Last month I showed you how humans discharge excess heat, when necessary, to keep our core temperature within the 1-degree (centigrade) zone essential for survival. Now that autumn is bringing cooler weather to many of us, let’s see how our bodies ramp up to keep us warm as outside temperatures fall. We can then ask if there are any takeaway lessons for us to consider when we’re designing energy-efficient ways to heat our buildings.
When temperatures decrease too much, most vertebrates, including humans, use two mechanisms to increase heat production. The first way is by involuntary shivering, where muscle contractions convert stored chemical energy into kinetic energy with heat as a byproduct. The second non-shivering way occurs in an unappreciated type of adipose tissue known as brown fat. This is not the same as white fat, which stores most of our body’s excess calories and makes our clothes tight.