In reply to abr1966:
In my twenties, I used to work in a mixed practice. On a Friday I would get the operations done as soon as possible, but there could be a number to get done. I would finish those tasks, then run down the road, across the railway line, to the cattle/sheep market in my rolled up sleeves, left after taking the surgical gown off. Then I would carefully check all the livestock in the various pens, to the frequent comment of "Hey up! Here comes thermal elbows" I was renowned amongst those farmers.
Now I too have several layers more on to keep the insulation level up. Nevertheless, I think that it does me good to go out in the cold, and feel it a bit, to begin with, either on the bike, or out on the peninsula at Rutland water.
Someone above described, what I presume is Reynaud's phenomenon (prev called syndrome): And the best help with that is to keep your core body warm (I suffer from it too). I learned a few years ago at a lecture on the subject, that you can actually further damage your capillaries, not just going out in the freezing temperature, but even between zero and 5 deg C!
Rob