As ageing is associated with immunological changes, the effects of stress and age are interlinked where a deregulation of the immune function can have a significant impact on physical health. On the other hand stess can both enhance and increase the effects of aging, with older adults often showing greater immunological impairment to stress than younger adults. Therefore a good immune response is essential to our good health. In the same way immunological alterations and disturbances can influence the progression and severity of a variety of disorders and diseases, including stress related disorders.

Also stressful experiences very early in life can alter the responsiveness of the nervous system and immune system. It is possible that prenatal or early life stress may increase the likelihood of altered immune responses to stress in late life. One such alteration to the immune system includes a decrease in the ability of white blood cells (immune cells) to carry out their key functions. One great example is temporary stress as seen in students during “examination stress". This has been seen to slow down wound healing. Children of mothers who are routinely stressed during their pregnancy show decrease in immune function compared to children of undisturbed pregnancies. Similarly young children who experience abuse or neglect show abnormal cortisol levels indicative of a dysregulated stress response. Cortisol is a hormone secreted by the adrenal glands and involved in glucose metabolism, blood pressure regulation, maintenance of insulin release, suppression of inflammatory responses. Cortisol is elevated following several stress disorders. Several stressful experiences can cause in areas of the brain involved in memory an “imprinting" during fetal development and early life can alter the responsiveness of the endocrine, immune, and central nervous systems for many years. An understanding of such interlinked effects of stress and age is important to understand and to determine the mechanisms involved, so that we can develop effective interventions in early and late life.