Imagine you've got a strain or a sprain, or you've pulled a muscle and need some do-it-yourself pain relief. Heat packs and cold packs can offer relief, but choosing between the two can be baffling.

With regards to the modalities of heat and cold, each works to modify the blood flow to the muscles and joints in the area applied, says Rahul Shah, M.D., board-certified orthopedic spine surgeon ...

Heat therapy makes your blood vessels dilate, allowing more blood, oxygen and nutrients to be delivered to the inflamed or ...

As temperatures drop, zip up that coat, pull ... heat, Wipfler said. "The main reason you shiver is that the brain detects you are getting cold and sends a signal to the body to increase adrenaline.