Assessing individual systemic stress through cortisol analysis of archaeological hair

As a product of physiological status and the social and physical environments, stress has significant impact on health and well-being in both ancient and contemporary societies. In bioarchaeological research, stress is characterized using an array of skeletal indicators that record stressful periods during childhood and adulthood. In modern clinical research, exposure to stress can be assessed using systemic cortisol levels that have been shown to fluctuate in response to experienced stress. Analysis of cortisol levels in archaeological hair should enable assessment of stress during a short, but critical, period of an individual's life. For this pilot study, we selected hair samples from ten individuals from five different archaeological sites in Peru, and analyzed them in segments to determine cortisol levels. These data demonstrate that it is possible to observe biogenic patterns of cortisol production, and that individual experiences of stress can be reconstructed for the period of time represented by each hair sample. Analysis of cortisol levels in hair has the potential to be a valuable short-term dynamic stress indicator that will complement paleopathological and biochemical studies of health and stress, and permit the reconstruction of increasingly detailed life histories.