the.com/shiver
your body's involuntary attempt to start a fire by shaking very, very hard
how it worksMuscles spasm rapidly to generate body heat
the goosebumpsTiny muscles raise hairs to trap warm air
fever twistYou shiver when feverish to raise temperature higher
not just coldFear and emotion trigger the same reflex
old wordRooted in a term meaning to splinter or fragment