'If you don't mind looking a bit like a Mortal Kombat character, a new electric balaclava would let you keep training like a champ in the cold while lowering the risk of contracting chest infections.' : newatlas.com/stoll-balaclav...
I'm dubious about how heating inhaled cold air could reduce the risk of chest infections, given there needs to be pathogens present to cause infections, but perhaps preventing cold air from damaging cells lining our airways makes it harder for any pathogens to invade our respiratory system? It's rarely below 0/32 degrees where I live, but many many years ago, I did make the mistake one very cold day (barely below zero C) of riding to work and subsequently suffered from painful raw sinuses for a few days. For the record I didn't get a chest infection.
Photo: Frosty fence post