Here is something I started using many yrs ago that helps knock the edge off those real cold morning/days

I remembered back when I was really young my father use to have one of those handwarmers that you put lighter fluid in and the lite the catalyst and it would burn all day. He used it when snowmobiling in the winter months here in NY. He would place it in his chest pocket of his shirt under his outer clothing.

Well after some searching and a great find at a local garage sale I now have about a half dozen of these little beauties.

I fill them (@ 1 oz of fluid)in the morning before I leave home or camp and place one in my shirt pocket and one in my tubular hand warmer I wear around my waist. They last all day and I have found I stay warmer with this little heat supplier helping to warm my core area.

I did have one concern at first, they do omit a slight I thought, why not place a few drops of cover scent or natural scent on the bags they are kept in. It worked the nuts. I now am warm and have a constant warm scent disperser all in one.

You can locate these hand warmer on the internet, Peacock is one brand as well as Sportsman's

“Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.”
― Albert Einstein