Number 207 Arthur D. Little, Inc. CH

 

THE TYRANNY OF TEMPERATURE
J ppEornre his elaborate internal temperature-

control mechanism, optimum temperature
and humidity ranges exist for man, varying
somewhat with activity and the type of clothing
worn. For light work indoors, it appears that tem-
peratures of from 65 to 70° Fahrenheit and rela-
tive humidities of about 60 per cent at the lower
temperature and 40 per cent at the higher give the
greatest feeling of comfort and the best conditions
for efficiency. When sleeping, somewhat lower
temperatures are preferable provided some form
of covering is used to maintain a temperature of
about 80° F, next to the skin. The temperature-
regulating mechanisms of the body are sufficiently
flexible, however, so that in completely dry air
indoors, human beings can tolerate temperatures
—up to 112° when nude and up to 138° when clothed,
} Clothing protects the body not only against cold,

but also against heat, as desert dwellers have long
| known. As the humidity at high temperatures rises

and perspiration evaporates more slowly, clothing
becomes decreasingly valuable. In saturated air
at 88° F., the clothed body is unable to prevent its
internal temperature from rising above normal,
and a genuine fever results. For a nude body, the
| corresponding limit is about 92°F. ,

adigirsts Jo he epi
on

At low temperatures the limit of toleration is
vaguer, since it is greatly affected by clothing and
physical activity ; but when the air inside the cloth-
ing becomes too cool, just as when it becomes too
warm, the body is so fully employed in the task of
: keeping its internal temperature constant that there
is little surplus of energy for any other activity.
‘Much effort has gone into the gathering of ob-
v jective data by which the general level of civiliza-
tion in various areas may be judged, and while it is
easy to overestimate the effect of a given variable,
it does seem that a good climate is an important
aid, although not a guarantee, for a low average
death rate, low infant mortality and high per-
capita income. For example, tests of general cul-
: ture have shown Washington, Oregon, California,
s New York, Connecticut and: Massachusetts high
on the list. Indeed, it has been suggested that de-
velopment of heating means facilitated the spread
of civilization to northern Europe in the Middle
Ages. Similarly, modern air conditioning helps to

& mitigate the situation of the tropics.

 

oS is the department of a

ds -* she substance on which it Lows.