Self-regulation of temperature

Heat.. How to become colder when it is warm..

Find any organization with air conditioner like library store etc.

Find a canopy or shadow.

Water is the great source to become cooler. Merely swimming and sitting in the water helps a lot. If we have only bottled water, it is useful to soak clothes with that. Then put on wet clothes, they will serve as a coolant longer than if we just spray this water on a naked body. Clothes dry longer, especially those made of particular kinds of fabric like jeans e. g.

Underground and basement. Soil provides great insulation against high temperature. 

Cold.. How to get warmer when it is cold outside..

Find any organization where interior temperature is high enough - library, store etc.

Put on all the clothes we have.

Stretch. I don't know how it works, but stretching helps to make body temperature higher. Simple stretching for 5 minutes works fine: kiss your knees etc.

Push-ups and squats. Don't take care about people opinion around. Body temperature is more important.

Running. Good to combine with some useful goal - like running to the store etc.

Snow. In the extreme conditions like if we are alone in the wild forest we need to use extreme means to become warmer. While snow per se is cold, it provides a great temperature insulation. Northern people make igloo of snow and ice. Igloo is very warm inside. We can try to make something like that faster, by merely digging a hole (a cave) in the existing snow pile. Meanwhile, digging is also physical exercise, it per se makes us warmer in the process of doing it.