I think there is a component here of ability to adapt to changing temps that's missing from this article. Yes, interior heating (and cooling) are problems because instead of having bodies that can handle temp changes, we try to keep our homes a steady temperature. The process of "tempering," a Russian health practice, can improve your body's ability to handle temperature changes.

There is a very common condition called low thryoid disease (most typically Hashimoto's) which affects a large % of women over 40 (some men, too). This leads to low body temperature, especially in the morning. It does not help people sleep and is associated with weight gain due to metabolic derangement. This topic is a complex one that definitely needs more research and discussion.