I think there are lots of good reasons to walk in the morning, especially on cold mornings. But is losing weight one of them?
There is an intuitive logic to the notion that walking — or for that matter, doing much of anything — in the cold will help you lose weight. Calories are, after all, units of heat. If you’re out in the shivering winter weather, it stands to reason that your body will need to burn calories just to keep warm. So you would expect that cold weather would be a plus factor beyond the benefits provided by walking, generally.
Some medical research supports that reasoning — and also indicates that walking in the cold affects the fat cells in the human body. There are unhealthy white fat cells — presumably the jiggly, blobby glop that Brad Pitt and Ed Norton stole from the liposuction clinic to make soap in Fight Club — and healthy brown fat cells, which help the body burn heat. If you’re out in colder temperatures regularly, you apparently increase your supply of that good brown fat. (Incidentally, am I the only person who didn’t know there there was good fat and bad fat?)
Of course, as is always the case in the health area, there are contrary findings. One recent study questioned whether cold-weather exercise burns more calories and also found that low temperatures increase the amount of an appetite-stimulating hormone, ghrelin, in the blood stream. So, when you walk in the cold, you’re not only not burning more calories, you may be setting yourself up for a post-walk, diet-killing chow down of epic proportions.
I’ve long since stopped trying to figure out which of the competing health studies should be followed and simply tried to do what seems to work for me. I like walking in the cold because I like breathing the crisp air, and I feel mentally sharper and more fit when I get to the office. Whether I am actually sharper and more fit, I’ll leave to the researchers.