Guessed update.

Physiological preparation
I am guessing that part of the physiological preparation is the gradual build up of brown fat in the body done by gradual exposure to the cold.

It seems the human body does adapt to cold conditions given the right process. Once adapted, then, where as a person not adapted to the cold would normally shiver the person who has adapted wouldn’t.

Exercise increases the thermogenic effect of brown fat.
The use of the brown fat for heat would be on top of the normal process of the bodies normal heat production.

The release of norepinephrine (that is the hormone released under stress) is the hormone that activates an enzyme that splits the brown fat cell causing heat.



Psychological preparation.

Plasticity of consciousness remains a key factor in successful biological adaptation.

Certain Scientists are lead to believe that further evidence is being gained with regards to the normal process of the human bodies heat production, being bye-passed by that persons trained consciousness thought(s).

Combine this with the heat from the brown fat build up on the human body, might be the reasons for the body heat rising while sitting in the cold.

Jude