A common suggestion is to warm the blade of your axe underneath your armpit. Obviously, sticking a cold, razor-sharp axe blade inside your coat is not only uncomfortable, but can injure you or cut your clothing.
A simpler and safer way to warm your axe bit is to make a few light chops into the wood before you start chopping at full strength. This warms the blade quickly due to the intense friction of the bit striking the wood fibers.
You can then begin to chop at full power without worrying about damaging your bit.
Jason Schwartz is the founder and senior editor of Rocky Mountain Bushcraft. He is a former Red Cross certified Wilderness & Remote First Aid Instructor, and has taught bushcraft and wilderness survival techniques to the Boy Scouts of America, interned with the US Forest Service, and studied wilderness survival, forestry and wildland firefighting at Colorado Mountain College in Leadville, Colorado. Jason has also written for magazines such as The New Pioneer and Backpacker, including writing the "Tinder Finder" portion of Backpacker's "Complete Guide to Fire," which won a 2015 National Magazine Award (NMA). Email him at rockymountainbushcraft @ hotmail.com (without spaces)