Abstract
Chronic or long-term stress has numerous adverse effects on health. Many of these effects are mediated through stress actions on the immune system. It is important to elucidate the psychological and biological mechanisms by which chronic stressors adversely affect health, exacerbate disease, or inhibit mental and physical performance because that could enable the development of biobehavioral and pharmacological interventions designed to ameliorate or eliminate the harmful effects of chronic stress. However, it is also important to appreciate that the process of evolution did not select the biological stress response to sicken, handicap, or kill us, but rather to help us survive.