I truly and honestly don't care about you at all. You are so insignificant to me.
Brain...
Fine! I'll just have to adapt.
Your body has the tendency to resist change in order to maintain a stable and relatively constant internal environment.
Muscles...
The weather and your surroundings don't function based on you or your feelings. So whether your body is okay with it or not the enviroment is going to be the enviroment.
Enviroment...
If you get either too hot or too cold, sensors in the periphery and the brain tell the temperature regulation center of your brain, in a region called the hypothalamus, that your temperature has strayed from its set point.
Body...
Joke is on you, I can deal with change unlike you. Oh humans are doing this humans are doing that. Oh global warming. Just deal with it.
If your body tempreture is below normal the temperature center in the brain will need to trigger responses that help warm you up. Skeletal muscles contribute to maintaining temperature homeostasis in the body by generating heat. Muscle contraction requires energy and produces heat. Shivering produces random skeletal muscle contractions to generate heat as part of the negative feedback mechanism of maintaining body temperature.