Human biologists have shown increasing interest in the use of cortisol
as an objective marker of stress in recent years. This paper reviews
both practical and theoretical problems raised by this approach. The m
ethodology of cortisol assessment using urine, saliva, and plasma is c
onsidered. There are many practical problems involved in obtaining goo
d measures of cortisol, although the availability of salivary assays o
ffers a promising way forward. Theoretical issues are of greater conce
rn. Results of laboratory studies led to the hypothesis that cortisol
is elevated when an individual is distressed. However, relatively litt
le work has been done on cortisol variation in ''real life,'' and the
results of such studies do not, in general, conform to this hypothesis
. It is concluded that the determinants of cortisol variation are not
well understood. For example, cortisol level may be as much influenced
by positive emotions as by negative emotions usually identified with
stress. Further documentation of cortisol variation in everyday life i
s needed, and at present it is premature to use cortisol level as a ma
rker of stress. (C) 1995 Wiley-Liss, Inc.