Do Baseline Glucocorticoids Predict Fitness?

Trends Ecol Evol. 2009 Nov;24(11):634-42. doi: 10.1016/j.tree.2009.04.013. Epub 2009 Aug 11.


Baseline glucocorticoid (cort) levels are increasingly employed as physiological indices of the relative condition or health of individuals and populations. Often, high cort levels are assumed to indicate an individual or population in poor condition and with low relative fitness (the Cort-Fitness Hypothesis). We review empirical support for this assumption, and find that variation in levels of baseline cort is positively, negatively, or non-significantly related to estimates of fitness. These relationships between levels of baseline cort and fitness can vary within populations and can even shift within individuals at different times in their life history. Overall, baseline cort can predict the relative fitness of individuals and populations, but the relationship is not always consistent or present.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Adaptation, Physiological
  • Animals
  • Ecosystem
  • Genetic Fitness / physiology*
  • Glucocorticoids / blood*
  • Stress, Physiological / physiology*


  • Glucocorticoids