Figure 1.
Factors that determine skin temperature in the core:shell
concept of thermal balance. The superficial tissues of the body
are regarded as an insulating shell around the inner core in
which heat is produced as a byproduct of metabolism. The large
arrow represents fraction of this heat lost from the body via the
evaporative transfer from the respiratory tract, about 15 - 25%.
The small arrows represent the remainder of the body heat, lost
from the body surface by convective and evaporative transfer to
the environment. Skin temperature, uniform in this model, settles
at an equilibrium level. In cool and neutral environments this
level is the temperature that produces a sufficient gradient
relative to ambient temperature to carry the body heat production
(less respiratory loss) away convectively. In warmer conditions,
evaporation is responsible for an increasing share of the total
heat loss and prevents skin temperature from increasing along
with environmental temperature