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Tang Yu-hua
HEAT
TOLERANCE
IN
BLACK
AFRICAN
The resistance to
en-
vironmental
temperature
is
similar
in
a
number
of
different
populations thoroughout
the
world.
However,
blacks
have
a
better
resistance
than
do
whites.
The basic
mechanism
by
which blacks
accomodates
to
excessive temperature
is
unknown. Studies
have
estab-
lished that
there
is
an
increase
in the
number
of
functional
melanocytes and sweat glands
in
negroid
skin, This
which
produces more
melanin which
absorbs
ultraviolet
irradiation
from sun
light
and
more
sweat
dissipating
heat
from
the
body
surface. ln addition,
the
unique
curly hair of black
people
preserves
more space
around
the scalp
protecting
against
excessive
sun
light.
All
these
explanations
may help
under-
stand
why the
blacks are
more
use
to
high environmental tem-
perature.
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