title: Energetics of thermoregulation by an industrious endotherm.
abstract: OBJECTIVE
  Thermoregulation by modern industrial humans is unique among endothermic animals, in that it is largely accomplished by controlling the temperature of our external environment. The objective of this study was to view the relationship between thermoregulatory energy use and environmental temperature in modern humans from the perspective of comparative physiology.
  
  
  METHODS
  Monthly residential energy use estimates from the US Energy Information Administration were divided by the annual number of American households from the US Census Bureau, giving average monthly energy consumption per American household for the years 2006 through 2010. Monthly energy consumption was then plotted against average monthly temperature across the United States from the National Climatic Data Center.
  
  
  RESULTS
  The resulting graph bore a striking resemblance to a classic Scholander-Irving curve, exhibiting clear upper (22°C) and lower (15°C) critical temperatures, and an increase in energy use as temperatures extend above (90 W °C(-1) increase) or below (244 W °C(-1) decrease) those critical temperatures. Allometric equations from comparative physiology indicate that the energetic costs of our current thermoregulatory habits are ∼30 to 50 times those predicted for an endotherm of our size.
  
  
  CONCLUSIONS
  Modern humans have redefined what it means to be a homeothermic endotherm, using large quantities of extrametabolic energy to regulate the temperature of our surroundings. Despite this sophistication, the signal of our individual physiology is readily discernible in national data on energy consumption.
authors.affiliation: Department of Entomology, University of Wisconsin-Madison, 53706, USA. tmeehan@wisc.edu
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Meehan
mesh_terms: D001833:Body Temperature Regulation; D004734:Energy Metabolism; D004736:Energy-Generating Resources; D006801:Humans; D013696:Temperature; D014481:United States