Extreme cases) military training & winter river/lake

Types:

Cold Shower, Ice Bath, Cryo Therapy, Lake, Ocean, River, pool, cold tub (60-65 degrees study)

Recommendations:

start out easy, maybe cold shower for 10-15 sec. You can progress time and temp. progress up to longer showers then move to bathes.

Tips:

cold water is better than nitrogen (Cryo chamber), breathing (hypoxia or whm helps to circulate oxygen to capillaries on skin and numbs nerve endings)