ADRENALINE, NORADRENALINE, CORTISOL
Cold exposure activates our sympathetic nervous system ("fight and flight"), which prepares us to fight, flight or freeze. Adrenaline is released causing the liver to excrete sugars into the blood veins, to provide the muscles with energy. Noradrenaline, a neurotransmitter, is often released simultaneously, causing us to be awake, and enhance the effectiveness of brown fat. Cortisol, is the long-term 'stress"-hormone, which also ads to the increase of sugar levels in the blood, causing more "energy" to be released, making sure you are alert.
DOPAMINE, SEROTONIN, ENDORPHINS
Dopamine is the "motivation"-hormone, as well a neurotransmitter, and has shown to increase by even 250% practicing cold water swimming at 14 degrees Fahrenheit. The process of the body heating up independently also leads to an increase of dopamine, giving you a dopamine "kick" or "high".
Serotonin is the hormone that decreases during winters, leading to seasonal affective disorder (SAD), often described as the "winter blues". Cold water exposure activates the release of serotonin.
Endorphins are often called the "painkillers", as they are released as a form of Anesthesia. As cold exposure can be not only wildly uncomfortable, but painful, these hormones help to reduce the feeling of pain.
