Hazy Shade of Winter

For a few days this week we were bathed in the February sun. As long as you were inside and looking through a window near a heater vent, it was easy to imagine basking in the warmth of the sun. Once you were outside, however, it became a different story.

Clear skies mean lower temperatures. High temperatures have been in the 30s, lows in the 20s, wind chill knocking off about 15 degrees.

Humans are warm-blooded animals, also known as homeotherms. We regulate our body temperature, to the extent we can, balancing heat production from our metabolic sources and heat loss from evaporative cooling (better known as perspiration). In a cold environment, our body heat is conserved by constriction of blood vessels near the body surface and by waves of muscle contractions, or shivering, which serve to increase metabolism. Another heat-conserving mechanism, goose bumps, raises the body hairs; not especially effective in humans, this works well in animals as it increases the thickness of the insulating fur or feather layer.

Cold, of course, is relative. It is much colder in other areas, not so cold in others. What is cold to Cindy isn't that cold to me. Cold is relative to age as well; what wasn't that cold to me in the past is now cold. The natural slowing of metabolism as we age means the body becomes less efficient at generating heat and maintaining our normal body temperature.

Staying warm is a priority. The cats still enjoy sunning themselves in the window, with or without a heater vent. I find socks and a long sleeve shirt are necessary, even with the heater vent.