It causes the outer blood vessels to constrict, forcing more blood into the central circulation where it can be pumped to the muscles, an action which also preserves body heat. Both adrenaline and cortisone cause stored sugars to be released from the muscles and liver to provide energy for the muscles and other organs. Many other physiologic processes are also triggered by these two important hormones in the stress situation, all of which, in the short term, serve to assure the individual's survival to prepare and equip him to swim to shore or stay afloat until rescued. It is when stress becomes chronic, when these physiologic processes designed to aid survival in the short term become switched on continuously, that stress becomes counterproductive. In these situations, patients' illnesses may actually be made worse by chronic stress.
Few illnesses create emotional stress as much as the diagnosis of cancer.
Because the outlook of many cancers can be difficult to predict, patients often feel that they are living under the constant threat of recurrence. This can lead to constant worry, depression, and emotional exhaustion all classic components of chronic stress. Chronic stress leads to excess secretion of adrenaline and cortisone, which can make such coexisting conditions as high blood pressure and diabetes much more difficult to control. Excess secretion of cortisone may reduce the body's capacity to fight off infection, making the individual more susceptible to viral illnesses and other infectious processes. Several studies by Kiecolt-Glaser and others have shown such compromise of the immune system to occur in medical students undergoing the stresses of final exams as well as among the caregivers of patients with Alzheimer's disease.