Hot and Cold Immersion?

I do exercise but id just like to discuss and get your feedback on hot and cold immersion, cause i believe there is more to it then people think :S so I'm going to discuss my experience and leave some links.

When we work out at anytime we work out the body's temperature is higher then its core temperature which in my opinion results in cardio health and heart health cardio Etc., have you ever been relaxed in a hot bath or sauna to only realise your heart is working as if you was taking a run? well the body is in the process of working out even though your relaxed and this is burning calories and weight, why do some people run with more layers on and wrap in Clingfilm to burn more weight? because it increases the body's temperature even more resulting in more weight loss, what about cold immersion? people who adapt to cold climates or immerse there body's in ice or even freezing cold showers the body then activates its brown fat and metabolism and uses all its energy to get the body back to its core temperature giving the metabolism a dramatic boost again weight loss, so I'm starting to believe even though exercise can build muscle and give someone extreme confidence and a good image is it actually the cause of burning weight and being in optimal health? in my opinion I don't believe so I've tried passive heating, extreme cold immersion and hydrotherapy a mix of both and I haven't felt better, I'm gonna leave some links below and any feedback or advice good or bad :)