Ok, Tension In The Body Usually Results In Those Parts
Please see detalied answer.
Hi and Welcome to Ask A Doctor service. I have read your question and here is my advice.
Inside temp of our body is constant and necesaary for proper functions of every system of our body. Our body has good power to adjust to some degree of temprature variation and that do not effect our immunity or body systems .Though the body reacts differently to the tempratures to adjust and keep inner body temp constant. However if this coldness or heat both goes to an exteme severity , or for prolong times , either can cause adverse effects on every system of our body including immunity.
Out skin responds to variation in temprature and hence sweats in heat ( to loose heat) and drying and decrease blood flow to the skin to conserve heat in coldness , this may be reasons for why there may be some changes in body parts while exposure to heat or cold .
Regarding immunity , it works good in both hot and cold if to an extent , if severe enough both cold or hot can compromise our body systems .
Yes in specific link to immunity and temperature , we have some sort of immune responses which differ in the two setting like there are some cold antibodies and warm antibiotics that respond in respective temprature. but details of that would be beyond the scope of this discussion.
I hope this help you understand your query, please feel free if you have any specific question or concerns which need to be adressed. I would be glad to answer .
Kind Regards Dr Rahman