Although overexertion and deep freezes do seem to contribute to heart attack risk, the new data suggests that overall
temperature matters less than its variation.
The way plankton absorbed oxygen at a
given temperature mattered less than what proportion of each isotope was available in the sea water as ice sheets came and went.
At
these temperatures matter exists only as a plasma, a soup of negatively charged electrons and positively charged atomic nuclei.
«On the cold edge of a species» distribution,
temperature matters a lot.