>> “It doesn't take any energy to keep a mass at a given temperature.”

>> I wish you would tell my electric bill that :(.

Conductive heat loss in your home is through the surface skin of the house. If you fill up your bathtub with water at the same temperature as the air in your home, it won't take any more energy to maintain your house temp. :)

Cheers,

-Mike

Hi Barry

> Don’t you think it requires more energy to keep that extra mass at 98.6F?
Nope, not when the surrounding internal organs are also at 98.6 C. No thermal gradient from the interior of the bladder: no energy transfer from the interior of the bladder. Basic physics.

> And adding insult to injury, more energy is expended just by the brain telling you to go!
Ah ... I'll pass on that one. Unmeasurable (and extremely small). I wonder though how it compares with the energy expenditure from dreaming, or from snoring?

Cheers

“Conductive heat loss in your home is through the surface skin of the house. If you fill up your bathtub with water at the same temperature as the air in your home, it won't take any more energy to maintain your house temp. :)”

Good example for a physics lesson.

From Roger: “Nope, not when the surrounding internal organs are also at 98.6 C. No thermal gradient from the interior of the bladder: no energy transfer from the interior of the bladder. Basic physics.”

I think that’s the assumption: ‘no thermal gradient’ in a human body. But is our physiology really that simple? It has been suggested we have an internal gradient of 0.1C/cm. And here’s an interesting article “parameters such as density and heat conductivity of the various tissues and variables such as blood flow and metabolic heat production of different organs are spatially distributed and thereby influence the temperature profiles within the human body.” http://jap.physiology.org/cgi/content/abstract/65/3/1110


-Barry