9518Why 98.6 Degrees? Our Body Temperature Strikes a Perfect Balance
- Jan 3, 2011Why 98.6 Degrees? Our Body Temperature Strikes a Perfect Balance
by Andrew Moseman
December 28th, 2010
Standard human body temperature is 98.6 degrees
Fahrenheit: It's one of those numbers from grade school
science textbooks-like 65 million years since the
dinosaur extinction or nine (eight) planets in the solar
system-that just gets stuck in your head. But why should
it be that balmy temperature and no other?
According to a study by researchers at Albert Einstein
College of Medicine, the 98-degree range is in perfect
Every one degree Celsius rise in body temperature wards
off about 6 percent more fungal species. So tens of
thousands of fungi can infect reptiles and amphibians,
but we can only be invaded by a few hundred fungi. In
the new work, the researchers created a mathematical
model that weighed the fungal protection benefits versus
the metabolic cost of high body temperature. And the
optimal temperature was 98.1, quite close to what
evolution figured out. [Scientific American]
The reason for mammals' hot body temperatures had been
an open question, the scientists say. According to study
coauthor Aviv Bergman and colleagues, while most mammals
keep an inside temperature of about 98 Fahrenheit [37
Celsius], most other animals have considerably lower
body temperatures. As a result, the researchers say,
mammals must spend more time eating to bring in energy.
However, there may be thousands of species of fungus
that can infect amphibians, for instance, but can't
tolerate the hot temperatures inside our bodies.
"This study is a good example of how mammalian evolution
has been driven by both external biological factors and
internal physiological constraints," said Dr. Bergman.
Their study appears in the journal mBio.
[moderator: the study may be found here -