because your body is warm so it heats it up
because you are warm and kitty's like to be warm!!MEOW
the general purpose of a warm up is to let the body know what is coming make sure to stretch a lot and run easy on the warm ups. but it will prevent you from injuring yourself to so always warm up!!
drink hot tea
Homeostasis
Its important to warm up before working out because if you don't warm up there is a higher possibility of pulling a muscle or cramping up because your body will not be physically prepared to work out
Relaxing your body will only make you colder,and shivering is your bodies response when it is cold and is ment to warm your body up a little.There is no way shivering can make your body colder.
The air you breathe out is warm because it has been warmed by your body as it passed through your respiratory system. When you inhale, the air is warmed up to body temperature in your nose and airways, and this warm air is then exhaled back out.
Exercising warms up the body because heat is released as a by-product of the metabolic process that moves the muscles. Your body is oxidizing glucose, protein, or fat in a manner similar to burning fuel, but not as rapid. When you persprire, your body is trying to cool off by evaporation, while at the same time releasing some of the waste products of metabolism.
The initial phase of a warm-up is typically referred to as the "general warm-up." This phase involves performing light cardiovascular activities to increase blood flow and raise body temperature before moving on to specific warm-up exercises.
There could be two reasons, from a common man's stand point. Either A) Your body hits the cold water and it tells itself "Hey! You need to warm up! Or you'll die.", therefore, your body works to warm itself up and you get warm due to the body process. Or B) Heat transfer is at work. This is when two different objects of different temperatures come in contact. The hotter object cools down and the cooler object warms up until both objects are at an Equilbrium or an equal temperature.
Vasoconstriction is the closing of arteries supplying blood to the bodies extremities. As the extremities are the coldest bits of the body, when the arteries constrict less heat is lost from the blood in these areas. This keeps the core of the body warm.