Getting “the shivers” when you’re cold is a way for your body to increase heat generation via muscle contraction, and is usually involuntary. You can help the process along by voluntary movements as well. Next time you’re feeling cold: grip and relax your hands, curl and relax your toes, do squats, and maybe even do some push-ups! Movement helps get you warmer, quicker. A quick mini-workout is a good tool.